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Name the types of photoreceptors.
Name the different parts of the brain.
The brain can be divided into three major parts:
(i) forebrain,
(ii) midbrain, and
(iii) hindbrain
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The deep cleft in the brain divides the cerebrum longitudinally into two halves, which are termed as
the left and right cerebral hemispheres
Ganglion is the collection of nerve cells. It is a structure containing a number of nerve cell bodies, typically linked by synapses, and often forming a swelling on a nerve fibre.
The labyrinth is the fluid-filled inner ear. It consists of two parts, the bony and the membranous labyrinths.
The bony labyrinth is a series of channels, inside which lies the membranous labyrinth, which is
surrounded by a fluid called perilymph.
The membranous labyrinth is filled with a fluid called endolymph. The coiled portion of the labyrinth is called cochlea.
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The meninges are the protective covering of the brain. Meninges consist of three layers called
dura mater, a very thin middle layer called arachnoid and an inner layer called pia mater.
The process of splitting of rhodopsin into its components in the presence of light is called bleaching of rhodopsin.
Between the electrical and the chemical synapse , which has a faster transmission?
The saltatory conduction helps in:
1. It increases the velocity of nerve impulse transmission.
2. It uses less energy.
Corpus callosum joins the two cerebral hemispheres. It helps to connect the right and the left cerebral hemisphere.
The arrival of the stimulus at a site of the nerve membrane makes it freely permeable to Na+ ions at that point. There is a rapid influx of the sodium ions, followed by the reversal of the polarity of the membrane, that is inside of the membrane becomes positive and the outer surface becomes negatively charged. This is called depolarisation.
Myeling sheath provides electrical insulation and increases the speed of the nerve transmission.
1. Grey matter is made up of nerve cell bodies, and white matter is made up of fibers.
2. Unlike the white matter, the neurons of grey matter do not have extended axons.
3. Grey matter occupies 40 percent of the brain, while white matter fills 60 percent of the brain.
4. Grey matter has a grey color because of the grey nuclei that comprises the cells. Myelin is responsible for the white appearance of the white matter.
5. Processing is concluded in the grey matter, while white matter allows communication to and from grey matter areas, and between the grey matter and the other parts of the body.
6. Grey matter has no myelin sheath, while white matter is myelinated.
Functions :
The medulla contains the control the foloowing things
(a)It controls the rate and depth of breathing.
(b) It controls the rate of heart beat.
(c) It controls the flow of gastric juices.
(d) It controls the act of swallowing.
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The general functions of the nervous system are:
1. It receives the stimulus, transmits it to the other parts of the body.
2. It controls and regulates various activites of the organs and the organism as a whole e.g. muscular contraction, sense of vision, hearing, pain etc.
3. It detects changes and signals the brain.
The nervous system is divided into two main parts:
1. Central Nervous System (CNS) : The CNS consists of the brain and the spinal cord and is the site of information processing and control.
2. Peripheral Nervous System (PNS) : It is formed the nerves. The nerves which arise from the central nervous system constitute the peripheral nervous system.
The PNS can be further divided into two parts that is :
i. Somatic neural system.
ii. Autonomic neural system.
The entire process of response to a peripheral nervous stimulation, that occurs involuntarily effort or thought requiring the involvment of a part of the central nervous system is called a reflex action.
The reflex pathway comprises of:
i. One afferent neuron (receptor) at least one.
ii. One efferent (effector or excitor) neuron appropriately arranged in a series
The afferent neuron receives signal from a sensory organ and transmits the impulse through the dorsal nerve root into the CNS at the level of spinal cord. The efferent nueuron carries signals from CNS to the effector. The stimulus and response thus forms a reflex arc .
The reflex action follows a definite path which is in the form of an arc and this path is called reflex path.
The mechansim of reflex action can be described in following steps :
1. Reception of stimulus : The receptor organs (sensory organs) receive the stimulus and they transfer it to afferent nerve fibres.
2. Conduction of stimulus : The afferent nerve fibres conduct the stimulus to grey matter of spinal cord.
3. Conversion of stimulus into order : In grey matter of spinal cord, stimulus is converted into order by neurons.
4. Conduction of order : The order is carried by efferent nerve fibres to effectors (muscles).
5. Action of muscles : The muscles or effectors after receiving the order act accordingly.
Action potential : It is a very rapid change in axon membrane potential from the negative resting potential to a positive peak and then back to resting potential. It is the electrical potential difference across the plasma membrane at the site of the stimulus is called active potential.
The afferent fibres transmit impulses from tissue/organs to the Central nervous system
While the efferent fibres from the CNS to the perpheral tisues or organs.
Differentiate between
(e) Cerebrum and Cerebellum
Cerebrum |
Cerebellum |
Largest part of the brain |
Smaller than Cerebrum |
It controls voluntary movements, and is a seat of will. |
It maintains posture and equilibrium. |
It is a part of the forebrain. |
It is a part of the hind brain. |
Main properties of nervous tissue :
1. Excitability : In response to stimulus the nerve cells and fibres enter into active state, then this state is called state of excitation. Excitation arises as receptors on account of various stimulus which may be mechanical, chemical, electrical or thermal.
2. Conductivity : It is the transmission of excitation. Excitation is transmitted along the nerve fibres.
Definition : Receptor is a sensory organ which receives stimuli from environment or from inside the animal and passes impulses to the nervous system. These are usually present on the post-synaptic membrane .
Afferent neurons |
Efferent neurons |
Afferent neuron conducts nerve impulses toward the brain or the spinal cord.
|
Efferent neuron conducts nerve impulses from the brain or spinal cord to the effector organs such as muscles or glands. |
It carries signal from a sensory organ and transmits the |
It carries signals from CNS to the effector |
Myelinated axons |
Non myelinated axons |
1. It has myelin sheath. 2. Nodes of Ranvier present. 3. These are present in white matter and peripheral nervous system. 4. Conduction of nerve impulse is saltatory. |
1. Absent. 2. Absent. 3. Their are present in sympathetic and para sympathetic nervous system. 4. It is smooth. |
Dendrites |
Axon |
1. These are smaller is size. 2. One or many dendrites arise from a cyton. 3. Dendrites have nissl’s granules. 4. Synaptic knobs absent. 5. They do not release acetylcholine 6. They receive the nerve impulse from previous neuron. |
1. These are larger in size.
5. They release acetyl choline. 6. They transfer the nerve impulse to dendrites of next neutron. |
Rods |
Cones |
1. They are more in number about 125 million in human eyes. 2. Outer segment is cylindrical. 3. Has protein rhodospsin. 4. They are sensitive to dim light. 5. Do not perceive colour. 6. They are of one type.
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1. They are comparatively very less in number about 6 million in a human eye. 2. Outer segment is conical. 3. Has protein iodopsin. 4. It is sensitive to bright light. 5. Perceive colour. 6. They are of three types. |
Thalamus |
Hypothalamus |
Thalamus is the part of the forebrain that receives nerve impulses of pain, temperature, touch, etc., and conducts them to the cerebral hemisphere. |
Hypothalamus is the part of the forebrain that controls involuntary functions such as hunger, thirst, sweating, sleep, fatigue, sexual desire, temperature regulation, etc. |
Chambers of eye : The eye is divide into two chamber by the lens and suspensory ligament.
These chambers are :
1 .Anterior chamber : It is also called aqueous chamber. It lies between lens and cornea. It is filled with aqueous humour (lymph like fluid) which provides nutrition to cornea and lens. It is secreted by the ciliary body.
2. Posterior chamber : It lies between lens and optic part of retina. It is filled with vitreous humour which keeps the eye distended. It also provides nutrition to the eye.
Accommodation of eye : Itis the adjeustment of the eye to see near and far object.
When the object is near, ciliary muscles in the eye contract and suspensory liagament becomes loose. As a result, lens becomes more convex and focal length of lens decreases.
If the object is away the ciliary muscles expand.
The focal length of lens increases and convexity decreases.
This process of adjustment of eye to the near and far objects is called accommodation of eye.
The mechanism of vision:
i. The light rays in visible wavelength is focussed on the retina through the cornea and lens generate potentials (impulses) in rods and cones.
ii. The photopigments which is composed of opsin and retinal is dissociated into opsin and retinal because of light. .
iii. The change in the structure of the opsin causes changes in the membrane permeability.
iv. A potential differences is generated in the photoreceptor cells which produces signal that generating action potentials in the ganglion cells through the bipolar cells.
v. The action potential is transmitted by the optic nerves to the visual cortex area of the brain, where the neural impulses are analysed and the image is formed on the retina is recognised.
Photorecepors : The receptor cells of eye which are light sensitive and have the photo-pigments are called photoreceptors or visual cells.
They are of two types 1. rod cells 2. cone cells.
1. Rod cells : The rod cells contain a purplish pigment called rhodopsin. They funcion in dim light and at night. They are responsible for the Scotopic vision.
Bleaching : Bright light splits rhodopsin into a scotopsin and a carotenoid pigment retinene or retinal and this process is called bleaching.
Dark adaptation : In the dark, rhodopsin is resynthesized from scotopsin and retinal. This process is called “dark adaptation.” It makes the rods functional.
2. Cone cells : The cones have a pigment called iodopsin. They function in daylight and artificial bright light produces images and give colour vision.
The cone cells conain three different wavelength.One pigment (erythrolabe) is sensitive o red light another (chlorolabe) to green and the third (cyanolabe) to blue.
The eye balls are moved by six extrinsic muscles, attached at one end to the eyeball and other to the wall of the orbital cavity.
They are :
(1) Medial rectus - The medial rectus rotates the eyeball inwards.
(2) Lateral rectus - The lateral rectus rotates the eyeball outwards.
(3) Superior rectus - The superior rectus rotates the eyeball upwards.
(4) Inferior rectus - The inferor rectus rotates the eyeball downwards.
(5) Superior oblique - The superior oblique rotates the eyeball so that the cornea turns in downward and outward direction.
(6) Inferior oblique - The inferior oblique rotates the eyeballs so that cornea turns upwards and outwards.
Explain the following processes:
(a) Polarisation of the membrane of a nerve fibre.
During resting condition, the concentration of K+ ions remains more inside the axoplasm while the concentration of Na+ ions remains more outside the axoplasm. As a result, the potassium ions moves from inside to outside because of the concentration gradient inside and outside the membrane. The K+ ions move faster as compared to sodium ions. Therefore, the membrane becomes positively charged outside and negatively charged inside. This is known as polarization of membrane or polarized nerve.
During an electrical stimulus the action potential is generated. The membrane becomes permeable to sodium ions than to potassium ions. Thus an outer side membrane has –ve charge and on inner side it gets +ve charge. Hence, the membrane is said to be depolarized.
When a stimulus is applied at a site A on the polarised membrane, the membrane at the site A becomes freely permeable to Na+ leading to rapid influx of Na+ followed by the reversal of the polarity at that site. The outer surface of the membrane becomes negatively charged and
the inner side becomes positively charged. The point A becomes depolarised.
The electrical potential difference across the plasma membrane at the site A is called the
action potential or termed as a nerve impulse. At other sites like point B, immediately ahead, the axon membrane has a positive charge
on the outer surface and a negative charge on its inner surface.
Because of this difference in polarity, the current flows on the inner surface from site A to site B. On the outer surface current flows from site B to site A to complete the circuit. Hence, the polarity at the site is reversed, and an action potential is generated at site B.
Thus, the impulse (action potential) generated at site A arrives at site B. The sequence is repeated
along the length of the axon and consequently the impulse is conducted.
Disorders of eye :
1. Myopia or Shortsightedness
2. Hypermetropia or Farsightedness
3. Astigmatism
4. Presbyopia
5. Cataract
1. Human eye has 125 million rod cells and 7 million cone cells. These rods and cones are not evenly distributed.
2. The yellow spot has only cones. As the distance increases from yellow spot towards ciliary body the number of rods increases and number of cones decreases.
3. The blind spot has no rods and no cones because the optic nerve arises from it. Since, there are no photoreceptors thus, there is no perception of the image.
The two cerebral hemispheres are connected by corpus callosum which is 10 cm long and made up of densely packed nerve fibres.
Lobes of cerebral hemisphere : Each cerebral hemisphere has 4 lobes i.e. Frontal lobe, parietal lobe, temporal lobes and occipital lobe.
The advantage of a chemical synapse is that one neurotransmitter impulse can cause the action of multiple muscle cells, for example, whereas an electrical impulse is less versatile.
Moreover in chemical synapses there are different types of messenger neurotransmitters in different synapses permitting different kinds of responses.
1. Resting membrane potential : Plasmamembrane of axon of neuron has +ve charge on outer surface and –ve charge on interior side, this electrical potential across the membrane is called resting membrane potential.
When a neuron is not conducting any impulse i.e. when it is resting, the membrane i s more permeable to K+ and nearly impermeable to Na+.
Similarly, the membrane is impermeable to the negatively charged proteins.
Thus the axoplasm acquires high concentration of K+ and negatively charged proteins and low concentration of Na+.
However the fluid outside the axon contains a low concentration of K+ and high concentration of Na+ . This forms a concentration gradient. These ionic gradients across the resting membrane are maintained by the active
transport of ions by the sodium-potassium pump which transports 3 Na+ outwards for 2 K+ into the cell. As a result, the outer surface of the
axonal membrane possesses a positive charge while its inner surface has a negative charge and is said to be polarised. This electrical potential across the resting membrane is called the Resting Potential.
Conditioned reflex |
Unconditioned reflex |
It is obtained alter the birth of an organism with proper training. It is developed under the action stimulus. It varies with individual. |
It is inherited immediately after birth. It occurs and for this there is no need of previous stimulus. It is specific. |
Pre-ganglionic nerve fibre |
Post-ganglionic nerve fibre |
These fibres come out of central nervous system and pass into ganglion of autonomic nervous system. |
These fibres emerge out from autonomic ganglion and innervates the glands, organs and involuntary muscles. |
Adrenergic nerve fibres |
Cholinergic nerve fibres |
1. The nerve fibres release noradrenalin at their ends. 2. These are mostly sympathetic nerve fibres. |
1. These nerve fibres release acetycholine at their ends. 2. These are mostly parasympathetic nerve fibres. |
The Brain is protected by cranial meninges that are made up of an outer layer called dura mater, a thin middle layer called arachnoid, and an inner layer called pia mater. It is divided into three regions − forebrain, midbrain, and hindbrain.
Forebrain: It is the main thinking part of the brain. It consists of cerebrum, thalamus, and hypothalamus.
(a) Cerebrum: is the largest part of the brain . Cerebrum is divided into two cerebral hemispheres by a deep cleft. These hemispheres are joined by a tract of nerve fibre known as corpus callosum. The cerebral hemispheres are covered by a layer of cells known as cerebral cortex or grey matter. Cerebrum has sensory regions known as association areas. The innermost part of cerebrum gives an opaque white appearance to the layer and is known as the white matter.
(b) Thalamus:
Thalamus is the main centre of coordination for sensory and motor signalling.
(c) Hypothalamus:
It lies at the base of thalamus .
Midbrain:
It is located between the thalamus region of the forebrain and pons region of hindbrain. The cerebral aqueduct passes through the midbrain. Corpora quadrigemia are the four round swelling foind in the dorsal portion of the midbrain.
Hindbrain:
It consists of three regions − pons, cerebellum, and medulla oblongata.
(a) Pons is a band of nerve fibre that lies between medulla oblongata and midbrain. It connects the lateral parts of cerebellar hemisphere together.
(b) Cerebellum ghas a convoluted surface.
(c) Medulla oblongata is the posterior and simplest part of the brain. Its lower end extends in the form of spinal cord and leaves the skull through foramen magnum.
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Eye Structure:
Eyes are spherical structures that consist of three layers.
(a) The outer layer is composed of sclera and cornea.
(i) Sclera - It is an opaque tissue that is usually known as white of the eye. It is composed of a dense connective tissue.
(ii) Cornea - It is a transparent anterior portion of the eye. It lacks blood vessels and is nourished by lymph from the nearby area. It is slightly bulged. It helps in focusing light rays.
(b) The middle layer of the eye is vascular in nature and contains choroid, ciliary body, and iris.
(i) Choroid lies next to the sclera and contains numerous blood vessels that provide nutrients and oxygen to the retina and other tissues.
(ii) Ciliary body: The choroid layer is thin over posterior region and is thick in the anterior portion to form ciliary body. It contains blood vessels, ciliary muscles, and ciliary processes.
(iii) Iris: It is the visible thin coloured portion present at the junction of sclera and cornea.
Lens - The eye contains a transparent, biconvex, and elastic structure just behind the iris. It is known as lens. The lens is held in position by suspensory ligaments attached to the ciliary body. The lens divides the eye ball into two chambers – an anterior aqueous and posterior vitreous chamber.
(c) The innermost nervous coat is the Retina. It contains three layers of cells – inner ganglion cells, middle bipolar cells, and outermost photoreceptor cells.
The receptor cells present in the retina are of two types – rod cells and cone cells.
(a) Rod cells –The rods contain the rhodopsin pigment (visual purple) that is highly sensitive to dim light. It is responsible for twilight vision.
(b) Cone cells –The cones contain the iodopsin pigment (visual violet) and are highly sensitive to high-intensity light. They are responsible for daylight and colour visions.
The innermost ganglionic cells give rise to optic nerve fibre that forms optic nerve in each eye and is connected to the brain.
Ear structure :
Ear is the sense organ for hearing and equilibrium.
It consists of three portions – external ear, middle ear, and internal ear.
1. External ear: It consists of pinna, external auditory meatus, and a tympanic membrane.
(a) Pinna is a sensitive structure that collects and directs the vibrations into the ear to produce sound.
(b) External auditory meatus is a tubular passage supported by cartilage in external ear.
(c) Tympanic membrane is a thin membrane that lies close to the auditory canal. It separates the middle ear from external ear.
2. Middle ear: It is an air-filled tympanic cavity that is connected with pharynx through eustachian tube. Eustachian tube helps to equalize air pressure in both sides of tympanic membrane. The middle ear contains a flexible chain of three middle bones called ear ossicles. The three ear ossicles are malleus, incus, and stapes that are attached to each other.
3. Internal ear: It is also known as labyrinth. Labyrinth is divided into bony labyrinth and a membranous labyrinth. Bony labyrinth is filled with perilymph while membranous labyrinth is filled with endolymph.
Membranous labyrinth is divided into 2 parts.
(a) Vestibular apparatus is a central sac-like part that is divided into utriculus and sacculus. A special group of sensory cells called macula are present in sacculus and utriculus. It also contains three semi-circular canals. The lower end of each semi-circular canal contains a projecting ridge called crista ampularis. Each ampulla has a group of sensory cells called crista. Crista and macula are responsible for maintaining the balance of body and posture.
(b) Cochlea is a long and coiled outgrowth of sacculus. It is the main hearing organ. Cochlea consists of three membranes. The organ of corti, a hearing organ, is located on the basilar membrane that has hair cells.
Write short note on Ear ossicles.
Ear ossicles : The middle ear has 3 tiny bones. These three bones of middle ear are called the ear ossicles. They are malleus, incus and stapes.
i. Malleus is hammer shaped.
ii. Incus is anvil shaped and
iii. Stapes is stirrup shaped.
They are joined with each other and extend from inner part of ear drum to the opening of internal ear called fenestra ovalis.
Functions :
The ear ossicles increase the efficiency of transmission of sound waves to the inner ear.
Retina is the innermost layer. It contains three layers of neural cells – inner ganglion cells, middle bipolar cells, and outermost photoreceptor cells.
The photoreceptor cells present in the retina are of two types – rod cells and cone cells.
(i) Rod cells –The rods contain rhodopsin pigment (visual purple), which is highly sensitive to dim light. It is responsible for twilight vision.
(ii) Cone cells –The cones contain iodopsin pigment (visual violet) and are highly sensitive to high intensity light. They are responsible for daylight and colour visions.
The innermost layer of the ganglionic cells give rise to optic nerve fibre and is connected with the brain.
The point where the optic nerve enters the retina has no photoreceptors and is called the blind spot. At the posterior part, lateral to blind spot, there is a pigmented spot called macula lutea. This spot has a shallow depression at its middle known as fovea. Fovea has only cone cells. They are devoid of rod cells. Hence, it is the place of most distinct vision and has the greatest visual activity or rwesolution.
Write a short bote on the following
(g) Cochlea.
It is the main hearing organ. The cochlea forms three chambers.
(i) Upper − scala vestibule
(ii) Middle − scala media
(iii) Lower − scale tympani
The floor of the scala media is basilar membrane while its roof is Reissner’s membrane. Reissner’s membrane gives out a projection called tectorial membrane. The organ of corti, a hearing organ, is located on the basilar membrane. Organ of corti contains receptor hair cells. The upper scala vestibule and lower scala tympani contain perilymph.
Write a short note on Synapse.
Synapse is a junction between the axon terminal of one neuron and the dendrite of next neuron. It is separated by a small gap known as synaptic cleft.
A synapse is formed by the membranes of a pre-synaptic neuron and a post-synaptic neuron which may or may not be separated by a gap called synaptic cleft. Chemicals involved in the transmission of impulses at chemical synapses are called neurotransmitters.
There are two types of synapses.
(a) Electrical synapse
(b) Chemical synapse
In electrical synapses, the pre and post synaptic neurons lie in close proximity to each other. Hence, the impulse can move directly from one neuron to another across the synapse. This represents a faster method of impulse transmission.
In chemical synapses, the pre and post synaptic neurons are not in close proximity. They are separated by a synaptic cleft. The transmission of nerve impulses is carried out by chemicals such as neurotransmitters.
Organ of Corti : Organ of corti is present on basilar membrane which consists of receptor cells or phonoreceptors and supporting cells.
Receptor Cells : There are 2400 receptor cells. The receptor cells also called hair cells as they contains hair cells that act as auditory receptors. The hair cells are present in rows on the internal side of the organ of corti. The basal end of the hair cell is in close contact with the afferent nerve fibres. A large number of processes called stereo cilia are projected from the apical part of each hair cell. Above the rows of the hair cells is a thin elastic membrane called tectorial membrane.
Supporting Cells : The supporting cells are of two types : Long pillar cells and short phalangeal or Deiters cells.
The amount of light that falls on the retina is cregulated by the change in the diameter of the pupil. The pupils dilate when the light is low so that more light can reach the retina. The diameter of the pupil decreases when there is bright light so that less amount of light reaches the retina.
Forebrain is the main thinking part of the brain. It consists of cerebrum, thalamus, and hypothalamus.
(i) Cerebrum:
Cerebrum is the largest part of the brain. It is divided into two cerebral hemispheres which are joined corpus callosum. The cerebral hemispheres are covered by a layer of cells known as cerebral cortex or grey matter. Cerebrum has sensory regions known as association areas. The innermost part of cerebrum gives an opaque white appearance to the layer and is known as the white matter.
(ii) Thalamus:
Thalamus is the main centre of coordination for sensory and motor signalling. I
(iii) Hypothalamus:
It lies at the base of thalamus and contains a number of centres that regulate body temperature and the urge for eating and drinking.
The hindbrain includes the cerebellum, the pons and the medulla oblongata.
Pons - - They consists of fibre tracts that connect the different regions of the brain.
Cerebellum - It is highly convoluted in structure to adjust a great number of neurons in less space.
Medulla Oblangata - It is the part of the brain that is connected to the spinal cord. The medulla contains centres which control respiration, cardiovascular reflexes and gastric secretions.
Conduction of nerve impulse across a nerve fibre : Conduction of nerve impulse from one nerve fibre to another can be explained in the following points :
1. When the nerve impulse or wave of depolarisation reaches the synaptic knob which has diameter of 50nm, then vesicles of synaptic knobs may release 10,000 acetylcholine into the synaptic cleft by exocytosis under the influence of Ca+2 which diffuse from fluid in synaptic left.
2. The acetylcholine is received by receptors present on the membrane of dendrites of next nerve fibres.
Transmission of Nerve Impulse at Synapse
3. Due to acetylcholine, membrane of dendrites becme depolarised. Immediately acetylcholine splits into acetic acid and choline by an enzyme acetylcholinesterase are present in the membrane of dendrites.
4. Acetic acid + choline return to synaptic knobs and are converted into acetylcholine for reuse.
In case of sympathetic nerve fibres, the nerve impulse travels from one nerve fibre to next by the release of chemical called adrenaline or nor-adrenalin. Thus, these care adrenergic. The adernalin or nor-adrenalin is inactivated by monamine oxidase.
Reverse nerve impulse conduction is not possible because dendrites have no acetylcholine. So, it is one way or unidirectional.
Compare the following
Central neural system(CNS) and peripheral neural system(PNS).
CNS - Central Neural System :
1.It lies on median longitudinal axis of body.
2. It includes brain and spinal cord.
3. The brain is protected by cranium and spinal cord by vertebral column.
PNS : Peripheral Neural System
1. It includes nerves which arise from central nervous system.
2. It includes cranial nerves and spinal nerves.
3. It is not protected by bones.
Resting Potential :
1. The nerve fibre has +ve charge on outside and – ve charge on innerside.
2. It is polarized
3. It is determined by K
Action potential :
1. The nerve fibre has –ve charge on outside and +ve charge on innerside.
2. The nerve fibre is depolarized.
3. It is determined by Na-.
Choroid :
1.It is middle coat of eye ball.
2. It is pigmented connected tissue.
3. Such layers absent
4. Absent
5. It is vascular
Retina :
1. It is inner coat of eye ball.
2. It’s outer layer has pigmented epithelium.
3. It has rods and cones bipolar nerve cells and ganglion cells.
4. It has yellow and blind spots
5. It is sensory.
Give a brief account of mechanism of synaptic transmission
Mechanism of synaptic transmission. Or Conduction of nerve impulse across a nerve fibre : Conduction of nerve impulse from one nerve fibre to another can be explained in the following points :
1. When the nerve impulse or wave of depolarisation reaches the synaptic knob which has diameter of 50nm, then vesicles of synaptic knobs may release 10,000 acetylcholine into the synaptic cleft by exocytosis under the influence of Ca+2 which diffuse from fluid in synaptic left.
2. The acetylcholine is received by receptors present on the membrane of dendrites of next nerve fibres.
Transmission of Nerve Impulse at Synapse
3. Due to acetylcholine, membrane of dendrites became depolarised. Immediately acetylcholine splits into acetic acid and choline by an enzyme acetylcholinesterase are present in the membrane of dendrites.
4. Acetic acid + choline return to synaptic knobs and are converted into acetylcholine for reuse.
In case of sympathetic nerve fibres, the nerve impulse travels from one nerve fibre to next by the release of chemical called adrenaline or nor-adrenalin. Thus, these care adrenergic. The adrenalin or noradrenalin is inactivated by mono-amine oxidase.
Reverse nerve impulse conduction is not possible because dendrites have no acetylcholine. So, it is one way or unidirectional.
Give a brief account of mechanism of vision.
Mechanism of vision Or Working of eye : The eye has two main parts :
(1) Focusing part or Diopteric part : Cornea, aqueous humour, lens and vitreous humour all act as focusing part. The reflected rays from the object fall on the cornea and get refracted. Maximum refraction at aqueous humour lens and vitreous humour. Finally they get converged at the yellow spot. As the rays have some specific energy, so they cause depolarisation of nerve cells.
(2) Receptive part : It has rods and cones, bipolar nerve cells and ganglionated cells. The receptor part after receiving the stimulus of image transmits into the cells of brain which interprets the image as straight.
Give a brief account of mechanism of hearing.
Mechanism of hearing : The sound waves from sounding bodies strike the pinna. The pinna directs the waves into external auditory canal. These sound waves strike tympanum which starts vibrating.
Fig. V. S. Ear of man
(ii) Balance : The equilibrium is maintained by semicircular canals. The equilibrium is of two types :
1. Dynamic equilibrium : It is maintained by cristae present in amplullae of semicircular canals. When the head is rotating, at that time sensory hair get disturbed by moving endolymph. The disturbances are conducted to sensory cells and then to nerve fibres which transmit impulses to brain. It brings the organism in equilibrium.
2. Static equilibrium : When a man is running fast then otolith of maculae lag behind. These otolith come in contact with sensory hair and set up the message which is conducted to the brain and it brings the body in equilibrium.
Role of Na+ in the generation of action potential : Stimulation of an axon increases its membrane permeability to Na+. As a result Na+ ions diffuse across he membrane from the extra cellular fluid (ECF) where their concentration is higher to the interior of the fibre where the concentraion is much lower. The membrane permeability to K+ starts rising so there is simultanous rise in the outward diffusion of K+ from the cell interior having a higher K+concentration. These effects lower the overall cation concentration outside than inside the membrane. Thus, depolarization i.e. charge is reversed in the membrane.
The wave of depolarization spreads. It stimulates adjacent Na+ channel to get activated, so that next part is depolarized but previous part is repolarized. The wave of depolarization spreads in all directions.
Mechanism of generation of light-induced impulse in retina,
1. Light induces dissociation of retinal from opsin and results into changes in structure of opsin.
2. It changes in membrane permeability. Thus potential differences are generated in cones cells.
3. It generates action potential in ganglion cells through dipolar cells.
4. These impulses are transmitted by optic nerves to visual cortex area of brain where impulses are analysed.
Distinguish between impulse conduction in a myelinated nerve fibre and unmyelinated nerve fibre.
Impulse conduction in a myelinated nerve fibre |
Impulse conduction in non myelinated nerve fibre |
1. Conduction of nerve impulse is faster by twnety times. 2. It uses less energy because only nodesare depolarized. 3. It uses less energy because only nodes are depolarizsed. 4. Ion exchange occurs at nodes only. |
1. It is slow. 2. It is smooth. 3. It uses more energy because whole of fibreis depolarized. 4. Ion exchange occurs through out. |
Distinguish between aqueous humor and vitreous humor.
Aqueous humour :
1. Is is found in anterior chamber of eye.
2. It is watery fluid.
3. It is secreted by ciliary processors.
4. It is absorbed by blood.
5. It contains most of diffusible substances of the plasma.
6. Its obstruction may damage retina if it does not flow and causes glaucoma.
Vitreous humour :
1. It is present in posterior chamber of eye.
2. It is jelly like material.
3. It is secreted by retian during development of eye.
4. It is never absorbed or never replaced.
5. It contain 90% of water, vitrein protein, mucopoly saccharide called Hyaluronic acid.
6. It does not cause glaucoma.
Distinguish between
(d) blind spot and yellow spot.
Blind spot :
1. No image is formed.
2. No specific name forits centre.
3. It has no rods arises from it.
4. Optics nerve arises from it.
5. Eye coats absent.
6. It does not lie on principal axis.
Yellow Spot :
1. It is point where image is formed on retina.
2. Its centre is called fovea centralis.
3. It has only cones.
4. Optic, nerve does arise from it.
5. Present
6. It is present on principal axis.
Distinguish between
(e) cranial nerves and spinal nerves.
Cranial Nerves |
Spinal Nerves |
1. They arise from brain. 2. They may be sensory, motor or mixed. 3. They are 12 pairs. 4. They may be unbranched or branched. 5. These are not formed by dorsal and ventral roots. 6. They come out formina of skull. |
1. They arise from spinal cord except 1st pair which develops from medulla oblongata. 2. They are mixed. 3. They are 31 pairs. 4. They are branched, each gives 3 branches. 5. They are formed by dorsal and ventral roots. 6. They emere out between intervertebral foramina. |
Photosensitive compound in human eye is made up of
opsin and Retinal
opsin ans Retinol
transducin and Retinene
guanosine and Retinol
A.
opsin and Retinal
The photosensitive pigment Rhodopsin of the human eye is made up of opsin and Retinal ( the aldehyde form of vitamin-A/ Retinol).
The most abundant intracellular cation is
Na+
Ca2+
H+
K+
D.
K+
Major intracellular cation is K+
Major extracellular cation is Na+
Ca+ play major role in signal transduction pathwayss.
H+ is found in aqueous solution of all acids.
A diagram showing axon terminal and synapse is given. Identify correctly at least two of A-D.
A – Receptor |
C – Synaptic vesicles |
B – Synaptic connection |
D- K+ |
A – Neurotransmitter |
B- Synaptic cleft |
C – Neurotransmitter |
D –Ca2+ |
A.
A – Receptor |
C – Synaptic vesicles |
A - receptor, B - synaptic cleft, C - synaptic vesicles and D - Ca2+
Parts A, B, C and D of the human eyes are shown in the diagram. Select the option, which gives correct identification along with its functions/ characteristics
A - retina - contains photoreceptors -rods and cones
B-blind spot- has only a few rods and cones
C - aqueous chamber - reflects the light which does not pass through the lens
D - choroiditis anterior part forms ciliary body
A.
A - retina - contains photoreceptors -rods and cones
A - retina - contains photoreceptors - rods and cones. The daylight vision is a function of cones and twilight vision is related to rods and cones.
B - Blind spot - photoreceptor cells are not present in this part
C- Aqueous chamber contains a thin watery fluid called aqueous humour
D - Sclera is the external layer of an eye having a dense connective tissue.
Destruction of the anterior horn cells of the spinal cord would result in loss of
Sensory impulses
Voluntary motor impulses
Commissural impulses
Integrating impulses
B.
Voluntary motor impulses
Destruction of the anterior horn cells of the spinal cord would result in loss of voluntary motor impulses. It is because the anterior horn cells (also called anterior grey column), which is the front column of grey matter in the spinal cord contains motor neurons that affect the axial muscles.
In mammalian eye, the 'fovea' is the center of the visual field, where
high density of cones occur, but has no rods.
the optic nerve leaves the eye.
only rods are present
more rods than cones are found.
A.
high density of cones occur, but has no rods.
At the posterior pole of the eye lateral to the blind spot, there is a yellowish pigmented spot called macula lutea with a central pit called the fovea. It is a thinned-out portion of the retina where only the cones are densely packed. It is the point where the visual acuity (resolution) is the highest.
The human hind brain comprises three parts, one of which is
spinal cord
corpus callosum
Cerebellum
hypothalamus
C.
Cerebellum
The hindbrain generally has its anterior roof enlarged to form a pair of cerebellar hemispheres. Its floor is thickened to for the pons anteriorly and the medulla oblongata posteriorly.
Which part of the human ear plays no role in hearing as such but is otherwise very much required?
Eustachian tube
Organ of corti
Vestibular apparatus
Ear ossicles
A.
Eustachian tube
The inner ear contains a complex system called vestibular apparatus, located above the cochlea. It has no role in hearing but is influenced by gravity and movements. Its specific receptors called crista and macula are responsible for maintenance of balance of the body and posture.
How do parasympathetic neural signals affect the working of the heart?
Reduce both heart rate and cardiac output
heart rate is increased without affecting the cardiac output
Both heart rate and cardiac output increase
Heart rate decrease but cardiac output increases
A.
Reduce both heart rate and cardiac output
Parasympathetic neural signal reduces both heart rate and cardiac output, through the postganglionic fibres. These fibres are very short and are cholinergic in nature.
Injury localised to the hypothalamus would most likely disrupt
short term memory
coordination during locomotion
executive function, such as decision making
regulation of body temperature
D.
regulation of body temperature
The hypothalamus performs many functions which are important for the survival and enjoyment of life. it serves as a link between ' mind' and body and between nervous and endocrine system. The hypothalamus is responsible for hormone production. The hormone produced by this area govern body temperature thirst hunger, sleep, circulation rhythm, mood sex drive etc.
This area of the brain also controls the functioning of the pituitary gland. Thus, if any injury localised to the hypothalamus it will disrupt the complete regulation of body temperature and other activities
Which one of the following statements is not correct?
Retinal is the light absorbing portion of visual photopigments
In retina, the rods have the photopigments rhodopsin, while cones have three different photopigments
Retinal is a derivative of vitamin -C
Rhodopsin is the purplish red protein present in rods only
C.
Retinal is a derivative of vitamin -C
Retinal pigment epithelium shields the retina from excess incoming light. It supplies omega- 3 fatty acid and glucose to the retina. The former for building photoreceptive by membranes the latter for energy retinal is supplied by the visual vitamin - A cycle.
The supportive skeletal structures in the human external ears and in the nose tip are examples of
ligament
areolar tissue
bone
cartilage
D.
cartilage
Yellow elastic cartilage is found in external ear or pinna, external auditory canal, eustachian tube, tip of nose, epiglottis and some laryngeal components. It brings about the quick recovery of the organ as soon as the stress is released
Which of the following regions of the brain is incorrectly paired with its function?
Medulla oblongata – homeostatic control
Cerebellum – language comprehension
Corpus callosum – communication between the left and right cerebral cortices
Cerebrum – calculation and contemplation
B.
Cerebellum – language comprehension
Language comprehension includes understanding of speech and written words. It requires input of sensory information (from hearing and vision), processing of the information in different centres of cerebral cortex and the coordination of motor output.
A gymnast is able to balance his body upside down ever in the total darkness because of
cochlea
vestibular apparatus
tectorial membrane
organ of Corti
B.
vestibular apparatus
Vestibular apparatus of membranous labyrinth is an intricate series of inter-connected and fluid-filled canals which regulates balance and spatial orientation in the absence of vision, the movement of body will be regulated only by vestibular apparatus.
The otolith organs (utricle and saccule) regulates linear acceleration and semicircular canals sense rotational acceleration in various directions.
The cochlea, tectorial membrane and organ of Corti are responsible for transduction of sound waves.
The purplish red pigment rhodopsin contained in the rods type of photoreceptor cells of the human eyes is a derivative of
Vitamin -C
Vitamin -D
Vitamin - A
Vitamin - B
A.
Vitamin -C
There are two types of photoreceptor cells of retina, namilyrods and cones. The rods contain a purplish red protein called the rhodopsin or visual purple, which contains a derivative of vitamin - A.
Gland |
Secretion |
Effect on Body |
A |
Oestrogen |
Maintenance of secondary sexual characters |
Alpha cells of islets of Langerhans |
B |
Raise blood sugar level |
Anterior pi- tuitary |
C |
Over secretion leads to gigantism |
A |
B |
C |
Placenta |
Insulin |
Vasopressin |
A |
B |
C |
Ovary |
Insulin | Calcitonin |
A |
B |
C |
Placenta |
Glucagon |
Calcitonin |
A |
B |
C |
Ovary |
Glucagon | Growth hormone |
D.
A |
B |
C |
Ovary |
Glucagon | Growth hormone |
The ovary is the primary female sex organ that produces the female gamete (ovum) and several steroid hormones (ovarian hormones). The two steroid hormones produced by ovary are oestrogen and progesterone. Oestrogens produced by ovary are oestrogen and progesterone. Oestrogens produce wide-ranging actions such as stimulation of growth and activities of females secondary sex organs, development of growing ovarian follicles, appearance of female secondary sex characters (e.g., high pitch of voice, etc.) mammary gland development oestrogens also regulate female sexual behaviour.
Alpha cells of islets of Langerhans of the endocrine pancreas secrete a hormone called glucagon. It is a peptide hormone and plays an important role in maintaining the normal blood glucose levels. It acts mainly on the liver cells (hepatocytes) and stimulates glycogenolysis resulting in an increased blood sugar (hyperglycemia). In addition, this hormone stimulates the process of gluconeogenesis which reduces the cellular glucose uptake and utilisation. Thus, glucagon is a hyperglycemic hormone.
The pars distalis region of pituitary commonly called produced anterior pituitary, Growth Hormone (GH), prolactin (PRL), Thyroid-stimulating Hormone (TSH) Adrenocorticotrophic Hormone (ACTH), Luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Over secretion of GH stimulates the abnormal growth of the body leading to gigantism and low secretion of GH results in stunted growth resulting in pituitary dwarfism.
Select the answer with the correct matching of the structure, its location and function.
Structure |
Location |
Function |
Eustachian |
Anterior part of internal ear |
Equalizes air pressure on either sides of tympanic membrane |
Structure |
Location |
Function |
Cerebellum |
Mid -brain | Controls respiration and gastric secretions |
Structure |
Location |
Function |
Hypothalamus |
Forebrain | Control body temperature, urge for eating and drinking |
Structure |
Location |
Function |
Blind Spot |
Near the place where optic nerve leaves the eye | Rods and cones are present but inactive here |
C.
Structure |
Location |
Function |
Hypothalamus |
Forebrain | Control body temperature, urge for eating and drinking |
Hypothalamus is the part of the sides and floor of the brain derived from the forebrain. lies at the base of the thalamus. The hypothalamus contains a number of centres, which control body temperature, urge for eating and drinking. It also contains several groups of neurosecretory cells, which secrete hormones called hypothalamic hormones.
Which part of human brain is concerned with the regulation of body temperature?
Medulla oblongata
cerebellum
cerebrum
Hypothalamus
D.
Hypothalamus
In the human brain, the hypothalamus is a centre for hunger, thirst sweating, sleep. fatigue, temperature, anger, pleasure, love, hate and satisfaction.
Medulla oblongata contains centre for a heart beat, respiration, digestion, BP, involuntary functions, urination, etc.
Cerebellum regulates posture and balance.
The cerebrum is the centre for intelligence, emotion, will- power, memory consciousness, imagination, etc.
The kind of tissue that forms the supportive structure in our pinna (external ears) is also found in
vertebrae
nails
ear ossicles
tip of the nose
D.
tip of the nose
Yellow fibrous cartilage tissue is found in pinna (external ear). It is also found at the tip of the rose.
Which one of the following is the correct difference between rod cells and cone cells of our retina?
Features |
Rod cells |
Cone cells |
Visual acuity |
High |
Low |
Features |
Rod cells |
Cone cells |
Visual Pigment contained |
Iodeosin |
Rhodopsin |
Features |
Rod cells |
Cone cells |
Overall function |
Vision in poor light |
Colour vision and detailed vision in bright light |
Features |
Rod cells |
Cone cells |
Distribution |
More concentrated in center of retina |
Distributed all over retina |
C.
Features |
Rod cells |
Cone cells |
Overall function |
Vision in poor light |
Colour vision and detailed vision in bright light |
The retina is the neural and sensory layer of the eyeball. A small, oval yellowish area of the retina lying exactly opposite the centre of the cornea is named the macula lutea or yellow spot, which has at its middle a shallow depression the fovea centrails. The foveacentrails has cone cells only. It is devoid or rods and blood vessels. The rods contain the rhodopsin (visual purple) pigment and enable to animals to see in darkness. Therefore. present in large number in nocturanal animals.The cones contain the iodopsin (visual violet) pigment and chiefly concerned with distinction in colour and light vision during daytime.
Cornea transplant in humans is almost never rejected. This is because
its cells are least penetrable by bacteria
It has no blood supply
It is composed of enucleated cells
It is a non-living layer
B.
It has no blood supply
The cornea is the transparent portion that forms t the anterior one -sixth of the eyeball. The cornea admits and helps to focus light waves as they enter the eye, It is avascular, ie, has no blood supply, therefore, cornea transplant in human is almost never rejected.
Which one of the following is a matching pair of a body feature and the animal possessing it?
Post-anal tail - Octopus
Ventral Central nervous system - Leech nervous system
Pharyngeal gill slits absent in embryo
Ventral heart - Scorpion
B.
Ventral Central nervous system - Leech nervous system
The nervous system of leech consisting of ventral central nervous system, peripheral nervous system and sympathetic nervous system.
Bowman’s glands are located in the
proximal end of uriniferous tubules
anterior pituitary
female reproductive system of cockroach
olfactory epithelium of our nose
D.
olfactory epithelium of our nose
Many olfactory glands (Bowman's glands) occur below the olfactory epithelium that secrete mucus over the epithelium to keep it moist.
Which one of the following pairs of structures distinguishes a nerve cell from other types of cells?
perikaryon and dendrites
vacuoles and fibres
flagellum and modulloary sheath
nucleus and mitochondria
A.
perikaryon and dendrites
A nerve cell consists of cell body (perikaryon) containing the nucleus, Nissl granules, dendrites and an axon. These are specialized cells.
Ultrasound of how much frequency is beamed into human body for sonography?
30-45 MHz
15-30 MHz
1-15 MHz
45-70 MHz
C.
1-15 MHz
In sonography (ultrasound imaging) inaudible high frequency of sound waves in the range of 1-5 MHz are used.
Biological organisation starts with
submicroscopic molecular level
cellular level
organismic level
atomic level
A.
submicroscopic molecular level
Biological organisation starts with submicroscopic molecular level, where four types of molecules, i.e. carbohydrates, lipids, proteins and nucleic acid are organised into organelles of cell.
Which one of the following statements is correct?
Neurons regulate endocrine activity, but not vice versa
Endocrine glands regulate neural activity, and nervous system regulates endocrine glands
Neither hormones control neural activity nor the neurons control endocrine activity
Endocrine glands regulate neural activity, but not vice versa.
A.
Neurons regulate endocrine activity, but not vice versa
The autonomous nervous system regulates the secretion of glands whereas the glands do not regulate the nervous system.
Bowman's glands are found in
olfactory epithelium
external auditory canal
cortical nephrons only
juxtamedullary nephrons
A.
olfactory epithelium
Bowman's glands (olfactory glands) occur below the olfactory epithelia. Their ducts open on the olfactory epithelial surface. These glands secrete watery mucus to protect and keep the epithelium moist.
Which one of the following not act as a neurotransmitter?
Acetylcholine
Epinephrine
Nor epinephrine
Cortisone
D.
Cortisone
Cortisone is a corticosteroid that is itself biologically inactive and is formed naturally in the adrenal gland (adrenal cortex) from the active hormone cortisol. Cortisol promotes the synthesis and storage of glucose and important in the normal response to stress, suppresses inflammation and regulates deposition of fat in body.
Acetylcholine is a neurotransmitter secreted from the nerve endings.
Epinephrine and nor-epinephrine are secreted from the medulla of adrenal gland and these also acts as neurotransmitter.
Which of the following structures or regions is incorrectly paired with its functions?
Medulla oblongata : Controls respiration and cardiovascular reflexes
Limbic system: consists of fibre tracts that interconnect different regions of brain; controls movement.
Corpus callosum: band of fibres connecting system: left and right cerebral hemispheres.
Hypothalamus: production of releasing hormones and regulation of temperature,the hunger and thirst.
B.
Limbic system: consists of fibre tracts that interconnect different regions of brain; controls movement.
Limbic system (emotional motor system) is emotional brain. It controls all emotions in our body but not movements. It is located in the core of the brain and includes the amygadla, hippocampus and hypothalamus.
The transparent lens in the human eye is held in its place by
ligaments attached to the ciliary body
ligaments attached to the iris
smooth muscles attached to the ciliary body
smooth muscles attached to the iris
A.
ligaments attached to the ciliary body
Lens in the human eye is held in its place by suspensory ligaments attached to the ciliary body.
Nissl bodies are mainly composed of
Proteins and lipids
DNA and RNA
Free ribosomes and RER
Nucleic acids and SER
C.
Free ribosomes and RER
Nissl granules are present in the cyton and even extend into the dendrite but absent in axon and rest of the neuron.
Nissl granules are in fact composed of free ribosomes and RER. They are responsible for protein synthesis.
Match the following columns.
Column I | Column II | ||
A | Sacral nerves | 1. | 1 Pair |
B | Thoraic nerves | 2. | 8 Pair |
C | Cocygeal nerves | 3. | 7 Pairs |
D | Cervical nerves | 4. | 12 Pairs |
5. | 5 Pairs |
A | B | C | D |
4 | 1 | 3 | 2 |
A | B | C | D |
5 | 3 | 1 | 2 |
A | B | C | D |
5 | 4 | 1 | 1 |
A | B | C | D |
2 | 5 | 3 | 1 |
C.
A | B | C | D |
5 | 4 | 1 | 1 |
Pick the hormone which is not secreted by human placenta.
hCG
hPL
Prolactin
Oestrogen
C.
Prolactin
Prolactin is secreted by a pituitary gland, whereas the hCG, hPL and oestrogen are secreted by the human placenta.
Which of the following statement is correct in relation to the endocrine system?
Adenohypophysis is under direct neural regulation fo the hypothalamus
Organs in the body like a gastro-intestinal tract, heart, kidney and liver do not produce any hormone.
Non-nutrient chemicals produced by the body in trace amount that act as inter-cellular messanger are known as hormones.
Releasing and inhibitory hormones are produced by the pituitary gland
C.
Non-nutrient chemicals produced by the body in trace amount that act as inter-cellular messanger are known as hormones.
Endocrine cells are present in different, parts of the gastro-interntinal tract, e.g. gastrin secretin, GIP. Atrial wall of our heat secretes a peptide hormone called ANF (Atrial Natriuretic Factor). RH/IH is produced by the hypothalamus. Adenohypophysis is not directly under neural control, it is under the control of hypothalamic hormones, brought by portal system.
In the central nervous system, myelinated fibres form the ….., while the non-myelinated fibre cells form the ……
Grey matter, white matter
White matter, grey matter
Ependymal cells, neurosecretory cells
Neurosecretory cell, ependymal cells
B.
White matter, grey matter
The grey matter is composed of nerve cells, nerve fibres and neuroglia, which are non-myelinated while white matter is composed of mostly with myelinated axons.
Lens of eyes is derived from
Ectoderm
Mesoderm
Endoderm
Both (b) and (c)
A.
Ectoderm
Eye lens is derived from ectoderm.
Schneiderian and tympanic membrane respectively belongs to
Ear and nose
Ear and eye
Ear and ear
Nose and ear
D.
Nose and ear
Schneiderian and tympanic membranes respectively belongs to nose and ear.
During the transmission of nerve impulse through a nerve fibre, the potential on the inner side of the plasma membrane has which type of electric charge?
First negative then positive and again back to negative
First positive than negative and continue to be negative
First negative then positive and continue to be positive
First positive then negative and again back to positive
A.
First negative then positive and again back to negative
During the transmission of nerve impulse through a nerve fibre, the potential on the inner side of the plasma membrane has first negative charge, then positive and again negative by repolarisation.
Parkinsonism is related with
Brain
Spinal Nerve
Cranial Nerves
All of these
A.
Brain
Parkinsonism is naming after James Parkinson, is caused by the various lesion in the extra-pyramidal motor system of the brain. It frequently occurs in old persons or in the patients, which are treated with antipsychotic lungs.
If the threshold for hearing increasing 1000 times, the hearing loss is
40 decibels
50 decibels
60 decibels
None of these
D.
None of these
A decibel is a measure of the ratio between two sound stimuli. The decibel level of a sound that a normal human can hear and is calculated using the formula.
Intensity (in decibels) = 10 x log (sound/threshold)
Therefore, the intensity of a sound that is 1000 times, thresh hold is 30 Decibels.
Sympathetic nervous system induces
Heartbeat
Secretion of digestive juice
Secretion of saliva
All of the above
A.
Heartbeat
Medulla of brain has two regions affecting heart rate.
(i) Cardiac inhibitory centre.
(ii) Cardiac accelerator centre
Sensory nerves originating from the accelerator centre run parallel to the spinal cord and enter the sino-artial node. Stimulation by these nerves, which are the part of the sympathetic nervous system causes an increase in heartbeat.
Which cranial nerve has the highest number of branches?
Facial nerve
Trigeminal
Vagus nerve
None of these
C.
Vagus nerve
Vagus nerve has five branches:
(i) Superior laryngeal nerve
(ii) Recurrent laryngeal nerve
(iii) Cardiac nerve
(iv) Pneumogastric nerve
(v) Depresser nerve
The junction between the axon of one neuron and the dendrite of the next is called
Junction point
A synapse
A joint
Constant bridge
B.
A synapse
The end-to-end position of the axon of the one neuron and the dendrites of another neuron called synapse.
Most neutrons do not actually touch other neurons with which they communicate, instead, there is a minute space, separating these two called the synaptic cleft.
Vetebrate brain differentiates from
Endoderm
Mesoderm
Ectoderm
Blastoderm
C.
Ectoderm
The brain is the centre of the nervous system in all vertebrates and most invertebrate animals. The neural plate of ectoderm forms the brain, spinal cord and nerves.
Human ear ossicles are
incus and stapes
stapes
incus, malleus and stapes
incus and malleus
C.
incus, malleus and stapes
Ear ossicles are three small non- supporting bones of body, present in middle ear of human. They are responsible for transmitting and amplifying vibrations received from tympanum.
Ear ossicle | Shape | Size |
Malleus | Hammer | Largest ear ossicle |
Incus | Anvil | Medium sized ear ossicle |
Stapes | Stirrup | Smallest ear ossicle |
'Adaptation' of eyes in dark is due to
depletionof vision pigment in rods
depletion of vision pigment in cones
repletion of vision pigment in rods
repletion of vision pigment in cones
C.
repletion of vision pigment in rods
Two types of photoreceptor cells are present in retina, ie, rods and cones.
(i) Rods : These cells are active in dark rhodopsin, a vision pigment is present in rods. In strong light, rhodopsin is bleached due to splitting of its two components, ie, scotopsin and retinal.
(ii) Cones : These cells are active in strong light. Iodopsin a pigment is present in cones. These cells produce hare coloured image in bright light.
In parasympathetic nervous system, which of the following is released?
Epinephrine
Norepinephrine
Serotonin
Acetylcholine
D.
Acetylcholine
Autonomic Nervous System (ANS) automatically regulates the activities of smooth, cardiac muscles and glands. This coordination is involuntary. It is of two types:
(i) Sympathetic ANS : It shows sympathy, ie, increases the function and expenditure of energy takes place. Preganglionic nerve secretes acetylcholine and post-ganglionic nerve secretes sympathetin.
(ii) Parasympathetic ANS : It provides relaxation, comfort, pleasure at the time of rest and conservation of energy takes palce. Post- ganglionic nerve secretes acetylcholine.
The velocity of conduction of nerve impulse in frog is
300 m/s
same as of electricity
faster than sound
30 m/s
D.
30 m/s
The velocity of conduction of nerve impulse in frog is 30 metres per second.
Tree of life is
arbor vitae
pons Varolii
organ of Corti
diencephalon
A.
arbor vitae
Arbor vitae is the tree like appearance of white matter in the cerebellum.
Eustachian canal connects
middle ear with external ear
middle ear with internal ear
external ear with internal ear
pharynx with middle ear
A.
middle ear with external ear
The fucntion of Eustachian tube is to equalise air pressure on both (external and middle ear) the sides of tympanic membrane. Thus, it connects middle ear with external ear.
From outer to inside the sequence of three bones present in the middle ear of mammals is
malleus, stapes and incus
stapes, malleus and incus
malleus, incus and stapes
incus, malleus and stapes
C.
malleus, incus and stapes
The middle ear cavity in mammals characteristically contains a chain of three little bones or ear ossicles extending between the tympanic membrane and the fenestra ovalis. These are called malleus (hammer), incus (anvil) and stapes (stirrup) because of their characteristic shapes.
The cavity of diencephalon is known as
I ventricle
II ventricle
III ventricle
iter
C.
III ventricle
Diencephalon is located between cerebral hemispheres above and midbrain below. Its cavity is known as the third ventricle or diocoel. It is connected to each lateral ventricle of cerebral hemisphere by foramen of Monro, seperately.
Aqueous and vitreous humour are divided by
lens
iris
retina
optic nerve
A.
lens
Lens is a transparent, biconvex, elastic structure that bends light waves as they pass through its surface. The lens separates the aqueous and vitreous humours.
Autonomic nervous system affects
reflex actions
sensory organs
internal organs
None of these
C.
internal organs
Autonomic Nervous System controls and co-ordinates the involuntary activities of various internal organs. This system is divided into two parts:-
(a) Sympathetic Nervous System
(b) Parasympathetic Nervous System
In a man, abducens nerve is injured. Which one ofthe following functions will be affected?
Movement of the eye ball
Swallowing
Movement of the tongue
Movement of the neck
A.
Movement of the eye ball
Abducens (abducent) nerve is a cranial nerve which originates from the ventral surface of medulla oblongota. It innervates the lateral rectus muscle of eye ball. It is a motor nerve and controls the movements of the eye ball. Hence, if this nerve is injured in a human, movement of eye ball will be affected.
Neural canal is present in
humerus
tibia-fibula
vertebral column
cranial bones
C.
vertebral column
A typical vertebra has a centrum or body and neural arch. The hole formed by the neural arch
is the vertebral foramen. The vertebral foramina of all vertebrate form the vertebral canal or neural canal.
If dorsal nerve of spinal cord is broken down then its effect is
no impulse is transmitted
impulse is transmitted but slowly
impulse is transmitted fast
no effect on impulse
A.
no impulse is transmitted
spinal cords consist of various types of neurons which basically include sensory neuron (resides on the dorsal side), Motor neuron(resides in ventral side) and interneuron(resides inside spinal cord especially in grey matter).
If the dorsal spinal cord is broken then it affects the functioning of the sensory neuron.
One of the examples of the action of the autonomous nervous system is
knee-jerk response
pupillary reflex
swallowing of food
peristalsis of the intestines
D.
peristalsis of the intestines
Peristalsis of intestine is related with Autonomous Nervous System whereas knee- jerk response, pupillary reflex and swallowing of food are related to reflex action.
Which one of the following depresses brain activity and produces feelings of calmness, relaxation and drowsiness?
Valium
Morphine
Hashish
Amphetamines
A.
Valium
Valium deficiency brain activity and produces feeling of calmness, relaxation and drowsiness.
Ventricles are related to
heart only
brain only
both 'a' and 'b'
none of these
C.
both 'a' and 'b'
Ventricles are related to both heart and brain. Mammalian heart is four chambered. The upper two chambers known as right and left auricle and the lower as right and left ventricles. In brain there are four ventricles. Ventricle Ist and II (lateral ventricles) are cavities of two cerebral hemispheres. IIIrd ventricle (diocoel) is cavity of diencephalon and IV ventricle (metacoel) is cavity of medulla oblongata.
Schwann cell is found around
axon
cyton
dendrite
dendron
A.
axon
All multicellular animals contain elongated nerve cells, called neurons. Each neuron has a cell body, axon and smaller processes called dendrites. An axon is the process of a nerve cell that carries impulses away from it. It runs parallel to one another and each is surrounded along its whole length by series of Schwann cells. They may have myelin sheath.
Which part of retina consists of only cones?
Fovea centralis
optic nerve
Blind spot
Orasmata
A.
Fovea centralis
Fovea centralis is a small, central pit composed of closely packed cones in the eye. Ability for vision is highest in the fovea.
Optic nerve is a bundle of more than 1 million nerve fibres that carry visual messages. It is composed of retinal ganglion cell axon and glial cells.
Blind spot is a small portion of the visual field of each eye that corresponds to the position of the optic disk within the retina. There are no photoreceptors in the optic disk and therefore, no image detection takes place.
Reflex action involves
spinal cord
cerbellum
medulla oblongata
optic lobe
A.
spinal cord
Reflexes are classified as the spinal reflexes and the cranial reflexes.
Spinal reflexes are so called because their basic neural path leads through spinal nerves and spinal cord. Reflexes at the spinal level have the purpose of removing the animal from harmful stimuli.
Which of the following is the part of mid brain of rabbit?
Diencephalon
Cerebrum
Corpora quadrigemina
None of the above
C.
Corpora quadrigemina
The dorsal part of mid brain (mesencephalon) is in the form of two pairs (i.e., four) of spherical optic lobes (corpora quadrigemina) located behind the pineal body optic lobes are reduced merely as reflex centres of visual and auditory.
Now-a-days cornea transplantation is very popular. The reason is that it
is easy to preserve
transplanted very easily
can be easily obtained
does not link with blood supply and immune system
D.
does not link with blood supply and immune system
Cornea transplantation is very popular these days because the cornea has no blood supply, so it is away from the immune system of the body.
Unidirectional transmission of a nerve impulse through nerve fibre is due to the fact that
nerve fibre is insulated by a medullary sheath
sodium pump starts operating only at the cyton and then continues into the nerve fibre
neurotransmitters are released by dendrites and not by axon endings
neurotransmitters are released by the axon endings and not by dendrites.
D.
neurotransmitters are released by the axon endings and not by dendrites.
A synapse occurs where the axon of one neuron (the pre-synaptic neuron) meets the dendrite of another (the post-synaptic neuron). At the tip of the pre-synaptic axon is a button shaped swelling called a synaptic knob, inside which are numerous mitochondria and vesicles packed with a substance called a neurotransmitter which at the time of nerve impulse conduction diffuse across the space and bind to receptors in the membrane of the post-synaptic cell. This opens ion channels in the post-synaptic membrane resulting in a change in its membrane potential and in the consequent generation of a nerve impulse.
Cornea transplant in humans is almost never rejected. This is because
it is composed of enucleated cells
it is a non-living layer
its cells are least penetrable by bacteria
it has no blood supply
D.
it has no blood supply
Cornea is a tranparent layer of tissue continuous with sclerotic that forms the front part of vertebrae eye over the iris and lens. It refracts light waves entering the eye onto lens. Cornea is avascular (ie, it has no blood supply). It is one of the first organs to be successfully transplanted because it lacks blood vessels.
Assertion : All motor neurons are efferent neurons.
Reason : Motor neurons conduct nerve impulses from the spinal cord to the brain.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false.
If both assertion and reason are false
D.
If both assertion and reason are false
Afferent neurons are sensory that carry nerve impulses from sensory stimuli towards the central nervous system and brain, while efferent neurons are motor neurons that carry neural impulses away from the central nervous system and towards muscles to cause movement.
Given is the diagrammatic representation of the sectional view of cochlea. Select the correct option regarding it.
A - Organ of corti-responsible for maintenance of balance of the body and posture.
B- Scala vestibuli-filled with perilymph that ends at the oval window.
C- Scala tympani-terminates at the round window which opens to the middle ear.
D- Basilar membrane - nerve impulses are generated against it.
C.
C- Scala tympani-terminates at the round window which opens to the middle ear.
B-Scala vestibuli-the upper bony passage of the cochlea.
C-Scala tympani-perilymph-filled cavities in the inner ear of the human
D-Basilar membrane-stiff structural element that separates two liquid-filled tubes that run along the coil of the cochlea, the scala media and the scala tympani
Assertion: The optic nerves leave the eye at the point called blind spot.
Reason: Only cone are densely packed at the blind spot, hence is the name.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
C.
If assertion is true but reason is false.
The nerve fibres from all parts of the retina converge to leave through a point called blindspot. It is the place in the visual field that corresponds to the lack of light detecting photo receptor cells on the optic disc of the retina.
Organ of Corti is found in
heart
kidneys
inner ear
nasal chamber
C.
inner ear
Organ of Corti are found in cochlear channel (internal ear) and are responsible for hearing. Ear is concerned both with hearing and balance, semicircular canals are responsible for balance when body is in motion.
Which of the following nerves arises from organ of Corti?
Olfactory nerve
Cochlear nerve
Abducens nerve
None of these
B.
Cochlear nerve
The organ of Corti consists of outer hair cells, inner hair cells, inner pillar cells, outer pillar cells, tunnel of Corti, phalangeal cells (cells of Deiters), cells of Hensen and cells of Claudius. The sensory hair project from the outer ends of the hair cells into the scala media, while from the inner end of the cells nerve fibres arise, which unite to form the cochlear nerve.
Assertion : Connective tissue inside the brain is essential for conduction of nerve impulse.
Reason : Connective tissue hold together the nerve cells of brain.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
D.
If both assertion and reason are false
Connective tissue consists of variously shaped cells lying in an extracellular material called matrix. It joins one tissue to another in the organs. Connective tissue is absent inside the central nervous system i.e. brain and spinal cord and thus has no function in the conduction of nerve impulse.The nerve cells of the brain and spinal cord are held together by supporting cells called neuroglia cells.
One common example of simple reflex is
tying your shoe laces while talking to another person and not looking at them
watering of mouth at the sight of a favourite food
climbing up a stairs in dark without stumbling
closing of eyes when strong light is flashed across them.
D.
closing of eyes when strong light is flashed across them.
Simple or unconditional reflexes are present in an individual right from birth. They are specific, predictable, purposeful and have survival value, e.g. breast feeding and swallowing in newly born babies and blinking of eyes are examples of unconditioned reflexes.
(a), (b) and (c) are the examples of conditional reflexes and are not present at birth but develop later in life through learning habit.
Injury to vagus nerve in humans is not likely to affect
tongue movements
gastrointestinal movements
pancreatic secretion
cardiac movements.
A.
tongue movements
Vagus nerve arises from the side of medulla oblongata. It innervates the larynx, trachea, oesophagus, stomach, lungs, heart and intestines. It is a mixed nerve. It controls the visceral sensations and visceral movements, i.e., heart beat, respiratory movements, peristalsis, sound production, etc. Movement of the tongue is controlled by hypoglossal nerve as it innervates the muscles of the tongue.
Which of the following is an eye disease?
Hepatitis
Measles
Glaucoma
Bronchitis
C.
Glaucoma
Glaucoma is a condition in which loss of vision occurs because of an abnormally high pressure in the eye. This is also known as primary glaucoma and is of two types- acute and chronic simple.
Hepatitis is an inflammation of the liver caused by viruses, toxic substance or immunological abnormalities.
Measles or Rubeola disease is an acute infectious eruptive viral disease of childhood caused by specific virus of the group myxoviruses. It is the infection of respiratory tract and conjunctiva which is transmitted by contact, fomite and droplet methods.
Bronchitis is the inflammation of the bronchi.
Which match is true?
Vitamin deficiency disease | Vitamin | Source |
Severe bleeding | Tocopherol | Milk, egg |
Anaemia | Ascorbic acid | Lemon, orange |
Night blindness | Retinol | Carrot, milk |
Sterility | Calciferol | Milk, butter |
C.
Night blindness | Retinol | Carrot, milk |
Night blindness is the inability to see in dim light or at night. It is due to disorder of the cells in the retina that are responsible for vision in dim light and can result from dietary deficiency of vitamin A (retinol).
Name | Sources | Effect of deficiency |
Vitamin C/ Ascorbic acid | Citrus fruits such as lemon, orange etc. Green vegetables, Potatoes etc. | Scurvy is characterised by wound healing an dgrowth retardation etc. |
Vitamin D/ Ergocalciferol and Cholecalciferol | Synthesized in skin cells in sunlight. Also found in butter, liver, kidneys, egg yolk etc. | Rickets, a disorder of children of 6 months to 2 years. |
Vitamin E/ Tocopherol | Green vegetables, oils, egg yolk, wheat, animal tissues | Reversible sterility in female. |
The black pigment in the eye which reduces the internal reflection is located in
retina
iris
cornea
sclerotic
A.
retina
The black pigment in the eye which reduces the internal reflection is known as retina. It is the inner most coat of the eyeball and it is a thin, light sensitive nervous layer. The external coat of the eyeball is known as sclerotic but in front of the sclerotic, there is a transparent connective tissue called cornea. Iris is the pigmented part present in front of choroid.
Hearing impairment affects which part of brain?
Frontal lobe
Parietal lobe
Temporal lobe
Cerebellum
C.
Temporal lobe
Temporal lobe is one of the main divisions of the cerebral cortex in each hemisphere of the brain, lying at the side within the temple of the skull and separated from the frontal lobe by a cleft, the lateral sulcus. Areas of the cortex in this lobe are concerned with the appreciation of sound and spoken language.
Assertion : Astigmatism is due to uneven curvature of lens.
Reason : It is treated with cylindrical lenses.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
B.
If both assertion and reason are true but reason is not the correct explanation of assertion
Astigmatism is a defect of vision in which the image of an object is distorted. It is either in the vertical or the horizontal axis, because not all the light rays come of a focus on the retina. Some parts of the object may be in focus but light from other parts may be focused in front of or behind the retina. This is usually due to abnormal curvature of the cornea and/ or lens whose surface resembles part of sphere. The defect can be corrected by wearing cylindrical lenses, called toric contact lens which produce exactly the opposite degree of distortion and thus cancel out the distortion caused by the eye itself.
Assertion: Rhabdome is present in Palaemon.
Reason: Rhabdome has an important role in digestion
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
C.
If assertion is true but reason is false
Inner ends of cone cells lie upon an elongated, spindle shaped rod, the rhabdome. Rhabdome is secreted and surrounded by a group of seven elongated retinal cells. Rhabdome , and retinal cells together form the receptor region of eye.
Given below is a table comparing the effects of sympathetic and parasympathetic nervous system for four feature (a-d). Which one feature is correctly described
Feature | Sympathetic nervous system | Parasympathetic nervous system |
Salivary glands | Stimulate Secretion | Inhibit Secretion |
Pupil of the eye | Dilate | Constricts |
Heart rate | Decreases | Increases |
Intestinal peristalsis | Stimulates | Inhibits |
B.
Pupil of the eye | Dilate | Constricts |
Sympathetic and parasympathetic nervous system are the parts of autonomic nervous system. Autonomic nervous system is a part of peripheral nervous system that supplies stimulation via motor nerves to the smooth and to cardiac muscles (the involuntary muscles) and to the glands of the body. The activity of the ANS is controlled principally by the medulla oblongata and hypothalamus of brain. Sympathetic and parasympathetic nervous system tend to work antagonistically on the same organ.
Feature | Sympathetic nervous system | Parasympathetic nervous system |
a) Salivary glands b) Pupil of the eye c) Heart rate d) Intestinal peristalsis |
Inhibit Secretion Dilate Increases Inhibits |
Stimulate Secretion Decreases Increases Stimulates |
Examine the diagram of the two cell types A and B given below and select the correct option
A B
Cell A is the rod cell found evenly all over retina
Cell A is the cone cell more concentrated in the fovea central is
Cell B is concerned with colour vision in bright light
Cell A is sensitive to low light intensities
A.
Cell A is the rod cell found evenly all over retina
The retina contains two types of photoreceptors, rods and cones. The rods are more numerous, some 120 million, and are more sensitive than the cones. However, they are not sensitive to color. The 6 to 7 million cones provide the eye's color sensitivity and they are much more concentrated in the central yellow spot known as the macula. In the center of that region is the " fovea centralis", a 0.3 mm diameter rod-free area with very thin, densely packed cones.
A person who shows unpredictable moods, outbursts of emotion, quarrelsome behaviour and conflicts with others is suffering from
borderline personality disorder (BPD)
mood disorder
addictive disorder
schizophrenia.
A.
borderline personality disorder (BPD)
Borderline personality disorder (BPD) is a serious mental illness. Borderline describing, a personality disorder characterized by unstable and intense relationships, exploiting and manipulating other people, rapidly changing moods, recurrent suicidal or self injuring acts & a prevasive inner feelings of emptiness and boredom.
A mood disorder is a condition where the prevailing emotional moods is distorted or inappropriate to the circumstances. Addiction is a state of dependence produced by the habitual taking of drugs, alcohol, etc.
Schizophrenia is a group of severe mental disorders characterized by disturbances of languages and communications, thought disturbances that may involve distortion ofreality, misperceptions, delusions and hallucination, mood changes and withdrawl etc.
Unidirectional transmission of a nerve impulse through nerve fibre is due to the fact that
nerve fibre is insulated by a medullary sheath
sodium pump starts operating only at the cyton and then continues into the nerve fibre
neurotransmitters are released by dendrites and not by axon endings
neurotransmitters are released by the axon endings and not by dendrites.
D.
neurotransmitters are released by the axon endings and not by dendrites.
Neurotransmitters are molecules that fit like a lock and key into a specific receptor. The receptor is located on the next cell in the line. Therefore, nerve impulses cannot travel in the opposite direction, because nerve cells only have neurotransmitter storage vesicles going one way, and receptors in one place.
The total number of nitrogenous bases in human genome is estimated to be about
3.5 million
35 thousand
35 million
3.1 billion.
D.
3.1 billion.
Genome size is usually stated as the total number of base pairs; the human genome contains roughly 3 billion base pairs.
A person is wearing spectacles with concave lenses for correcting vision. While not using the glasses, the image of a distant object in his case will be formed
on the blind spot
behind the retina
in front of the retina
on the yellow spot
C.
in front of the retina
As the person uses spectacles having concave lens, he must be suffering from myopia or short-sightedness. Here the eyeballs become elongated, so that parallel rays are focussed in front of retina.
Myopia is an eye disorder where light focuses in front of retina. This causes distant objects appear normal. It is also known as short- sightedness.
Cochlea of mammalian internal ear is concerned with
hearing
balance of body posture
both (a) and (b)
perception changes of atmospheric pressure
A.
hearing
The cochlea is a portion of the inner ear that looks like a snail shell (cochlea is Greek for snail.) The cochleareceives sound in the form of vibrations, which cause the stereocilia to move. The stereocilia then convert these vibrations into nerve impulses which are taken up to the brain to be interpreted.
The part of an eye which acts like a diaphragm of a photographic camera is
pupil
iris
lens
cornea
B.
iris
The iris of the eye is the thin, circular structure made of connective tissue and muscle that surrounds the pupil. The color of our eyes is determined by the amount of pigment in the iris apart from this the iris acts like the diaphragm of a camera and controls the size of the pupil. One muscle within the iris constricts the pupil in bright light (full sunlight, for example), and another iris muscle dilates (enlarges) the pupil in dim lighting and in the dark.
The dendrite carries impulses
towards the cyton
away from cyton
across the body
from one neuron to another
A.
towards the cyton
Dendrites Receive STIMULUS (Action Potentials) and carry IMPULSES from the ENVIRONMENT or from other NEURONS AND CARRY THEM TOWARD THE CELL BODY. However AXON – A Long Fibre that CARRIES IMPULSES AWAY FROM THE CELL BODY. Each neuron has only ONE AXON. The Axon Ends in a series of small swellings called AXON TERMINALS.
Cerebrospinal fluid is present
beneath the pia mater
between piamater and arachnoid
between arachnoid and duramater
between duramater and cranium
C.
between arachnoid and duramater
CSF occupies the subarachnoid space (between the arachnoid mater and the pia mater) and the ventricular system around and inside the brain and spinal cord. It fills the ventricles of the brain, cisterns, and sulci, as well as the central canal of the spinal cord.
Cranium is made up of
8 bones
12 bones
10 bones
16 bones
A.
8 bones
The human skull is generally considered to consist of twenty-two bones—eight cranial bones and fourteen facial skeleton bones. In the neurocranium these are the occipital bone, two temporal bones, twoparietal bones, the sphenoid, ethmoid and frontal bones.
Arbor-vitae is composed of
grey matter
neurogleal cells
white matter
all of the the above
A.
grey matter
The arbor vitae (Latin for 'tree of life') is the cerebellar white matter, so called for its branched, tree-like appearance. In some ways it more resembles a fern and is present in both cerebellar hemispheres. It brings sensory and motor information to and from the cerebellum.
In cerebellum strips of white matter profusely ramify into the folds of grey matter. This system of branched strips of white matter within each cerebellar hemisphere is called Arbor-vitae'.
Human brain has greater development of
cerebrum
cerebellum
optic lobes
medulla oblongata
A.
cerebrum
Cerebrum is the most prominent and developed region of the brain in humans. It is the site of functions as vision, hearing, touch, smell, voluntary muscle activity, speech and memory.
The cerebellum receives information from the sensory systems, the spinal cord, and other parts of the brain and then regulates motor movements. It coordinates voluntary movements such as posture, balance, coordination and speech.
Optic lobe function is to process and integrate incoming optical data from the eyes, detecting visual information like shapes and movements.
Medulla oblongata process information to and from the spinal cord and the cerebellum. It helps regulate breathing, heart and blood vessel function, digestion, sneezing and swallowing.
The 'end organs of Ruffini' are receptors of :
heat
cold
pressure
touch
A.
heat
'End organs of Ruffini' are elongated and somewhat spindle-shaped, having two or more interwinding and encapsulated dendrites of sensory neurons. They occur in the deeper layer of dermis. These are thermoreceptor organ ie., are sensitive to heat.
Which of the following part of human brain is associated with integration of sympathetic and parasympathetic activities ?
Cerebrum
Neopallium
Hypothalamus
Medulla oblongata
C.
Hypothalamus
Hypothalamus is thickened floor and sides of the third ventricle of the forebrain. It integrates the autonomic nervous system, with centre for sympathetic and parasympathetic control.
The unidirectional transmission of a nerve impulse through nerve fibre is due to :
neurotransmitters are released by axon endings
neurotransmitters which are released by dendrites
nerve fibre which is insulated by a medullary sheath
sodium pump which starts operating into the nerve fibre
A.
neurotransmitters are released by axon endings
Unidirectional transmission of a nerve impulse, through nerve fibre is due to that neurotransmitters are released by the axon endings.
In the myopia eye defect, the rays of light :
do not enter the eye at all
meet at a focus in front of the retina
come to a focus at back of retina
come to a focus in between retina and iris
B.
meet at a focus in front of the retina
In myopia, the eye-ball is too long and the retina is too far from the lens, and the light rays converge at a point in front ofthe retina and are diverging when they reach it. It result in a blurred image.
Sensory receptor of warmth located principally at the tip of fingers is known as :
Weber's organ
organ of Giraldes
Ruffini's corpuscles
organ of Zuckerkandl
C.
Ruffini's corpuscles
Ruffini's corpuscles are encapsulated sensory nerve endings found in subcutaneous tissue of finger tips and thought to mediate sense, of warmth.
Foramen magnum is situated in
buccal cavity
base of skull
left auricle
vertebrae
B.
base of skull
The foramen magnum is a large oval opening (foramen) in the occipital bone of the skull in humans and various other animals. It is one of the several oval or circular openings (foramina) in the base of the skull.
The genes and splenium in brain are associated with
cerebellum
crebrum
medulla oblongata
vermis
B.
crebrum
Corpus callosum is the band of white neurons present between both cerebral hemisphere of cerebrum and connect them on medial surface. Anterior part of corpus callosum is calledgen while its posterior part is called splenium.
Scala vestibuli is connected with
fenestra rotundus
fenestra ovalis
scala tympani
scala media
C.
scala tympani
The vestibular duct or scala vestibuli is a perilymph-filled cavity inside the cochlea of the inner ear that conducts sound vibrations to the cochlear duct. It is separated from the cochlear duct by Reissner's membrane and extends from the vestibule of the ear to the helicotrema where it joins the tympanic duct.
The scala vestibuli and scala tympani are filled with perilymph. At the apex of cochlear duct (scala media), scala vestibuli and scala tympani communicate by a narrow junction called helicotrema.
The friction between the eyelids and the cornea is avoided by the secretion of
lachrymal glands
conjunctiva and eyelids
hardarian glands
Meibomian glands
D.
Meibomian glands
Meibomian glands are also called tarsal glands and are modified sebaceous gland on the edges of eyelids, these keep a thin film of oil over the cornea which acts as lubricant.
Which of the following element is responsible for Minamata disease?
Hg
Pb
Cd
Fe
A.
Hg
Minamata disease is caused due to mercury. It is a disease of the central nervous system (CNS). It occurs due to poisoning caused by long- term consumption, in large amounts, of fish and shellfish from Minamata Bay. Mercury, is changed to water soluble dimethyl, mercury, which undergoes biomagnification. This disease is characterized by diarrhoea, haemolysis, impairment of various senses numbness of lips tongue, limbs etc.
Which statement is incorrect for ion-channels?
They are proteins
Movement through them is simple diffusion
Movement through them is from high to low concentration
All ions pass through the same type of channel
D.
All ions pass through the same type of channel
Ion channels are protein channels. Substances can move by simple diffusion directly along these cannels from high concentration to low concentration. Many of the protein channels are highly selective for transport of one or more specific ion.
Part of the brain concerned with the muscular movement is
cerebellum
thalamus
Hippocampus
temporal lobe of cerebrum
A.
cerebellum
Cerebellum is well developed part of brain in humans. It consists of two lateral cerebellar hemispheres and central worm shaped part, the vermis. It controls rapid muscular activities such as running, typing and even talking.
In human, corpus callosum connects
the two optic lobes
bone and muscle
the two cerebral hemispheres
two lobes of pituitary gland
C.
the two cerebral hemispheres
The cerebrum (largest and most complex part of human brain) consists of left and right hemispheres connected by a large bundle of myelinated fibres the corpus callosum and other smaller fibre bundles.
Broca's area of speech is present in
frontal lobe
parietal lobe and partially in temporal lobe
temporal lobe
temporal and occipital lobe
A.
frontal lobe
The motor speech area (also called Broca's motor speech area) lies in the frontal lobe of brain. In the frontal lobe creative ideas occur.
Which part of the human brain is largest
Cerebellum
Thalamus
Cerebrum
Medulla
C.
Cerebrum
The cerebrum is the largest part of the human brain, making up about two-thirds of the brain's mass. It has two hemispheres, each of which has four lobes: frontal, parietal, temporal and occipital.
What is cochlear microphonics?
Cochlear microphonic is the electrical potential generated in the hair cells of the organ of Corti in response to acoustic stimulation.
What is axon reflex?
Axon reflex is a neuron reflex in which an afferent impulse travels along a nerve fibre away from the cell body until it reaches a branching, where it is diverted to an end organ without entering the cell body. It does not involve a complete reflex arc and therefore it is not a true reflex.
Which of the following is not related to the autonomic nervous system?
Peristalsis
Digestion
Excretion
Memory and learning
D.
Memory and learning
The Autonomic Nervous System or ANS or visceral nervous system is the part of the peripheral nervous system that acts as a control system functioning largely below the level of consciousness and controls visceral functions. It affects heart rate, digestion, respiration rate, salivation, perspiration, diameter of the pupils, micturition (urination) and sexual arousal.
Comprehension of spoken and written words take place in the region of
association area
motor area
Wernicke's area
Broca's area
D.
Broca's area
The production of language is linked to the Broca's area. It controls mator functions involved with speech production. People who have damage this area of the brain can understood words but struggle to put them together in speech.
Which one of the following cranial nerves is carying the nerve fibres originating from the Edinger-Westphal nucleus?
Oculomotor
Trochlear
Abducens
Vagus
A.
Oculomotor
Edinger-Westphal nucleus is also known as the accessory oculomotor nucleus. It is the accessory parasympathetic cranial nerve nucleus of the oculomotor nerve (cranial nerve III), supplying the constructing muscles of the iris.
How many laminae are present in the grey matter of spinal cord?
Four
Six
Eight
Ten
D.
Ten
In the grey matter of spinal cord, ten laminae are present. The grey matter is sub- divided on the basis of neuronal cells with similar function.
Colour blindness is due to defect in
cones
rods
rods and cones
rhodopsin
A.
cones
Colour blindness results in absence or malfunctioning of one or more of the three types of cone cells responsible for colour vision.
The amount of CSF in the cranial cavity
500 mL
140 mL
1 litre
1.5 mL
B.
140 mL
All the ventricles ofbrain and central canal of spinal cord contain lymph-like extracellular fluid called cerebrospinal fluid (CSF). The total amount of CSF present in and around central nervous system is 80-150 mL. CSF contains glucose, proteins, lactic acid, urea, Na+, K+, Ca2+, Mg2+, Cl-, HCO3- and some WBCs.
Electric potential of the brain is recorded by
CT scan
Sphygmomanometer
ECG
EEG
D.
EEG
The electrical activity of exposed animal brain is recorded by Electroencephalograph (EEG). It is useful to find out whether the person is alert awake or asleep.
The part of the brain where the centre for hunger and thirst is located is
cerebrum
hypothalamus
cerebellum
medulla oblongata
B.
hypothalamus
Hypothalamus is the main coordinating and control centre for autonomic nervous system. It is centre of thermoregulation, appetite, thirst, hunger and satisfaction.
The reflex arc, which is made of two neurons is known as
monosynaptic reflex arc
disynaptic reflex arc
polysynaptic reflex arc
asynaptic reflex arc
A.
monosynaptic reflex arc
Reflex arc is the arrangement of neurons in the pathway that always passes through central nervous system. The axon of one neuron ends on the dendrites of next neuron. Such a junction is called synapse. Monosynaptic reflex arc has only two neurons, ie, sensory and motor which forms one synapse.
Which of the following does not act as a neurotransmitter
Acetylcholine
Epinephrine
Glutamic acid
Tyrosine
D.
Tyrosine
Tyrosine is a precursor to neurotransmitters and hormones. In dopaminergic cells in the brain, tyrosine is converted to L-DOPA by the enzyme tyrosine hydroxylase (TH). TH is the rate-limiting enzyme involved in the synthesis of the neurotransmitter dopamine.
Which centre is stimulated during increase in body temperature?
Anterior hypothalamus
Posterior hypothalamus
Limbic system
Red nucleus
A.
Anterior hypothalamus
Hypothalamus is the main coordinating and control centre for autonomic nervous system. Its anterior part is thermoregulatory centre. Hence, hypothaluamus is called thermostat of the body.
Which of the following substances can cure Parkinson's disease?
GABA
Acetylcholine
Dopamine
Glutamic acid
C.
Dopamine
Parkinson's disease is caused by dopamine deficiency. Dopamine is a neurotransmitter. These are chemicals released from a presynaptic neuron that interact with specific receptor sites of a post synaptic neuron.
Movement of tongue muscle is controlled by
facial nerve
trigeminal nerve
hypoglossal nerve
vagus nerve
C.
hypoglossal nerve
There are twelve cranial nerves in mammals. Hypoglossal (the 12th) cranial nerve is responsible for movement of neck and tongue. It contains both sensory and motor fibres.
Fcaial nerve (7th nerve) helps in contracting and producing facial expressions.
Trigeminal nerve carries sensation from a person's face to brain.
Vagus nerve is the longest nerve of the body. It helps to regulate many critical aspects of human physiology such as, heart rate, blood pressure etc.
Which function will be lost due to damage of occipetal lobe?
Hearing
Speech
Vision
Memory
C.
Vision
Cerebral hemisphere of forebrain is divided into frontal parietal, temporal and occipital lobes. The occipital lobe is where your eyes see and interpret what is seen.
Vegus nerve is a
mixed X cranial nerve
mixed XI cranial nerve
mixed X thoracic nerve
sensory X cranial nerve
A.
mixed X cranial nerve
Vagus nerve is the tenth cranial nerve of mixed nature. It innervates to the chest, abdomen and heart.
The number of spinal nerves in human is
10 pairs
12 pairs
43 pairs
31 pairs
D.
31 pairs
Man has 31 pairs of spinal nerves. These are
(a) Cervical 8 pairs in neck
(b) Thoracic- 12 pairs in thorax
(c) Lumbar- 5 pairs in upper part of abdomen
(d) Sacral 5 pairs in lower part of abdomen
(e) Coccygeal tail nerve.
Frog has 10 pairs of spinal nerves, while rabbit has 37 pairs of spinal nerves.
Third and fourth ventricles of the brain are connected by
aqueduct of Sylvious
foramen of Monro
foramen of Magnum
corpus callosum
A.
aqueduct of Sylvious
The connecting passage between III ventricle (diocoel), IV ventricle and optocoels (cavities of optic lobes) is called aqueduct of sylvius. Foramen of Monro connects lateral ventricles with III ventricle or diocoel.
During synaptic transmission of nerve impulse, neurotransmitter (P) is released from synaptic vesicles by the action of ions (Q). Choose the correct P and Q.
P - Acetylcholine; Q - Ca2+
P - Acetylcholine; Q - Na+
P - GABA; Q - Na+
P - Cholinesterase; Q - Ca2+
A.
P - Acetylcholine; Q - Ca2+
Ca2+ is responsible for the release of neurotransmitter acetylcholine from axon terminal by rupturing the synaptic vesicle.
Identify the origin of sympathetic nerve fibres and the location of their ganglia.
They arise from thoracolumbar region of spinal cord and form ganglia just beside the vertebral column
They arise from thoracocervical region of spinal cord and form ganglia just beside the vertebral column
They arise from cranio-sacral region of spinal cord and from ganglia very close to effector organ
They arise from thoracolumbar region of spinal cord and form ganglia very close to effector organ
A.
They arise from thoracolumbar region of spinal cord and form ganglia just beside the vertebral column
The sympathetic nervous system (SNS) is part of the autonomic nervous system (ANS), which also includes the parasympathetic nervous system (PNS). The sympathetic nervous system activates what is often termed the fight or flight response. It arises from the thoracolumbar region of spinal cord and form ganglia just beside the vertebral column.
Among the following characteristics, indicate the correct combination applicable to conditional reflex.
I. Acquired by practice or learning
II. Non acquired by birth.
III. Does not abolish by lack of practice
IV. Participation of cerebral cortex
V. Originates spontaneously
I, II and III
I, II and IV
I and IV
II, III and V
B.
I, II and IV
Conditioned or acquired reflexes are those reflex actions that are not present at birth but develop later in life through learning or experience. However, these are liable to change, disappear (due to lack of practice) or reappear. Cerebral cortex (grey matter) takes part in conditional reflexes.
A diagram showing axon terminal and synapse is given. Identify correctly at least two of A-D
A - Receptor; C - Synaptic vesicles
B - Synaptic connection; D - K+
A - Neurotransmitter; B - Synaptic cleft
C - Neurotransmitter; D - Ca2+
A.
A - Receptor; C - Synaptic vesicles
A - receptor
B - synaptic cleft
C - synaptic vesicles
D - Ca2+
Parts A, B, C and D of the human eyes are shown in the diagram. Select the option, which gives correct identification along with its functions/characteristics
A - retina - contains photoreceptors - rods and cones
B - blind spot - has only a few rods and cones
C - aqueous chamber - reflects the light, which does not pass through the lens
D - choroidits anterior part forms ciliary body
A.
A - retina - contains photoreceptors - rods and cones
A - Retina-contains photoreceptors - rods and cones. The daylight vision is function of cones and twilight vision is related to rods.
B - Blind spot-Photoreceptor cells are not present in this part.
C - Aqueous chamber contains a thin watery fluid called aqueous humour.
D - Sclera is the external layer of eye having dense connective tissue.
Which excitatory neurotransmitter is involved in the transmission of impulse at the neuromuscular junction?
Epinephrine
Serotonin
Acetylcholine
Glycine
C.
Acetylcholine
Acetylcholine is an organic molecule that act as a neurotransmitter in many organisms including humans. It is one of the many neuro transmitters in. Autonomic Nervous System (ANS). It acts on both peripheral and central nervous system (i.e., PNS and ANS). It behaves as an excitatory neurotransmitter at neuro muscular junction in skeletal muscle. It also has an inhibitory effect which lowers heart rate in cardiac tissue.
Which area of cerebral cortex is responsible for the interpretation of speech?
Broca's area
Wernicke's area
Premotor area
Association area of sensory cortex
B.
Wernicke's area
Wernicke's area or Wernicke's speech area is one of the two parts of the cerebral cortex linked to the interpretation and understanding of speech, while Broco's area (another area of cerebral cortex) is associated with the production of speech. It basically control the flow of words from brain to the mouth.
Broca's area or the Broca area is a region in the frontal lobe of the dominant hemisphere. It is linked to speech production.
The premotor cortex is an area of motor cortex lying within the frontal lobe of the brain just anterior to the primary motor cortex.
Association cortex is the cerebral cortex outside the primary areas. It is essential for mental functions that are more complex than detecting basic dimensions of sensory stimulation, for which primarysensory areas appear to be necessary.
Proximal convoluted tubule of nephron is responsible for
filtration of blood
maintenance of glomerular filtration rate
selective reabsorption of glucose, amino acid, NaCl and water
reabsorption of salts only
C.
selective reabsorption of glucose, amino acid, NaCl and water
The cells of Proximal Convoluted Tubule (PCT) have numerous microvilli which increases the surface area available for reabsorption. Mostly 65% of reabsorption takes place within the PCT only. It acts as a major site for the selective reabsorption of glucose, amino acids, water and different ions (such as hydrogen ions, bicarbonate ions, potassium ions, etc.).
Which of the following statements are true for 'Motor cortex'?
I. It is located in the frontal lobe of cerebral cortex.
II It contains pyramidal cells.
III. It is responsible for all visual functions.
IV. It is essential for our thought processes.
V. It stimulates wakefulness.
VI. It regulates voluntary muscular movements.
I, II, III and V
II, III, IV and V
II, IV, V and VI
I, II, IV and VI
A.
I, II, III and V
Motor cortex is the region located in the frontal lobe of the cerebral cortex which regulates the voluntary muscular movements based on our thought process such as planning, control and execution. It contains pyramidal cells or pyramidal neuron which are the primary excitation units.
Which one of the following acts solely as an inhibitory neurotransmitter?
Norepinephrine
Gamma () amino butyric acid
Acetylcholine
Dopamine
B.
Gamma () amino butyric acid
-aminobutyric acid is the chief inhibitory neurotransmitter in the mammalian central nervous system. It helps in reducing neuronal excitability throughout the nervous system. In humans it is also directly responsible for the regulation of muscle tone.
Nor-epinephrine, also called nor-adrenaline is a neurotransmitter released by adrenergic nerve terminals in the oentral nervous system.
Acetylcholine is the neurotransmitter produced by neurons referred to as cholinergic neurons.
Dopamine is a neurotransmitter that plays a number of important roles in the human brain and body.
The bundle of axons in the central nervius system is known as
nerve
ganglion
tract
neuron
C.
tract
The bundle of axons in the central nervons system is known as tract. Neuronal tract connects one part of the nervous system with another.
In the peripheral nervous system a bundle of axons is called a nerve.
A ganglion is a nerve cell cluster or a group of nerve cell bodies located in the autonomic nervous system.
A neuron (nerve cell) is on electrically excitable cell that processes and transmits information through electrical and chemical signals via synapses.
Which one of the followings is the functional unit of hearing?
Utricle
Organ of Zuckerkandl
Organ of Corti
Vestibular apparatus
C.
Organ of Corti
The organ of Corti is the functional unit of hearing and contains the sound receptors that convert mechanical vibration into nerve impulses. It contains the receptors that transform mechanical vibrations into nerve impulses. These are located in the basilar membrane of the organ of corti thus making it the functional unit of hearing.
Which one of the followings is not a refractive medium of the eye?
Lens
Vitreous humour
Aqueous humour
Pupil
D.
Pupil
Pupil is not considered as a refractive medium of the eye. The eye contains various refractive media within it which effectively bend and refract the incoming light, so that it is all focused upon a certain point on the retina. This refraction can only occur with the use of refractive media and in some cases refractive media which can change their respective refractive power (the lens).
Which of the following pairs of cranial nerves is/are of mixed category?
Glossopharyngeal and hypogrossal
Trigeminal and abducens
Trigeminal and facial
Glossopharyngeal and vagus
C.
Trigeminal and facial
D.
Glossopharyngeal and vagus
Mixed nerves contain both sensory and motor fibres
Name | Composition | Functions |
Glossopharyngeal (IX) | Motor and sensory (mixed) | It serves the pharynx for swallowing. |
Vagus | Mixed | Sensations from visceral (internal) organs and parasympathetic motor regulation of visceral organs |
Hypoglossal | Motor | Serves muscles of the tongue |
Trigeminal | Mixed | Sensory from face and mouth; motor to muscles of mastication |
Facial | Mixed | Serves the muscles of facial expression, lacrimal glands and salivary glands |
Abducens | Motor | Serves the lateral rectus eye muscle |
Myelin sheaths
are abundant in nervous system of non- vertebrates
consists largely of lipids
has a low electric resistance
allows the continous conduction of impulse
B.
consists largely of lipids
Myelin sheaths consists largely of lipids and has a high electrical resistance. These are abundant in vertebrates and allows the saltatory conduction of impulse.
Pacinian corpuscles found in the skin are sensitive to
touch
pressure
temperature (hot and cold)
vibrations
D.
vibrations
Pacinian corpuscles are found in the skin, joints, tendons, muscles and gut area and consist of the endings of a single neuron surrounded by many layers of connective tissue. These receptors respond to pressure.
Which of the following statement is true for maculae found in the internal ear of humans?
It is present in ampullae of semicircular ducts
These are three in number
Each macula contains calcarious ear stones called oto lith.
All of above
C.
Each macula contains calcarious ear stones called oto lith.
Except c, all statements are incorrect, Maculae is present in utricle and saccule. These are two in number. Along with cristae, it is concerned with balance.
Myelin sheaths
are abundant in the nervous system of non-vertebrates
consists largely of lipids
has a low electric resistance
allow the continous conduction of impulse
B.
consists largely of lipids
Myelin sheaths consists largely of lipids and has a high electrical resistance. These are abundant in vertebrates and allows the saltatory conduction of impulse.
Which of the following characteristic is not seen in a person suffering from schizoprenia?
Auditory hallucinations
Split personality
False beliefs
Lack of motivation
B.
Split personality
Schizoprenia is a mental disorder. It is characterised by abnormal social behaviour and failure to recognize what is real. Common symptoms include false beliefs, unclear or confused thinking, auditory halluicinations, reduced social engagement and emotional expression and lack of motivation. This condition does not imply split personality, it often implies splitting of mental functions.
Utriculus of internal ear is
lower chamber related with equilibrium
lower chamber related with receiving sound waves
upper chamber related with receiving sound waves
upper chamber related with equilibrium
D.
upper chamber related with equilibrium
Utriculus of internal ear is an upper chamber related with equilibrium. The maculae present in utriculus and sacculus have an otolithic membrane overlaying sensory cells. This maintains the equilibrium.
The most appropriate definition of neuroglial cells are
non-sensory and supporting cells
secretory cells
sensory and supporting cells
non-sensory supporting or secretory cells
A.
non-sensory and supporting cells
The neuroglial cells are non-excitable supporting and protective component of nervous tissue.These are of the following types astrocytes, oligodendrocytes and microglia in the central nervous system fibrous connective tissues in peripheral nervous system respectively.
Match the disease in column I with their characteristic symptoms in column II caused in brain.
Column I | Column II |
A. Parkinson's disease | 1. Refers to lack of muscle coordination. Damage to cerebellum is a characteritic symptom |
B. Dyslexia | 2. Refers to the destruction of myelin sheath of neuron of CNS |
C. Alaxia | 3. It is characterized by tremors and progressive rigidity of limbs caused by degeneration of neurons |
D. Multiple sclerosis | 4. Involves an inability of an individual to comprehend the written language |
A - 2; B - 4; C - 3; D - 1
A - 3; B - 2; C - 1; D - 4
A - 4; B - 3; C - 2; D - 3
A - 3; B - 4; C - 1; D - 2
D.
A - 3; B - 4; C - 1; D - 2
Column I | Column II |
A. Parkinson's disease | 3. It is characterized by tremors and progressive rigidity of limbs caused by degeneration of neurons |
B. Dyslexia | 4. Involves an inability of an individual to comprehend the written language |
C. Alaxia | 1. Refers to lack of muscle coordination. Damage to cerebellum is a characteritic symptom |
D. Multiple sclerosis | 2. Refers to the destruction of myelin sheath of neuron of CNS |
Match the parts of the human brain with their functions.
Column I | Column II |
A. Cerebrum | 1. Controls the pituitary |
B. Cerebllum | 2. Controls vision and hearing |
C. Hypothalamus | 3. Controls the rate of heart beat |
D. Midbrain |
4. Seat of intelligence 5. Maintains body posture |
A - 5; B - 4; C - 2; D - 1
A - 4; B - 5; C - 2; D - 1
A - 5; B - 4; C - 1; D - 2
A - 4; B - 5; C - 1; D - 2
D.
A - 4; B - 5; C - 1; D - 2
Column I | Column II |
A. Cerebrum | 4. Seat of intelligence |
B. Cerebellum | 5. Maintains body posture |
C. Hypothalamus | 1. Controls the pituitary |
D. Midbrain | 2. Controls vision and hearing |
Ivan Pavlov performed experiments on
origin of life
cardiac reflexes
simple reflexes
conditioned reflexes
D.
conditioned reflexes
Conditioned reflex is an automatic response established by training to an ordinarily neutral stimulus. They were first demonstrated in 1920s by the Russian physiologist I.P. Pavlov. He found that the sight and smell of food reflexly cause flow of saliva in hungry animals.
From acrosome, which secretes
hyaluronic acid
hyaluronidase
TSH
fertilizin
B.
hyaluronidase
Acrosome secrets a lytic enzyme hyaluronidase, which help in the penetration of ovum.
In motor neuron the impulse following in which direction?
In two direction
In one drection
In all direction
None of the above
A.
In two direction
Motor neurons are efferent neurons and are located in CNS. The impulse acts in two direction. It carry impulses from the brain and spinal cord to muscles or glands. hen a stimulus is received by a sensory neuron, the impulse (or message) is carried through fibrous extensions called dendrites to the cell body.
Which of the following is not a mental disorder?
Epilepsy
Neurosis
Psychosis
Plague
D.
Plague
Plague is also known as black death (due to dark blue areas of skin caused by haemorrhages). It is caused by a rod-shaped Gram negative bacterium, Yersinia pestis. This bacterium occurs in blood of rat and transmits from one rat to other by the rat flea, Xenopsylla cheopis.
Proximal and distal convoluted tubules are parts of a
nephron
oviduct
vas deferens
caecum
A.
nephron
A nephron is made of two parts Malpighian corpuscle and tubule. Tubule consists of Proximal Convoluted Tubule (PCT), loop of Henle and distal convoluted tubule.
The proximal tubule is the segment of the nephron in kidneys which begins from the renal pole of the Bowman's capsule to the beginning of loop of Henle. The distal convoluted tubule (DCT) is a portion of kidney nephron between the loop of Henle and the collecting tubule.
Cranial nerve showing maximum branching is
trigeminal
vagus
optic
facial
B.
vagus
Vagus or pneumogastric is a mixed nerve, which originates from side of medulla oblongata. It has 5 branches
(i) superior laryngeal
(ii) recurrent laryngeal
(iii) cardiac
(iv) pneumogastric
(v) depressor.
In human eyes, colour perception is done by
rod cells only
cone cells only
Both (a) and (b)
choroid laver cells
B.
cone cells only
Cones are responsible for the perception and differentiation of colours. They produce sharp, coloured image in bright light
Rods are helpful for visualization in dim light and is responsible for black and white vision.
During the conduction of nerve impulse, the action potential is the result of movement of
Na+ from intracellular fluid to extracellular fluid
Na+ from extracellular fluid to intracellular fluid
Na+ towards both directions
None of the above
B.
Na+ from extracellular fluid to intracellular fluid
Nerve impulse is a wave of bioelectric disturbance that passes along a nerve during conduction of an excitation. The electrochemical potential developed during depolarisation is called action potential during which Na+ from extracellular fluid move the intracellular fluid.
Which are the longest cells in the body of man ?
Muscle cells of legs
Bone cells
Nerve cells
None of the above
C.
Nerve cells
The longest cell in human body is neurons or nerve cells. They are located in the base of spinal cord.
Which of the following nerve is purely motor nerve?
vagus
facial
abducens
trigeminal
C.
abducens
Abducens is an example of a pure motor nerve. It arises from the anterior end of medulla oblongata in the vertebrate brain to supply the posterior rectus muscle of each eye ball.
Which of the following part of a neuron is covered by fatty sheath ?
axon
cyton
dendrite
node of Ranvier
A.
axon
Nerve fibres which conducts impulse away from the cell body are termed as axons. They are thinner than dendrites and may be several meter long. Axons consists of an axis slender (axoplasm), surrounded in most vertebrates by fatty myelin sheath.
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