Cochlear microphonic is the electrical potential generated in the hair cells of the organ of Corti in response to acoustic stimulation.

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.

Circulation of substances such as bile salts, which are absorbed from the intestine and carried to the liver, where they are secreted into the bile and again enter the intestine, is known as enterohepatic circulation of bile salt.

It is important because 95% of the salt gets recycled and each of the bile salt molecule gets reused about 20 times.

The juxtaglomerular apparatus is a microscopic structure in the kidney, which regulates the function of each nephron. It is named for its proximity to the glomerulus, it is found between the vascular pole of the renal corpuscle and the returning distal convoluted tubule of the same nephron. 

It is important in regulating blood pressure, body fluid and electrolytes.

Telomere is the end of chromosome, which consists of tandemly repeated short sequences of DNA. Each time a cell divides some sequences of the telomere are lost, eventually (after 60-100 divisions in an average cell) the cell dies. Replication of telomeres is directed by telomerase, an enzyme consisting of RNA and protein that is inactive in normal cells of higher organisms.