Study the following and identify the incorrect statements.

I. Muscles of the iris end ciliary body are the smooth muscles of mesodermal origin.

II. Slow and sustained involuntary contractions of smooth muscles are called spasms.

III. Quiescent mononucleate myogenic cells of skeletal muscles are called pericytes.

IV. The skeletal muscle fibre is multinucleate and is a synctium.

• I, IV

• II, IV

• III, IV

• I, III

D.

I, III

Statement I, II and III are incorrect. But this is not given in the options. The above statements can be corrected as follows:

(I) Muscles of the iris and ciliary body are ectodermal in origin.

(II) A sudden involuntary contraction of muscles is called spasm. Slow, involuntary and sustained muscles contraction of hand, toes and feet is called dystonia.

(III) Pericytes are contractile cells surrounding endothelial cells of capillaries also known as mural cells or rouget cells.