[A] : Acetylchoiine allows a nerve cell to com- municate chemically with a muscle cell at neuromuscular junction.
[R]: Acetyicholine diffuses across the junc- tion and binds to some receptors on mem- brane of muscle cell.

Assertion:When an impules arrives at the end plate of an axon, the vesicals releases acetylcholine into the myoneural junction Reason:Acetylcholine diffuses across the nerve-muscle gap ,binds to receptors on the sarcolemma which gets depolarized and results in cantraction of the muscle fibre.

Assertion (A) Chemical messenger gives message to the cell without entering the cell. Reason (R) Chemical messenger is received at the binding site of receptor proteins.

Assertion (A) Chemical messenger gives message to the cell without entering the cell. Reason (R) Chemical messenger is received at the binding site of receptor proteins.

Assertion (A) : Chemical messenger gives message to the cell without entering the cell. Reason (R) : Chemical messenger is received at the binding site of receptor proteins.

How many of the given statements are true? A. The dry surface of the skin and the moist surface of the buccal cavity, are lined by compound epithelium. B.Cuboidal epithelium facilitates diffusion across the epithelium. C. Intercalated discus are the cell junctions between the cardiac muscle cells. D. Skeletal muscle fibers can be located in the biceps muscle. E. In a bone, osteocytes are located in lacunae.

How many of the given statements are true? A. The dry surface of the skin and the moist surface of the buccal cavity, are lined by compound epithelium. B. Cuboidal epithelium facilitates diffusion across the epithelium. C. Intercalated discs are the cell junctions between the cardiac muscle cells. D. Skeletal muscle fibers can be located in the biceps muscle. E. In a bone, osteocytes are located in lacunae.

(A) Chemical messenger gives message to the cell without entering the cell. (R) Chemical messenger is received at the binding site of receptor proteins.

Assertion: In cardiac muscle tissue, the communication junctions (intercalated discs) at some fusion points allow the cells to contract as a unit. Reason: When one cell of cardiac muscle tissue recieves a signal to contract, its neighbours are also stimulated to contract.