Question

B C). F Fotch G I Anind A [Choose) B

Answer 1

The following picture depict the physiological of neuromuscular junction and how action potential propogates through the motor neuron and reach muscle fibers to cause contraction. The events in sequencial order are -

A- action potential moves down motor neuron.

B- voltage gated calcium ions open in axon terminal and exocytosis of acetylcholine occurs.

C- acetylcholine diffuse across the synapse of the neuromuscular junction.

D- acetylcholine binds with muscarinic cholinergic receptors.

E- A calcium ATPase is always active. (It is important because it will continuously allow influx of calcium ions. And as long as calcium are there , the muscle will remain in contracted state).

F- action potential move across the sarcolemma and down the T-tubule.

G- strech gated calcium channel open causing influx of calcium into the cytosol of muscle cell.

H- the action potential moves across the sarcolemma and down the T-tubule.

I- calcium is released form sarcoplasmic reticulum through the opening of voltage gated calcium ions

J- calcium diffuses through the cytosol and binds to troponin.

And finally contraction of muscle occur.