Question

Which one is responsible for muscle contraction and nerve impulse transmission ?

• A. $F{e}^{2+}andF{e}^{2+}$
• B. $C{a}^{2+}andC{a}^{2+}$
• C. $M{g}^{2+}$
• D. Both B and C

Answer 1

The correct option is B $C{a}^{2+}andC{a}^{2+}$

A neuromuscular junction is a chemical synapse between the motor neuron terminal and muscle fiber. In this region, the impulse is transmitted from motor neuron to muscle which leads to its constriction. When an action potential is generated in motor neuron it travels through salutary conduction to the terminal part of the neuron . Once it reaches here, it ( action potential ) leads to the influx of Ca++ ions inside by voltage-gated calcium channel. The Ca++ influx causes the presynaptic vesicles containing neurotransmitter acetylcholine to fuse with the plasma membrane, releasing acetylcholine in the synaptic cleft. This leads to opening of Na gated channel in muscle fiber and further contraction and conduction of nerve impulse.

Hence answer is B.