Question

Describe the neuronal control of skeletal muscle contraction and explain the effects of calcium channel blockers on blood pressure.

Answer 1

Neural control of skeletal contraction.

Contraction of muscle begins when the nervous system generates a signal.The signal is nothing but action potential that travels through nerve called motor neuron.This action potential reaches the neuromuscular junction ,it is the place where motor nerve reaches the skeletal muscle cell.And when it reaches the neuromuscular junction releases a chemical messenger called neurotransmitter called acetylcholine which binds to the receptors of muscle fibres and open channels and causes influx of sodium ions,influx of sodium ions causes release of stored calcium ions.Calcium ions binds to troponin and then troponin moves the tropomysoin from actin binding site and and myosin will bind to the actin binding site and and pulls the thin filaments that is actin filament towards the M line and requies ATP .As the mysoin contains two heads one head bind to actin and other bind to ATP and pulls the thin filaments and causes contraction of skeletal muscle.

Effects of Calcium channel blockers on blood pressure.

Calicium channel blockers reduce the blood pressure.They block the voltage sensitive Calicium channels emmbeded in the blood vessels,cardio myocytes and the calcium channel in vascular smooth muscle and causes relaxation of arterial smooth muscles.Afterload on the heart also decreases and causes coronary vasodilation.Due to the blockage of calcium by Calcium channel blockers there is no calicium for contarction so the vessel cause dilation and decrease the blood pressure.