Question

chapter 17

I just want to know which is Electrical and which is Muscle Contraction

Answer 1

Answer:-

Electrical Muscle Contraction

Electrical muscle contraction is also known as neuro muscular electrical stimulation or electromyostimulalation. It is the elicitation of muscle contraction using electric impulses..It has received an increasing amount of attention in the last few years for many reasons. It can be utilized as a strength training tool for healthy subjects and athletes. It could be used as a rehabilitation and preventive tool for partially or totally immobilized patients, could be utilized as a testing tool for evaluating the neural and muscular function in vivo.It could be used as a post-exercise recovery tool for athletes. The impulses are generated by a device and are delivered through electrodes on the skin near to the muscles being stimulated.The electrodes are generally pads that adhere to the skin.The impulses mimic the action potential that comes from the central nervous system, causing the muscles to contract.

Muscle Contraction

The Actin and Myosin filaments within the sarcomeres of muscle fibers bind to create cross-bidges and slide past one another,creating a contraction.This is called muscular contraction.Muscle contraction is initiated by a signal sent by the central nervous system(CNS) via motor neuron.A motor neuron along with the muscle fibres connected to it constitute a motor unit.The junction between a motor neuron and sacrolemma of the muscle fibre is called the neuro muscular junction or motor-end plate. A neural signal reaching reaching this junction releases a neurotransmitter which generates an action potential in the sarcolemma..This spreads through the muscle fibre and causes the release of calcium ions into the sarcoplasm .Increase in Ca++ level leads to the binding of Ca with a sub unit of troponin on actin filaments and thereby remove the masking of active sites for myosin.Utilising the energy from ATP hydrolysis, the myosin head now bind to the exposed active sites on action to form a cross bridge.Tis pulls the attached actin filaments towards the centre of "A" band.The "Z" line attached to these actins are also pulled inwards thereby causing shortening of the sarcomere.,ie.,Contraction occurs.