What happens during muscle depolarization?

Activation of the nAChR leads to an influx of cations (sodium and calcium) that causes depolarization of the muscle cell membrane. This depolarization in turn activates a high density of voltage-gated sodium channels on the muscle membrane, eliciting an action potential.

What is depolarization of muscle fibers?

Once ACh binds, a channel in the ACh receptor opens and positively charged ions can pass through into the muscle fiber, causing it to depolarize, meaning that the membrane potential of the muscle fiber becomes less negative (closer to zero.)

What is the difference between contraction and relaxation of muscles?

Answer: Muscle contraction is the activation of tension-generating sites within muscle fibers. The termination of muscle contraction is followed by muscle relaxation, which is a return of the muscle fibers to their low tension-generating state.

How muscles contract and relax?

When the stimulation of the motor neuron providing the impulse to the muscle fibers stops, the chemical reaction that causes the rearrangement of the muscle fibers’ proteins is stopped. This reverses the chemical processes in the muscle fibers and the muscle relaxes.

What causes cell depolarization?

Depolarization is caused when positively charged sodium ions rush into a neuron with the opening of voltage-gated sodium channels. Repolarization is caused by the closing of sodium ion channels and the opening of potassium ion channels.

What causes depolarization of a cardiac muscle cell to occur?

In nerve and muscle cells, the depolarization phase of the action potential is caused by an opening of fast sodium channels. This also occurs in non-pacemaker cardiac cells; however, in cardiac pacemaker cells, calcium ions are involved in the initial depolarization phase of the action potential.

What is cardiac depolarization?

What is meant by depolarization of the heart? Depolarization of the heart is the orderly passage of electrical current sequentially through the heart muscle, changing it, cell by cell, from the resting polarized state to the depolarized state until the entire heart is depolarized.

When a cell Depolarizes what happens to the membrane potential?

movement of a cell’s membrane potential to a more positive value (i.e. movement closer to zero from resting membrane potential). When a neuron is depolarized, it is more likely to fire an action potential.