Potassium.
When acetylcholine binds to its receptor in the sarcolemma of a muscle cell, it triggers an action potential to be generated along the muscle cell membrane. This action potential then spreads along the sarcolemma and eventually leads to muscle contraction by initiating the release of calcium ions from the sarcoplasmic reticulum.
Propagation of the action potential along the sarcolemma
The action potential is generated when a stimulus causes a change in the electrical potential across the cell membrane, resulting in the opening of voltage-gated ion channels. This allows an influx of sodium ions, causing depolarization of the membrane and initiation of the action potential.
Acetylcholine binds to its receptors on the sarcolemma, leading to the opening of ion channels that allow sodium ions (Na+) to enter the muscle cell. This influx of sodium ions depolarizes the sarcolemma, generating an action potential. The action potential then travels along the T-tubules, ultimately triggering the release of calcium ions from the sarcoplasmic reticulum, which initiates muscle contraction.
Depolarization of the sarcolemma is the process where there is a change in the electrical charge across the cell membrane of a muscle cell. This change in charge helps to propagate an action potential along the cell membrane, initiating muscle contraction.
An incoming action potential to an alpha motor neuron causes acetylcholine (Ach)release at the end plate, Ach binds to Ach receptors on the sarcolemma causing a sodium influx which causes depolarization.
An action potential is generated at the axon hillock of a neuron, which is the region where the cell body (soma) transitions into the axon. This is where the concentration of voltage-gated sodium channels is highest, allowing for the initiation of the action potential.
Sodium ions are mainly responsible for depolarizing the sarcolemma when acetylcholine receptors open. Sodium influx leads to depolarization of the cell membrane, initiating an action potential.
The T-tubules, or transverse tubules, connect the sarcolemma (muscle cell membrane) to the sarcoplasmic reticulum (membrane network within muscle cells). T-tubules allow for the rapid transmission of action potentials generated at the sarcolemma to the interior of the muscle cell, triggering the release of calcium from the sarcoplasmic reticulum to initiate muscle contraction.
Acetylcholine binding causes nicotinic acetylcholine receptors on the folded sarcolemma to open, allowing the influx of sodium ions into the muscle cell. This initiates an action potential that propagates along the sarcolemma and into the T-tubules, triggering muscle contraction.
it contracts
action potential of the sarcolemma(the membrane)