Question

The hair cells release neurotransmitters into the synaptic cleft after they’re depolarized by the influx of this ion​:

Ca2+ ​
Cl–
K+​
Na+

Answer 1

Hair cells release neurotransmitters after being depolarized by calcium ions (Ca₂₊) entering through voltage-gated Ca₂₊ channels, leading to exocytosis of neurotransmitter-containing vesicles.

Step-by-step explanation:

Hair cells release neurotransmitters into the synaptic cleft after they’re depolarized by the influx of the calcium ion (Ca₂₊). When an action potential reaches the axon terminal, it depolarizes the membrane and initially opens voltage-gated Na+ channels. Sodium ions enter the cell, further depolarizing the presynaptic membrane which then leads to the opening of voltage-gated Ca₂₊ channels. As Ca₂₊ enters the cell, it initiates a cascade that causes neurotransmitter-containing synaptic vesicles to merge with the presynaptic membrane and release their contents into the synaptic cleft through exocytosis. The neurotransmitter molecules then diffuse across the synaptic cleft and may bind to receptors on the postsynaptic neuron, resulting in localized changes in membrane potential.

Answer 2

When an action potential reaches the axon terminals, voltage-gated Ca2+ channels open and allow Ca2+ to enter the cell. This causes synaptic vesicles to release neurotransmitters into the synaptic cleft, which then bind to ligand-gated ion channels in the postsynaptic membrane.

therefore the correct answer is Ca2+

Step-by-step explanation:

When an action potential reaches the axon terminals, voltage-gated Ca2+ channels open and allow Ca2+ to enter the cell. The calcium entry causes synaptic vesicles to fuse with the membrane and release neurotransmitter molecules into the synaptic cleft. The neurotransmitter diffuses across the synaptic cleft and binds to ligand-gated ion channels in the postsynaptic membrane, resulting in a localized depolarization or hyperpolarization of the postsynaptic neuron.