Question

q4.4. which statement below is true about neurotransmitters? the entry of neurotransmitter through k+ channels into neurons triggers the rising phase of the action potential. neurotransmitters are released from muscle cells to activate motor neurons in the presence of botulinum toxin. neurotransmitters are released from a neuron when the action potential reaches the end of its axon. all of the above.

Explanation:

1. The rising phase of the action potential is triggered by the influx of $Na^+$ ions, not neurotransmitters through $K^+$ channels.
2. Botulinum toxin inhibits the release of neurotransmitters from motor - neurons to muscle cells, not the other way around.
3. When an action potential reaches the end of a neuron's axon, neurotransmitters are released from synaptic vesicles into the synaptic cleft.

Answer:

The statement "Neurotransmitters are released from a neuron when the action potential reaches the end of its axon" is True.