You do not have single neurotransmitter, which is released from axon terminals. There are many. Some facilitate the conduction of the impulse and others inhibit the same. You have acetylcholine, norepinephrine, dopamine and many others acting as neurotransmitter.
The neurotransmitter released at the axon bulb is acetylcholine.
Norepinephrine is mainly secreted by the adrenal medulla and also by specific neuron terminals in the sympathetic nervous system. It acts as both a hormone (when released into the bloodstream) and a neurotransmitter (when released at synapses).
Synaptic vesicles store neurotransmitters to be released into the synapses. In the case of most motoneurons, this neurotransmitter is acetylcholine (ACh). The neurons that interface with the sympathetic nervous system, also technically motoneurons, release norepinephrine.
The ion that enters the axon nerve terminal to trigger neurotransmitter release is calcium (Ca2+). When an action potential reaches the nerve terminal, voltage-gated calcium channels open, allowing calcium ions to flow into the cell and initiate the process of exocytosis of neurotransmitter-containing vesicles.
Synapses are located throughout the nervous system. A synapse is a sort of 'relay station' where a message, in the form a a chemical neurotransmitter, is passed on between one neuron (nerve fibre) & the next, or between a neuron & the muscle or gland the message is aimed at.
The substance that is released at an axonal ending to propagate the nerve impulse to the next nerve or muscle is called
The neurotransmitter is released from the axon terminal.
The neurotransmitter released at the axon bulb is acetylcholine.
Synaptic delay is the period of time for neurotransmitter chemicals released from the axon terminus of the sending neuron to cross the synaptic gap by diffusion and attach to matching receptors on the receiving neuron, initiating a reaction (either stimulatory or inhibitory) in that neuron.
The chemical released by the axon that travels across a synapse and binds to dendrites or cells is called a neurotransmitter. Neurotransmitters play a crucial role in transmitting signals between neurons and regulating various physiological processes in the body.
nerve impulse
Synaptic vesicle
When an action potential reaches the axon terminal, it triggers the opening of voltage-gated calcium channels. Calcium ions enter the axon terminal, leading to the fusion of neurotransmitter-containing vesicles with the synaptic membrane. The neurotransmitter is then released into the synaptic cleft where it can bind to receptors on the postsynaptic neuron.
Signals are transmitted along the axon at the axon terminals or synaptic boutons. These structures are located at the ends of axon branches and contain neurotransmitter-filled vesicles that are released into the synapse to communicate with neighboring cells.
neurotransmitter
The neurotransmitter acetylcholine is released from neuron axon terminals and binds to nicotinic receptors on muscle cells, triggering muscle contraction.
Most neurons have a chemical synapse, which is to say that a substance called a neurotransmitter is released from the first neuron (called pre-synaptic) to the next neuron called (post-synaptic). How is the release triggered? When an action potential reaches the terminus (end of the axon) there are specialized calcium channels that are opened (voltage-gated). The calcium bind so the inner membrane and triggers the release of small membrane bound vesicles which spill out their contents of neurotransmitter into the synaptic cleft. The neurotransmitter binds to specific receptors on the post-synaptic membrane and that causes the action potential to propagate on (or for the neurotransmitter to cause an action like a muscle contraction).