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What is The process by which the neurotransmitter substance leaves the presynaptic terminal button is called?
Leaves the presynaptic neuron, activates ion channel
What portion of a neuron forms the presynaptic neuronal membrane?
Terminal Button
What sequence of events occurs when an action potential arrives at the presynaptic terminal?
calcium ions to diffuse into the cell.
Describe the structure of a synapse?
The synapse consists of two main parts that allow one neuron to communicate with another: 1) the presynaptic terminal located at the end of an axon; and 2) the postsynaptic terminal located on the dendrite of another neuron. The presynaptic terminal is where neurotransmitters are stored and released from. The postsynaptic terminal is the recipient side of the synapse. Neurotransmitters released from the presynaptic terminal will diffuse across the synaptic cleft and bind to receptors located on the surface of dendritic spines.
The sites where a chemical substance is transmitted from the presynaptic terminal of an axon to the postsynaptic membrane of a muscle fiber are called?
neuromuscular junctions
Voltage regulated channels can be found where?
in the membrane that covers axonsThey are located in the axon hillock, nodes of Ranvier, and presynaptic terminal of the neuron.
What is an autoreceptor?
An autoreceptor is a receptor which is situated in the terminal of a presynaptic nerve cell, sensitive to neurotransmitters released by the neuron in whose membrane the autoreceptor sits.
The botulinus toxin that causes botulism acts by?
Botulinus toxin blocks the release of acetylcholine from the presynaptic terminal. This is a total blockage of neuronal transmission.
Which ion causes neurotransmitters vesicles to fuse with the axons membrane during the conduction of a nerve impulse from one to the next?
Calcium ions cause the neurotransmitter vesicles to fuse with the axon terminal. When an action potential reaches the axon terminal, voltage-gated calcium ion pores are opened, allowing calcium ions into the axon terminal. These ions initiate the release of neurotransmitter vesicles stored on elements of the cytoskeleton located near the presynaptic membrane; they then travel to the presynaptic membrane, where they first dock, and then fuse with the presynaptic membrane, forming an opening or pore through which the neurotransmitters are released into the synaptic cleft.
How does neurotransmitters initiate depolarization?
Let's picture a presynaptic neuron, a synaptic cleft, and a postsynaptic neuron. An action potential reaches the terminal of a presynaptic neurone and triggers an opening of Ca ions enters into the depolarized terminal. This influx of Ca ions causes the presynaptic vesicles to fuse with the presynaptic membrane. This releases the neurotransmitters into the synaptic cleft. The neurotransmitters diffuse through the synaptic cleft and bind to specific postsynaptic membrane receptors. This binding changes the receptors into a ion channel that allows cations like Na to enter into the postsynaptic neuron. As Na enters the postsynaptic membrane, it begins to depolarize and an action potential is generated.
How does a message. travel across the gap. at a synapse?
it is sent through the neurotransmittersAt the synaptic terminal an electrical impulse will trigger the migration of vesicles containing neurotransmitters toward the presynaptic membrane.
What is a presynaptic neuron?
a neuron from the axon terminal of which an electrical impulse is transmitted across a synaptic cleft to the cell body or one or more dendrites of a postsynaptic neuron by the release of a chemical neurotransmitter.
