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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.
Describe how synapses work?
The action potential reaches the pre synaptic area, which opens a voltage sensitive Calcium ion gate, allowing calcium ions to move in via diffusion along an electrochemical gradient. The period of refraction (repolarisation) closes this gate. The increased conc. of Calcium ions pushes vesicles with neurotransmitter to the presynaptic membrane, where they fuse and exocytosis causes the neurotransmitter to be released across the synaptic cleft. The NT binds to a receptor which opens Na+ channels on the postsynaptic membrane, allowing depolarisation due to Na+ diffusion which continues the action potential across the other neurone. The neurotransmitters are broken down by enzymes or are reabsorbed by endocytosis into the presynaptic cleft, using energy from ATP.
Receptors for acetylcholine are located on the?
Acetylcholine receptors are located on the motor end plate or postsynaptic sarcolemma. Otto Loewi was a German pharmacologist whose discovery of acetylcholine earned the 1936 Nobel prize in Physiology or Medicine which he shared with Sir Henry Dale. Acetylcholine is a neurotransmitter. Neurotransmitters are chemicals that transmit signals from a neuron to a target cell across the synapse and most are synthesized at the nerve terminals.
Into what does the neuron release its neurotransmitter at the neuromuscular junction?
The neuron releases its neurotransmitter into the synaptic cleft at the neuromuscular junction, which is the gap between the neuron terminal and the muscle cell. This neurotransmitter then binds to receptors on the muscle cell membrane, triggering muscle contraction.
Binding of neurotransmitter to the receptors on the motor endplate open?
When a neurotransmitter binds to its receptor on the motor endplate, it triggers the opening of ion channels in the postsynaptic membrane. This allows for the influx of ions, typically leading to depolarization of the muscle cell membrane and initiation of a muscle action potential. Subsequently, this leads to contraction of the muscle fiber.
Compound that influences a postsynaptic cell's response to a neurotransmitter?
neuromodulator
What is the difference between presynaptic and postsynaptic neurons?
Presynaptic neurons release the neurotransmitter in response to an action potential. Postsynaptic neurons receive the neurotransmitter (and can however become presynaptic to the next nerve cell, if the neurotransmitter has stimulated the cell enough).
What a neurotransmitter is?
A neurotransmitter is a chemical or peptide in synapses, usually between neurons, a neuron and muscle or a neuron and other organ. The neurotransmitter transmits information to and from and within the brain. When a neurotransmitter is released from the presynaptic cell in response to depolarization of the cell by an action potential, it diffuses across the synaptic cleft and binds a receptor or ligand-gated ion channel on the postsynaptic cell. Binding on the postsynaptic cell alters the resting potential of the postsynaptic cell in either an inhibitory or excitatory manner, making the cell less susceptible or more susceptible (respectively) to an action potential. Examples include, but are not limited to, acetylcholine, GABA, noradrenaline, serotonin and dopamine.
Are neurotransmitter expelled from the presynaptic cells?
Yes, neurotransmitters are released from the presynaptic cells into the synaptic cleft where they can bind to receptors on the postsynaptic cell. This release occurs in response to an action potential traveling down the axon of the presynaptic neuron.
A chemical found in the synaptic vesicles that when released has an effect on the next cell is called a?
neurotransmitters
What sequence of events occurs when an action potential arrives at the presynaptic terminal?
When an action potential arrives at the presynaptic terminal, voltage-gated calcium channels open, allowing calcium ions to enter the cell. The influx of calcium triggers the release of neurotransmitter vesicles from the presynaptic terminal into the synaptic cleft. These neurotransmitters then bind to receptors on the postsynaptic membrane, leading to changes in the postsynaptic cell's membrane potential.
What is a synapse?
There are several types of synapses in the body. The most commonly discussed type is the chemical synapse, but other types of synapses include electrical synapses and immunological synapses. Because chemical synapses are the most commonly discussed synapses in general, that's probably what this question is referring to.A chemical synapse is a small gap, or commonly referred to as a connection, between two cells that allows for the first cell (the presynaptic cell) to communicate with the second cell (the postsynaptic cell) through a chemical signal. These chemical signals are called neurotransmitters, and once they are released by the presynaptic cell, they act on the postsynaptic cell through specialized protein molecules called neurotransmitter receptors.The actions triggered by a neurotransmitter binding its receptor on the postsynaptic cell are highly varied. They vary according to the type, quantity, and frequency of neurotransmitter release, the specific receptor involved, the type of cell that is receiving the neurotransmitter signal, among other things. For example, a neurotransmitter called glutamate typically causes activation of the postsynaptic cell, while a neurotransmitter called GABA typically inhibits postsynaptic cells. Likewise, if the postsynaptic cell belongs to a gland, then activity in that cell may promote secretion, while inhibition may hinder secretion. If the postsynaptic cell is a muscle fiber, then activation triggers muscle contraction, while inhibition causes relaxation.A synapse is a connection which allows for the transmission of nerve impulses. Synapses can be found at the points where nerve cells meet other nerve cells, and where nerve cells interface with glandular and muscular cells. In all cases, this connection allows for the one-way movement of data. The human body contains trillions of synapses, and at any given time, huge numbers of these connections are active.
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.
What is meant by summation at a synapse and how can the two ways it is accomplished be described?
Summation is the method in which signal transmission between neurons occurs. Summation occurs through excitatory neurotramitters and inhibitory neurotransmitters. Excitatory produces depolarization of the postsynaptic cell. Inhibitory mitigates the effects of an excutatory neurotransmitter. For more information visit the Related Link.
Chemicals found in the synaptic vesicles which when released has an effect on the next cell?
a neurotransmitter
How do signal molecules change how a cell will function?
Signal molecules act as a neurotransmitter or a hormone, which both effect how a cell functions.
What is The purpose of axon?
As far as I understand it, the purpose of the axon is to transmit the electrical impulses (information) of the presynaptic dendrites away from the cell body. The axon therefore acts as a sort of barrier between the postsynaptic dendrites, as it is kind of a one-way street from the cell body to the postsynaptic dendrites. As for why this is necessary, I have no clue. I would assume that if electrical information were to get caught up and stuck somewhere in the cell that it might be damaging to the neuron itself. The purpose of the axon would ultimately be to get the electrical information from the cell body to the postsynaptic dendrites so that chemical production on the neurotransmitter takes place.
