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True or False A neurotransmitter substance crosses the synaptic cleft between a nerve and muscle fiber and stimulates the nerve to have an action potential?
Wiki User
∙ 13y ago
False
Wiki User
∙ 13y ago
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What are the principles of synaptic transmission?
Calcium ions enter the presynaptic neuron resulting in the release of neurotransmitter from the per-synaptic membrane. The neurotransmitter diffuses across the synaptic cleft, fusing with the receptors of the post-synaptic membrane. This changes the sodium channels to open and sodium ions will to flow into the post-synaptic neuron, depolarizing the post-synaptic membrane. This initiates an action potential. After the post-synaptic neuron has been affected, the neurotransmitter is removed by a type of enzyme called cholinesterase. The inactivated neurotransmitter then returns to the pre-synaptic neuron.
What crosses the synaptic cleft and stimulates the muscle fiber to contract?
Short answer: Neurotransmitters Long answer: amino acids, monoamines, peptides
How do nerves impulse's across the synapse?
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).
What are the criteria for a substance in a neurotransmitter at a synapse?
Criteria required identifying a substance as a neurotransmitter 1- ) Synthesis of the substance: • It is synthesized in the neuron • Some substances are synthesized from the Tryptophan • Rate limiting step in its synthesis • Enzymes required in the synthesis of that substance are themselves synthesized in the cell body of neuron ,then distributed throughout the neuron • Mainly found in the cell body and nerve terminal • These enzymes are stored in the presynaptic terminal of neuron, inside the synaptic vesicles. 2- ) Storage of that substance: • The neutransmitter is stored inside the synaptic vesicle of nerve terminal 3- ) Release of the neurotransmitter: • It is released from the nerve terminal usually through Ca++ dependent process following the stimulation of the nerve fiber by action potential. • Fusion of the synaptic vesicle with the nerve membrane releasing neurotransmitter outside the nerve fiber into the synaptic cleft. 4- ) Exogenous analogue (drug) of the neurotransmitter: • If drug analogue of the neurotransmitter is injected exogenously, it should mimic the same mechanism of action as done by the endogenously released neurotransmitter.
Is it the synaptic cleft that contains vesicles filled with acetylcholine?
The synaptic knob contains vesicles filled with neurotransmitters. Therefore, Acetylcholine is the neurotransmitter that stimulates skeletal muscle to contract. It is released into the synaptic clefts between motor neuron axons and motor end plates.
Is it true that a post synaptic potential is a graded potential that is the result of a neurotransmitter released into the synapse between two neurons?
because i dnt know hahaha
When an action potential passes over the surface of synaptic knob the contents of vesicles is released in the presence of?
exocitocisThey dir
How do nerve impulses travel across the synapse?
By a chemical released by an axon.
What is synaptic potential?
synaptic potential
What happens after nerve signal reaches a synaptic knob?
In general, action potentials that reach the synaptic knobs cause a neurotransmitter to be released into the synaptic cleft. The arrival of the action potential opens voltage-sensitive calcium channels in the presynaptic membrane.
What type of ion channel opens on the synaptic end bulb in response to depolarisation?
Calcium (Ca2+) channels open on the synaptic end bulb in response to depolarization (from the action potential), inducing exocytosis of synaptosomes containing neurotransmitter, resulting in neurotransmitter being released into the synaptic cleft...further propagating the signal to the next neuron or set of neurons.
What ion triggers the release of a neurotransmitter at the presynaptic membrane?
Calcium triggers synaptic vesicles to discharge the neurotransmitter into the synaptic cleft.
