PHYSIOLOGY
SYNAPTIC PHYSIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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the presynaptic terminal is separated from the postsynaptic terminal by the synaptic cleft.
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the presynaptic terminal contains vesicles filled with sodium ions.
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the presynaptic terminal contains receptor molecules for the neurotransmitter.
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the neurotransmitter causes an action potential in the presynaptic terminal.
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All of these conditions occur.
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Detailed explanation-1: -The presynaptic nerve terminal is separated from the postsynaptic muscle fiber by about a 50-nm-wide synaptic cleft, and the junction is insulated by a thin layer of Schwann cells. The terminal contains mitochondria and a large number of synaptic vesicles, which contain the transmitter acetylcholine.
Detailed explanation-2: -In case of neuromuscular junction, the presynaptic terminal is an axonal terminal of a motor neuron. The axonal terminal contains a number of synaptic vesicles. These vesicles contain the neurotransmitters that are released upon receiving a nerve impulse. The presynaptic terminal also has calcium channels.
Detailed explanation-3: -For convenience and understanding, the structure of NMJ can be divided into three main parts: a presynaptic part (nerve terminal), the postsynaptic part (motor endplate), and an area between the nerve terminal and motor endplate (synaptic cleft).
Detailed explanation-4: -First, there is a distinct separation between the presynaptic and the postsynaptic membrane. The space between the two is known as the synaptic cleft.
Detailed explanation-5: -The synaptic cleft is the small space separating the presynaptic membrane and postsynaptic membrane (usually the dendritic spine). Neurotransmitters are chemicals that are released by neurons and bind to receptor sites of membrane proteins.