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The synaptic cleft—also called synaptic gap—is a gap between the pre- and postsynaptic cells that is about 20 nm (0.02 μ) wide. [12] The small volume of the cleft allows neurotransmitter concentration to be raised and lowered rapidly.
Chemical synaptic transmission is the transfer of neurotransmitters or neuropeptides from a presynaptic axon to a postsynaptic dendrite. [3] Unlike an electrical synapse, the chemical synapses are separated by a space called the synaptic cleft, typically measured between 15 and 25 nm. Transmission of an excitatory signal involves several steps ...
By attaching to transmitter-gated ion channels, the neurotransmitter causes an electrical alteration in the postsynaptic cell and rapidly diffuses across the synaptic cleft. Once released, the neurotransmitter is swiftly eliminated, either by being absorbed by the nerve terminal that produced it, taken up by nearby glial cells, or broken down ...
During normal conditions, glutamate concentration can be increased up to 1mM in the synaptic cleft, which is rapidly decreased in the lapse of milliseconds. [15] When the glutamate concentration around the synaptic cleft cannot be decreased or reaches higher levels, the neuron kills itself by a process called apoptosis. [16] [17]
The cell receiving the signal, or target cell, may be another neuron, but could also be a gland or muscle cell. [1] Neurotransmitters are released from synaptic vesicles into the synaptic cleft where they are able to interact with neurotransmitter receptors on the target cell.
A diagram of the proteins found in the active zone. The active zone is present in all chemical synapses examined so far and is present in all animal species. The active zones examined so far have at least two features in common, they all have protein dense material that project from the membrane and tethers synaptic vesicles close to the membrane and they have long filamentous projections ...
Exocytosis (/ ˌ ɛ k s oʊ s aɪ ˈ t oʊ s ɪ s / [1] [2]) is a form of active transport and bulk transport in which a cell transports molecules (e.g., neurotransmitters and proteins) out of the cell (exo-+ cytosis). As an active transport mechanism, exocytosis requires the use of energy to transport material.
All neurotransmitters are released into the synaptic cleft via exocytosis from synaptic vesicles. Two kinds of neurotransmitter vesicles exist: large dense core vesicles and small clear core vesicles. Large dense core vesicles contain neuropeptides and large neurotransmitters that are created in the cell body of the neuron and then transported ...