The structures found on either side of the synapse vary depending on the type of synapse:Ī connection formed between the axon of one neuron and the dendrite of another. The synapse itself is the site of transmission from the pre-synaptic neuron to the post-synaptic neuron. The microtubules will help to transport the neurotransmitters from the cell body down to the pre-synaptic terminal, where they will be released. It is a cylindrical tube that is covered by the axolemma and is supported by neurofilaments and microtubules. Generally, the outflow tract of the neuron. They receive incoming signals from other neurons and relay them to the cell body, where the signals are integrated, and a response will be initiated. These are small projections from the cell body that serves a receptive role in the physiology of the neuron. Most of the neurotransmitters that will eventually be released at the synapse are synthesized here. The cell body contains the nucleus and is the site of metabolic activity. ![]() In the simplest sense, the neuron consists of a cell body, axons, and dendrites. The postsynaptic neuron integrates all the signals it receives to determine what it does next, for example, to fire an action potential of its own or not. The type of neurotransmitter released from the presynaptic terminal and the specific receptors present on the corresponding postsynaptic terminal is critical in determining the quality and intensity of information transmitted by neurons. The neurotransmitter rapidly (in microseconds) diffuses across the synaptic cleft and binds to specific receptors. The postsynaptic terminal membrane is less than 50 nanometers away and contains specialized receptors. The presynaptic terminal is at the end of an axon and is the place where the electrical signal (the action potential) is converted into a chemical signal (neurotransmitter release). A synapse is made up of a presynaptic and postsynaptic terminal. Each neuron has anywhere between a few to hundreds of thousands of synaptic connections, and these connections can be with itself, neighboring neurons, or neurons in other regions of the brain. The places where neurons connect and communicate with each other are called synapses. ![]() All rights reserved.The human brain is made up of approximately 86 billion neurons that “talk” to each other using a combination of electrical and chemical (electrochemical) signals. We review here our current understanding of the mechanisms that govern the biogenesis, transport, and assembly of the key components for presynaptic neurotransmission, discuss how alterations in presynaptic assembly may impact nervous system function or lead to disease, and outline key open questions for future research.Ĭopyright © 2020 Elsevier Inc. ![]() In contrast with the significant progress that has been made in understanding synaptic transmission and processing of information at the post-synapse, comparably little is known about the formation and dynamic remodeling of the presynaptic compartment. As the biosynthetic machinery is largely restricted to the somatodendritic domain, the vast majority of presynaptic components are synthesized in the neuronal soma, packaged into synaptic precursor vesicles, and actively transported along the axon to sites of presynaptic biogenesis. Neurons are highly polarized cells with a single axon and multiple dendrites derived from the cell body to form tightly associated pre- and postsynaptic compartments.
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