![]() ![]() Synapses are functional connections between neurons, or between neurons and other types of cells. Structure Diagram of a chemical synaptic connectionįurther information on formation of synapses: Synaptogenesis Without a qualifier, however, "synapse" commonly refers to chemical synapses. Chemical synapses are not the only type of biological synapse: electrical and immunological synapses also exist. The word "synapse" was introduced by Sir Charles Scott Sherrington in 1897. The number of synapses in the human cerebral cortex has separately been estimated at 0.15 quadrillion (150 trillion) Every cubic millimeter of cerebral cortex contains roughly a billion ( short scale, i.e. The adult human brain is estimated to contain from 10 14 to 5 × 10 14 (100–500 trillion) synapses. Finally, the neurotransmitters are cleared from the synapse through one of several potential mechanisms including enzymatic degradation or re-uptake by specific transporters either on the presynaptic cell or on some other neuroglia to terminate the action of the neurotransmitter. These molecules then bind to neurotransmitter receptors on the postsynaptic cell. The neurotransmitters are contained within small sacs called synaptic vesicles, and are released into the synaptic cleft by exocytosis. They allow the nervous system to connect to and control other systems of the body.Īt a chemical synapse, one neuron releases neurotransmitter molecules into a small space (the synaptic cleft) that is adjacent to another neuron. They are crucial to the biological computations that underlie perception and thought. Chemical synapses allow neurons to form circuits within the central nervous system. The neurotransmitter binds to chemical receptor molecules located in the membrane of another neuron, the postsynaptic neuron, on the opposite side of the synaptic cleft.Ĭhemical synapses are biological junctions through which neurons' signals can be sent to each other and to non-neuronal cells such as those in muscles or glands. When the action potential reaches the presynaptic terminal, it provokes the release of a synaptic vesicle, secreting its quanta of neurotransmitter molecules. An electrochemical wave called an action potential travels along the axon of a neuron. Artistic interpretation of the major elements in chemical synaptic transmission. For other uses, see synapse (disambiguation). This article is about chemical synapses of the nervous system. ![]()
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