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An electrical synapse is an electrically conductive link between two abutting neurons that is formed at a narrow gap between the pre- and postsynaptic cells, known as a gap junction. At gap junctions, cells approach within about 3.5 nm of each other, rather than the 20 to 40 nm distance that separates cells at chemical synapses.
Each gap junction (sometimes called a nexus) contains numerous gap junction channels that cross the plasma membranes of both cells. [11] With a lumen diameter of about 1.2 to 2.0 nm, [2] [12] the pore of a gap junction channel is wide enough to allow ions and even medium-size molecules like signaling molecules to flow from one cell to the next, [2] [13] thereby connecting the two cells' cytoplasm.
Chemical and electrical synapses are two ways of synaptic transmission. In a chemical synapse, electrical activity in the presynaptic neuron is converted (via the activation of voltage-gated calcium channels) into the release of a chemical called a neurotransmitter that binds to receptors located in the plasma membrane of the postsynaptic 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 ...
The formation of the new membrane is a protein mediated process and can only occur under certain conditions. After an action potential, Ca 2+ floods to the presynaptic membrane. Ca 2+ binds to specific proteins in the cytoplasm, one of which is synaptotagmin, which in turn trigger the complete fusion of the synaptic vesicle with the cellular ...
Neurons communicate with other cells via synapses, which are specialized connections that commonly use minute amounts of chemical neurotransmitters to pass the electric signal from the presynaptic neuron to the target cell through the synaptic gap. Neurons are the main components of nervous tissue in all animals except sponges and placozoans.
Neurons are diverse with respect to morphology and function. Thus, not all neurons correspond to the stereotypical motor neuron with dendrites and myelinated axons that conduct action potentials. Some neurons such as photoreceptor cells, for example, do not have myelinated axons that conduct action potentials. Other unipolar neurons found in ...
Two connexons, joined across a cell membrane, comprise a gap junction channel. When two identical connexons come together to form a gap junction channel, it is called a homotypic channel. When one homomeric connexon and one heteromeric connexon come together, it is called a heterotypic gap junction channel. When two heteromeric connexons join ...