Search results
Results from the WOW.Com Content Network
Diagram of a chemical synaptic connection. In the nervous system, a synapse [1] is a structure that allows a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or a target effector cell. Synapses can be classified as either chemical or electrical, depending on the mechanism of signal transmission between neurons.
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.
The active zone or synaptic active zone is a term first used by Couteaux and Pecot-Dechavassinein in 1970 to define the site of neurotransmitter release. Two neurons make near contact through structures called synapses allowing them to communicate with each other.
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.
Neurons form complex biological neural networks through which nerve impulses (action potentials) travel. Neurons do not touch each other (except in the case of an electrical synapse through a gap junction); instead, neurons interact at close contact points called synapses. A neuron transports its information by way of an action potential.
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 ...
This bidirectional communication between astrocytes and neurons add complexity to brain signaling, with implications for brain function and neurological disorders. [10] [11] Enzyme degradation – proteins called enzymes break the neurotransmitters down. Reuptake – neurotransmitters are reabsorbed into the pre-synaptic neuron.
The Schaffer collateral is located between the CA3 region and CA1 region in the hippocampus. Schaffer collaterals are the axons of pyramidal cells that connect two neurons (CA3 and CA1) and transfer information from CA3 to CA1. [5] [6] The entorhinal cortex sends the main input to the dentate gyrus (perforant pathway).