This is an unofficial archive of PsychonautWiki as of 2025-08-11T15:14:44Z. Content on this page may be outdated, incomplete, or inaccurate. Please refer to the original page for the most up-to-date information.
Neuron: Difference between revisions
>Oskykins No edit summary |
>Oskykins |
||
| Line 2: | Line 2: | ||
==Structure== | ==Structure== | ||
[[File:MRuueFj.png| | [[File:MRuueFj.png|300px|thumb|right|Structure of the neurone (click to expand)]] | ||
A typical neurone possesses a cell body (often called the soma), dendrites, and an axon. Dendrites are thin structures that arise from the cell body, often extending for hundreds of micrometres and branching multiple times, giving rise to a complex "dendritic tree." An axon is a special cellular extension that arises from the cell body at a site called the axon hillock and travels for a distance. At the majority of synapses, signals are sent from the axon of one neurone to a dendrite of another. There are, however, many exceptions to these rules. For example, neurones that lack dendrites, neurones that have no axon, and synapses that connect an axon to another axon or a dendrite to another dendrite, etc. | A typical neurone possesses a cell body (often called the soma), dendrites, and an axon. Dendrites are thin structures that arise from the cell body, often extending for hundreds of micrometres and branching multiple times, giving rise to a complex "dendritic tree." An axon is a special cellular extension that arises from the cell body at a site called the axon hillock and travels for a distance. At the majority of synapses, signals are sent from the axon of one neurone to a dendrite of another. There are, however, many exceptions to these rules. For example, neurones that lack dendrites, neurones that have no axon, and synapses that connect an axon to another axon or a dendrite to another dendrite, etc. | ||
[[File:Axon.png|428px|thumb|right|Structure of axon membrane]] | [[File:Axon.png|428px|thumb|right|Structure of axon membrane]] | ||
==Propagation of action potentials== | ==Propagation of action potentials== | ||
All neurones are electrically excitable, maintaining voltage gradients across their membranes by means of metabolically driven ion pumps, which combine with ion channels embedded in the membrane to generate intracellular-versus-extracellular concentration differences of ions such as sodium, potassium, chloride, and calcium. Changes in the cross-membrane voltage can alter the function of voltage-dependent ion channels. If the voltage changes by a large enough amount, an "all-or-nothing" electrochemical pulse called an action potential is generated, which travels rapidly along the cell's axon, and activates synaptic connections with other cells when it arrives. | All neurones are electrically excitable, maintaining voltage gradients across their membranes by means of metabolically driven ion pumps, which combine with ion channels embedded in the membrane to generate intracellular-versus-extracellular concentration differences of ions such as sodium, potassium, chloride, and calcium. Changes in the cross-membrane voltage can alter the function of voltage-dependent ion channels. If the voltage changes by a large enough amount, an "all-or-nothing" electrochemical pulse called an action potential is generated, which travels rapidly along the cell's axon, and activates synaptic connections with other cells when it arrives. | ||