Axon - Structure and Functions
Dendrites – Structure and Functions
They are often, but not always, branched cytoplasmic processes that attach to one side of the cell body.
- They contain many of organelles found in the cell body, which perform the same metabolic functions.
- Dendrites make up most of the receptive zone of a neuron and can detect specific changes in the surrounding environment (stimuli).
- For example, CNS dendrites have membrane receptors that respond to neurotransmitter molecules released by the axons of nearby neurons.
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- The neurotransmitters serve as a stimulus because they change the environment around the dendrites.
- When the neurotransmitters bind to the dendritic receptor, chemical gates open and surrounding ion diffuse through the receptor channels.
- The ion exchange alters the polarity of the dendritic membrane.
- The inside of the receptive relative zone becomes increasing positive relative to the outside.
- If the charge difference reaches a threshold level, it triggers electrochemical events in the axon process of a neuron.
- Dendrites in other parts of the body are receptive to different types of chemical and mechanical stimuli, such as light, touch, stretch, temperature, etc.
- When detected, these stimuli cause similar electrochemical changes to occur in the responding dendrites.