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Dendrites – Structure and Functions

  • image descriptionDendrites are often, but not always, branched cytoplasmic processes that attach to one side of the cell body.
An image of a neuron showing the dendrites in separated illustration (expand)
An image of a neuron showing the dendrites (which is labeled) in separated illustration (expand)
  • 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 image descriptionneurotransmitter molecules released by the axons of nearby neurons.
  • 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 image descriptionion diffuse through the receptor channels.
  • The ion exchange image descriptionalters 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.