Last update:

Neuron – Basic Structure and Functions

  • Neurons (nerve cells) are the functional units of the nervous system. Even though they vary in size and shape, most have structural characteristics similar to the spinal cord neuron shown to left. Neurons have at their core an expanded area of cytoplasm called the image descriptioncell body (soma or perikaryon).
An image showing the Cell body of neuron which is labeled with standard structures from spinal cord segment
1
2
  • It surrounds the nucleus and contains the organelles that perform many of the cell’s supportive metabolic functions.
  • A single, branched image descriptionaxon extends from one side of the cell body.
An image showing the Cell body of neuron which is labeled with standard structures from spinal cord segment
An image showing the Axon and Cell body of neuron with standard structures all labeled ,from spinal cord segment
1
2
  • This elongated cytoplasmic process transports action potentials (electro-chemical impulses) away from the cell body (conduction) and releases neurotransmitter from its bulbous ends (secretion).
  • Also attached to the cell body are several branched image descriptiondendrites.
An image showing the Axon and Cell body of neuron with standard structures all labeled ,from spinal cord segment
An image showing the Dendrites, Axon and Cell body of neuron with standard structures all labeled ,from spinal cord segment
1
2
  • The dendritic processes form part of the receptive zone of the neuron, and changes in the environment causes them to send weak electochemical signals toward the cell body and axon (excitability or irritability).
  • Many neurons do not have the same structural characteristics just described.
  • Instead, they may have: a. dendrites and an axon that do not directly attached to the cell body. b. dendrites that attach directly to the axon. c. only one dendrite.
  • In summary, neurons are enlogated cells that display the physiological properties of excitability (irritability), conduction, and secretion.
  • Due to their functional and cellular specialization, most neurons have lost the ability to mitotically divide, They, therefore, must last a lifetime.

Overview:

Test yourself image showing the Dendrites, Axon and Cell body of neuron with standard structures without answers,from spinal cord segment
Test yourself image showing the Dendrites, Axon and Cell body of neuron with standard structures with answers below,from spinal cord segment
Swipe to show/hide the answers
1
2