Neurones

Within the peripheral nervous system, neurones are the fundamental unit of nervous tissue. Typically, there are dendrites converging on a cell body; the cell body forms a single nerve fibre - an axon - that relays signals to the end sensory, motor or autonomic organ. The axon contains many neurofibrils. Neurones are subdivided into:

• motor neurones:
  • large cell body in ventral horn of spinal cord
  • multiple dendrites attached to cell body
  • long axon to target organ leaving the spinal cord via the ventral roo
  • axon terminates on the motor end plate of the innervated muscle
• sensory neurones:
  • cell body in the dorsal root ganglion
  • single axon running from sensory organ which may be a sensory organ such as a Meissner's corpuscle, or a free ending within the skin
  • axon passes through dorsal root ganglion
  • axon synapses within the spinal cord either:
    • within the dorsal horn
    • ascending to the brainstem
• sympathetic neurones:
  • unmyelinated
  • control vasomotor and pilomotor function