Neurones

Neurones

1. Structure

   • cell body
     • contains nucleus
     • lots of rough endoplasmic reticulum
       • produces proteins and neurotransmitters
   • dendrons
     • dendrites
       • carries nerve impulses TO cell body
   • axon
     • single long fibre
       • carries nerve impulses AWAY from cell body
     • surrounded by
       • Schwann cells
         • protection and electrical insulation
         • carry out phagocytosis
           • removal of cell debris
         • involved in nerve regeneration
         • nodes of Ranvier
           • gaps between Schwann cells where there's no myelin sheath
       • wrapped around many times
     • myelin sheath
       • made of membranes of Schwann cells
         • rich in myelin

2. Types

   • Myelin sheath
     • unmyelinated neurones
     • myelinated neurones
       • transmit nerve impulses faster
   • Classifications
     • sensory
       • receptor
         • to intermediate or motor neurone
       • one dendron
         • carries to cell body
       • one axon
         • carries away from cell body
     • motor
       • intermediate or sensory
         • to effector
           • glands
           • muscles
       • long axon
       • many short dendrites
     • intermediate
       • transmit between neurones

3. Specialised cells adapted to carry nerve impulses across the body.