Sensory and motor neurones

Definition

Transmit an action potential around the body

• sensory neurones - carry action potentials from sensory receptors to central nervous system
• motor neurones - carry action potential from central nervous system to an effector e.g. muscle/gland
• relay - connect sensory  and motor neurones

• Very long - can transmit action potentials over long distances
• Cell surface membrane has many gated ion channels - control entry / exit of Sodium, Potassium and Calcium ions
• Sodium potassium pumps - use ATP to actively transport Sodium ions out of cell and Potassium ions in
• Maintain a potential difference across cell surface membranes - 
• Surrounded by myelin sheath - insulates the neurone from electrical activity in nearby cells
• Cell body contains nucleus, many mitochondria and ribosomes - mitochondria enable active transport to be carried out
• Motor neurones have their cell body in the CNS and have a long axon - this carries the action potential out to the effector
• Sensory neurones have a long dendron - carries action potential to cell body just outside the CNS. Short axon - carries action potential into CNS
• Numerous dendrites in both - to connect to other neurones.