Neurons

• The nervous system is composed of nerve cells called neurons 
• The nervous system communicates information all around the body by sending signals across these neurons 
• The signals travel around the body, to other neurons, muscles or glands extremely quickly 
• Neurons send messages electrochemically 
• The nervous system can send signals at a rate of 100 metres per second
• There are three types of neurons in the nervous system 

  • Sensory- sensory neurons are nerve cells that transmit information from a receptor (e.g. cells that detect light, sound, temperature etc) to the CNS
  • Interneurons (relay) - Interneurons are located in the CNS and transmit information from sensory neurons to motor neurons 
  • Motor - motor neurons transmit messages from the CNS to the effectors that are typically muscles or glands 
• Neurons use both electrical and chemical signals to transmit information
• Neurons transmit information along their length through electrical impulses called action potentials
• An action potential is a rapid change in voltage across the neurons membrane, caused by the movement of ions in and out of the cell