Neuron's and synaptic transmission

• There are three types of neurons;

  1. Sensory neuron
  2. Relay neuron
  3. Motor neuron
• There are 4 structures to a neuron;

  1. Dendrites
  2. Cell body
  3. Axon
  4. Terminail end bulbs
• Dendrites recieve and process signals from other neurons
• The cell body contains the genetic material of the cell and maintains the neurons structure
• The axon carried impulses away from cell body down

  • Covered in myelin sheath - protects the axon
• The myelin steath protects axon
• The myelin sheath is segmented by node of ranvier which speed up transmission allowing it to jump across the gaps
• The terminal end bulbs release neurotransmitters
• Sensory neurons -> carry messages from receptors in the body to the brain and spinal cord

  • Long dendtries and short axon
• Motor neurons -> carrying electrochemical nerve signals from CNS to muscles and glands of the body

  • Short dendrites and long axon
• Relay neurons -> allow sensory and motor neurons to communicate with one another

  • Short dendrites and long axons
• Each neuron is separated from the next with tiny gaps called synapses.
• Synaptic transmission;

  1. Information is passed down axon of neurone as electrial impulse
  2. Once electrical impulse reaches end of neuron it must cross synaptic gap
  3. At end of neuron there are synaptic vesicles which contain neurotransmitters
  4. When electrical impulse reaches vesicles they release their neurotransmitters
  5. Neurotransmitter carry the message across synaptic gap
  6. Neurotransmitters bind to receptor sites on postsynpatic cell and complete process
• Neurotransmitters have either excitatory or inhibitory effects on the neighbouring neurons
• Inhibitory -> makes a nerve impulse less likely to be triggered e.g GABA
• Excitatory -> make a nerve impulse more likely to be triggered e.g Dopamine