Neurone structure and function

• What are neurones?

  Nerve cells send electrical and chemical signals

  There are 100 billion of them in the human body
• What is this?

  Node of Ranvier

  
• What is this

  Myelin sheath

  
• What is this?

  Axon

  
• What is this?

  Dendrite

  
• What is this?

  Soma

  
• What is this?

  Nucleus

  
• What does the cell body do?

  Nucleus with genetic material
• What does an axon do?

  Carries signals from the cell body down the neurone, covered in myelin sheath
• What does a myelin sheath do?

  Fatty layer acts as insulation and gaps speed up signal
• What is the terminal button?

  End of axon
• Electrical transmission

  Resting state- inside has a negative charge compared to outside

  When it fires- changes to a positive charge which causes an action potential
• What happened at the synapse?

  Neurones communicate using neurotransmitters released from pre-synaptic to post signaptic neuron across the synaptic clef
• What is summation?

  Summation occurs if there are more excitary signals than inhibitory signals

  Makes neurons fire causing an electrical impulse
• What is excitation?

  Excitatory neurotransmitters increase the postsynaptic neurons positive charge and make it more likely to fire
• What is inhibition?

  Inhibitory neurotransmitters increase the postsynaptic neurons negative charge and make it less likely to fire
• What is the reuptake of neurotransmitters?

  Neurotransmitters attach themselves to rhe next neuron at the postsynaptic receptor sites

  Tye chemical message is turned back to an electrical impulse

  Neurotransmitters in synaptic cleft broken down by enzymes, reabsorbed by presynaptic neuron