Neurons and synaptic transmission

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  • Created by: EloiseMay
  • Created on: 20-03-18 16:57

100 billion neurons in the nervous system - 80% are in the brain.

Types of neurons: Motor neurons connect the CNS to effectors (short dendrites, long axons), relay neurons connect sensory neurons to motor neurons and other relay neurons (short dendrites, short axons), and sensory neurons carries messages from the PNS to the CNS (long dendrites, short axons).

The structure of a neuron: The cell body contains the nucleus which contains genetic information for that cell. Dendrites protrude through the cell body and carry impulses from nearby neurons to the cell body. The axon carries impulses away from the cell body. These are covered in a fatty layer called myelin sheath which protect the axon and speed up electrical transmission of the impulse. Myelin sheath is segmented into gaps called nodes of Ranvier which speed up transmission by forcing the impulse across the gaps along the axon. At the end of an axon is the terminal button which communicate to the next neuron across the synapse.

Electrical transmission

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