The Structure and Function of Neurons and Synaptic Transmission Flashcards
What are the three types of neuron?
Sensory, Relay and Motor.
What are sensory neurons?
They carry messages from the PNS to the CNS. They have long dendrites and short axons.
What are relay neurons?
These connect the sensory neurons to the motor or other relay neurons. They have short dendrites and short axons.
What are motor neurons?
These connect the CNS to effectors such as muscles and glands. They have short dendrites and long axons.
What are the components of a neuron?
They contain a nucleus in the cell body, with dendrites protruding from it. They carry nerve impulses from neighbouring neurons towards the nucleus. The axon carries the impulses away from the cell body. It is covered in a fatty layer of myelin sheath that protects the axon and speeds up electrical transmission
What is an excitatory effect?
An excitatory neurotransmitter such as adrenaline increases the positive charge of the post-synaptic neuron, making it more likely to fire.
What is an inhibitory effect?
An inhibitory neurotransmitter such as serotonin increases the negative charge of the post-synaptic neuron, making it less likely to fire.
What is summation?
Whether or not a post-synaptic neuron fires or not is as a result of summation - the balance between the negative or positive charge of the neuron. If the net effect is positive then it will fire an electrical impulse, if it is negative then it is less likely to.
