Neurons and Synaptic Transmissions Flashcards
What are the three types of neurons?
Motor
Relay
Sensory
What is the role of the sensory neuron?
To carry messages from the PNS to the CNS. They have long dendrites and short axons
What is the role of the motor neuron?
To connect the CNS to effectors such as muscles and glands. They have short dendrites and long axons
What is the role of the relay neuron?
To connect the sensory neurons to the motor neurons or other relay neurons. They have short dendrites and short axons.
What is synaptic transmission?
The process by which a nerve impulse passes across the synaptic cleft from the presynaptic neuron to the postsynaptic neuron
What is excitation?
When a neurotransmitter increases the positive charge of the postsynaptic neuron, increasing the likelihood that the neuron will fire. E.g. adrenaline
What is inhibition?
When a neurotransmitter makes the charge of the postsynaptic neuron more negative, decreasing the likelihood that the neuron will fire. E.g. Serotonin
What is summation?
The net result of adding up the excitatory and inhibitory neurotransmitters binding to the receptors- determines whether or not the neuron fires
What is the function of a Dendrite?
Carry nerve impulses from neighbouring neurons towards the cell body
What is the function of a Nucleus?
Contains the genetic material of the cell
What is the function of a Cell body/soma?
Carries the nucleus
What is the function of a Axon?
Carries the nerve impulses away from the cell body
What is the function of a Myelin Sheath?
A fatty layer around the axon which protects the axon and speeds up electrical transmission of the impulse. (This would have the opposite effect without the nodes of Ranvier).
What is the function of a Nodes of Ranvier?
Gaps in the myelin sheath which speed up transmission of impulse by forcing it to ‘jump’ across the gaps in the axon.
What is the function of a Terminal buttons?
At the end of the axon that communicate with the next neuron in the chain across the synapse
