Neurons and Synaptic Transmission Flashcards
What are the 3 types of neurons?
- Sensory
- Relay
- Motor
What is the role of the axon?
Carries the impulse from the cell body down the length of the neuron
What is the action potential?
When inside of neurone becomes positvely charged for a short time- this creates the electrical impulse that travels through the axon to the end of the neurone.
What is the axon terminal?
The end of the axon where synaptic vesicles are held
Explain the process of synaptic transmission.
- The electric signal, called the action potential moves from the axon to the axon terminal of the pre-synaptic neuron.
- At the axon terminal, the vesicles, full of neurotransmitters, are stimulated to move to the end of axon terminal, where they fuse with the cell membrane.
- This enables the neurotransmitters to be released into the synapse (synaptic cleft), a small gap between the pre and post synaptic neuron.
- Some of the neurotransmitters reach the correct receptors on the dendrites of the post synaptic neuron.
- (Could add in a point about the NTS are excitatory they cause an action potential in the post synaptic neuron) The neurotransmitters left in the synapse are reabsorbed/ uptaken back into the presynaptic neuron.
Where are neurons located?
Motor Neurones
- Cell bodies of motor neurones may be in the CNS
- But they have long axons that form part of the PNS
Sensory Neurones:
- Located outside of the CNS in the PNS in clusters known as ganglia
Relay neurones
- Make up 97% of all neurones & most are found within the brain & visual system
How does electrical transmission occur? (The firing of a neuron)
- When a neurone is at a resting state the inside of the cell is negatively charged compared to the outside
- When a neurone is activiated by a stimulus the inside of the cell becomes positvely charged for a split second causing an action potential to occur
- This creates an electrical impulse that travels down the axon towards the end of the neurone
