Neurons and Synaptic Transmission

Question 1

explain the process of synaptic transmission

Answer 1

• Electrical impulse is sent down presynaptic neuron to the terminal button and reaches the vesicles
• It stimulates the release of neurotransmitters from the vesicles
• These bind to the receptors depending on their shape, like a lock and key
• receptors are then stimulated
• the electrical impulse is then reformed in the post-synaptic neuron
• All neurotransmitters transmitters of re-uptaken by the re-uptaker
• An action potential travels down the Axon, to the presynaptic terminal button and stimulates release of neurotransmitters, into small vesicle sacs
• Vesicles release neurotransmitter into Synaptic cleft
• Neurotransmitters binds to receptors and activates them
• Excess neurotransmitter is taken up by the pre-synaptic neuron by a reuptaker
• Enzymes are released to breakdown the remaining neurotransmitters in the synaptic fluid
• Vesicles are replenished with new and reused neuro transmitters.
• The neurotransmitters on the post- Synaptics neurone all converted back into an electrical impulse

Question 2

outline how excitation and inhibition are involved in synaptic transmission

Answer 2

Neurotransmitters can be excitatory or inhibitory
Excitatory - increase the charge of the postsynaptic neuron e.g. Adrenaline
Inhibitory - decrease the charge of the postsynaptic neuron e.g. Serotonin

Neurotransmitters bind to receptors and an action potential reforms based on pre-synaptic inputs
more excitatory, more positive, more likely to continue an action potential
more inhibitory, more negative, less likely to continue an action potential

All this occurs after synaptic transmission takes place