Biopsychology(synaptic transmission)

Question 1

What happens when an action potential reaches the terminal -

Answer 1

Once an action potential has arrived at the terminal button at the end of the axon, it needs to be transferred to another neuron or tissue. It must cross a gap between the presynaptic membrane and the postsynaptic membrane this is known as the synapse (synaptic cleft).

Question 2

Axon terminal end

Answer 2

At the end of the axon of the nerve cell are a number of sacs known as synaptic vesicles. These contain the chemical messenger (neurotransmitter) which assist in the impulse. As the action potential reaches the synaptic vesicles, it causes them to release their contents through exocytosis.( neurotransmitters and assist in the impulse)

Question 3

What happens during exocytosis?

Answer 3

The released neurotransmitter diffuses across the gap (synaptic cleft) between the pre- and postsynaptic neuron.

Question 4

Where does the neurotransmitter diffuse to?

Answer 4

Across the gap onto the postsynaptic cell, where it binds to specialized proteins called receptors on the surface of the cell and are activated by a specific neurotransmitter.

Question 5

What happens the neurotransmitter binds to the receptor?

Answer 5

Once activated, the receptor molecule will either release an excitatory or inhibitory neurotransmitter/effect on the postsynaptic membrane.

Question 6

How long does the process of synaptic transmission take?

Answer 6

Only a fraction of a second.

Question 7

When the effects are terminated at most synapses what is the process called?

Answer 7

‘re-uptake’, the neurotransmitter is taken up again by the presynaptic neuron and is stored and is made available for later use. How quickly the presynaptic neuron takes back the neurotransmitter from the synaptic cleft determine how long the effects are.