Biopsychology - Synaptic Transmission

Question 1

What is a synapse?

Answer 1

Each neuron is separated from the next by an extremely tiny gap called the synapse.

Question 2

How do signals travel across the synapse?

Answer 2

Signals with in the neurons are transmitted chemically but signals between neurons are transmitted chemically across the synapse.

Question 3

What is the process of synaptic transmission?

Answer 3

• When the electrical impulse reaches the end of the pre-synaptic terminal it triggers the release of neurotransmitter from tiny sacs called synaptic vesicles allowing the neurotransmitter to diffuse into the synapse.
• Once a neurotransmitter crosses the gap, it is taken up by a post synaptic receptor site on the next neuron, so the impulse only ever travels in one direction.
• The chemical message is converted back into an electrical impulse and the process of electrical transmission begins.

Question 4

What are neurotransmitters?

Answer 4

Neurotransmitters are chemicals that diffuse across synapse to the next neuron in the chain.
Each neurotransmitter has its own specific molecular structure that fits perfectly into a post-synaptic receptor site like a lock and key .

Question 5

What are two examples of neurotransmitters and what are their functions?

Answer 5

Acetylcholine - found where a motor neuron meets a muscle and causes muscles to contract.
Serotonin - affect mood and social behaviour which is why it has been implicated as a cause of depression.

Question 6

What is meant by citation and inhibition in neurotransmission?

Answer 6

Neurotransmitters generally have either an excitatory or inhibitory effect on the neighbouring neuron.

Question 7

What is meant by excitatory neurotransmitters?

Answer 7

Excitatory means neurotransmitters increase the likelihood of neurons firing by making the post-synaptic neuron more positively charged.

Question 8

What is meant by inhibitory neurotransmitters?

Answer 8

Inhibitory means neurotransmitters decrease the likelihood of a neuron firing by making the post synaptic neuron more negatively charged.

Question 9

What is summation?

Answer 9

Excitatory and inhibitory influences are summed and must reach a certain threshold in order for the action potential of the post synaptic neuron to be triggered.
If the net effect of the neurotransmitters is inhibitory, then the post synaptic neuron is less likely to fire. It is more likely to fire if the net effect is excitatory.