Neurons And Synapses

Question 1

What does the Central nervous system consist of?

Answer 1

The brain and the spinal cord

Question 2

Describe the process of Neurone transmission (3 marks)

Answer 2

An electrical impulse is received from the dendrites on the presynaptic neurone. This impulse is controlled by the nucleus, so that it travels from the cell body through to the axon hillock. The axon is made up of small cells, called Schwann cells and theses are surrounded by the myelin sheath that acts as an insulator to speed up the travel of the impulse between each cell. Once the impulse has travelled down the axon it is transported down the end of the axon, known as the axon terminals which contain neurotransmitters. At the end of each axon terminal is a synapse, that neurotransmitters have to travel across to transmit the message to the post synaptic neurone.

Question 3

Describe the process of synaptic transmission (3 marks)

Answer 3

An electrical impulse travels down the presynaptic neurone and depolarises the neurone. This causes the synaptic vesicles containing neurotransmitters to move down the axon terminal until it binds to the presynaptic membrane. Once this occurs, neurotransmitters diffuse into the synapse. The neurotransmitters bind to receptors on the postsynaptic membrane. The neurotransmitters send a particular message to the next neurone that helps regulate a behaviour, movement, emotion depending on whether the neurotransmitter is inhibitory or excitatory.

Question 4

What is an excitatory neurotransmitter?

Answer 4

A neurotransmitter that increases activity between neurones

Question 5

What is an inhibitory neurotransmitter?

Answer 5

A neurotransmitter that decreases activity between neurones

Question 6

Give an example of an excitatory neurotransmitter?

Answer 6

Dopamine

Question 7

Give an example of a inhibitory neurotransmitter

Answer 7

GABA