The neuron (U3 AOS 1)

Question 1

What are the three types of neurons

Answer 1

Sensory neurons, motor neurons and interneurons.

Question 2

What is the role of a dendrite

Answer 2

Extension of a neuron that first receives information from other neurons and transmits it to the soma.

Question 3

What is the role of the soma?

Answer 3

Combines the neural information from dendrites and sends it to the axon.

Question 4

What is the role of the axon?

Answer 4

Transmits a message from the soma to other cells in the body in the form of an electrical nerve impulse.

Question 5

What is the role of the myelin sheath?

Answer 5

It is a white, fatty covering that helps insulate the axon of one neuron from others.
This allows faster transmission of the electrical impulses across the nerve cells.

Question 6

What do the axon terminals contain?

Answer 6

A tip called a terminal button which contain neurotransmitters.

Question 7

Explain the process of the transmission of information within a neuron.

Answer 7

At rest, the neuron has a ‘resting potential’. When activated an ‘action potential’ travels down the neuron from the soma towards the terminal buttons via the axon.

Question 8

What is an action potential?

Answer 8

An electrical current/impulse that travels within a neuron

Question 9

Is communication within the neuron electrical or chemical?

Answer 9

Electrical

Question 10

What is a neurotransmitter?

Answer 10

A chemical messenger synthesised within a pre-synaptic neuron and transmitted across the synpase.

Question 11

Is communication between neurons electrical or chemical?

Answer 11

Chemical

Question 12

How are neurotransmitters involved in the transmission of information between neurons?

Answer 12

They are released from the pre-synaptic neuron, pass across the synaptic gap and then land onto a receptor site of a dendrite of the post-synaptic neuron.

Question 13

With reference to glutamate, outline the processes involved in successful neural transmission once the neural impulse has reached the axon terminal. In your response, refer to the lock-and-key process.

Answer 13

Glutamate is released into the synaptic gap from the vesicles of the pre-synaptic neuron.
Glutamate acts as a key where the complementary receptor site acts as a lock.
Glutamate then binds with the complementary receptor sites of the post-synaptic neuron.
Glutamate increases the likelihood of the post-synaptic neuron firing an action potential.

Question 14

What is an excitatory effect and give an example of one.

Answer 14

It is an effect that stimulates the postsynaptic neuron to perform their functions. Makes neurons more likely to create an action potential.
E.g, glutamate

Question 15

What is an inhibitory effect and give an example of one.

Answer 15

Blocks/prevents postsynaptic neurons from firing. Makes neurons less likely to fire an action potential.
E.g, GABA

Question 16

What is the role of an agonist?

Answer 16

A substance or drug that increases the release of a neurotransmitter. This causes the post-synaptic neuron to fire an action potential.

Question 17

What is the role of an antagonist?

Answer 17

Inhibits the release of neurotransmitters or blocks the receptor sites for neurotransmitters.

Question 18

What is Parkinson’s disease?

Answer 18

A neurodegenerative disorder characterised by chronic and progressive changes in the brain due to deterioration to neurons leading to impaired movement.

Question 19

What certain areas of the brain are affected by PD. Explain their relevance in contributing to PD.

Answer 19

The substantia nigra and basal ganglia and corpus striatum are affected.
The substantia nigra is responsible for neurons producing and releasing dopamine (used for controlling movement). As the neurons deteriorate because of PD, their capacity to produce dopamines diminish.
The basal ganglia and corpus striatum structures allow smooth regular movements of muscles. With diminishing dopamine levels, the communication between the two is impaired.

Question 20

List 2 of each primary motor symptoms, secondary motor symptoms and non-motor symptoms of PD.

Answer 20

Primary motor symptoms:
- Unpredictable tremors
- Rigidity
- Bradykinesia
- Reduced coordination and balance

Secondary motor symptoms:
- Reduced control over facial muscles
- Pain and discomfort in limbs

Non-motor symptoms:
- Anxiety
- Depression

• Difficulties with communication, limiting person’s ability to socialise
• Social isolation (due to feeling embarassed)

Question 21

How does PD affect someone regarding to dopamine.

Answer 21

The amount of dopamine available lessens and thus the dopamine available for motor activity is lower. This leads to slowness of voluntary movement and difficulty starting new movements.