Unit Three - Key Area 4

Question 1

What are neurons?

Answer 1

Neurons are cells within the nervous system that transmit information to other nerve cells, muscle, or gland cells.

Question 2

What is a neuron made up of?

Answer 2

axon, dendrites and a cell body

Question 3

What is the myelin sheath?

Answer 3

Myelin sheath insulates the axon and increases the speed of impulse conduction.

Question 4

What do glial cells do?

Answer 4

Glial cells produce the myelin sheath and support neurons.

Question 5

How does a loss of co-ordination occur?

Answer 5

when certain diseases destroy the myelin sheath

Question 6

What does myelin enable?

Answer 6

Myelin enables nerve cells to transmit information faster and allows for more complex brain processes

Question 7

Why is the myelination process important?

Answer 7

The myelination process is vitally important to a healthy central nervous system functioning.

Question 8

What happens at a synaptic cleft (synapse).

Answer 8

Neurons connect with other neurons or muscle fibres

Question 9

What do neurotransmitters do?

Answer 9

relay impulses across the synaptic cleft

Question 10

Where are neurotransmitters stored?

Answer 10

in vesicles in the axon endings of the pre-synaptic neuron.

Question 11

Describe the process of neurotransmitters at a synaptic cleft

Answer 11

They are released into the cleft on arrival of an impulse. They diffuse across the cleft and bind to receptors on the membrane of the postsynaptic neuron.
The electrical impulse changes to a chemical impulse as it is carried across the synaptic cleft.

Question 12

What do receptors determine?

Answer 12

whether a signal is excitatory or inhibitory.

Question 13

What happens in the process of summation?

Answer 13

A series of weak stimuli can combine to reach the firing threshold in the post-synaptic neuron

Question 14

What are endorphins?

Answer 14

Endorphins are neurotransmitters that stimulate neurons involved in reducing the intensity of pain.

Question 15

What are increased endorphins levels linked to?

Answer 15

The feelings of pleasure obtained from activities such as eating, sex and prolonged exercise.

Question 16

When does endorphin production increase?

Answer 16

In response to severe injury, prolonged and continuous exercise, stress and certain foods.

Question 17

What is dopamine?

Answer 17

A neurotransmitter that induces feelings of pleasure and reinforces particular behaviour by activating the reward pathway of the brain.

Question 18

What does the reward pathway involve?

Answer 18

neurons which secrete or respond to dopamine.

Question 19

When is the reward pathway activated?

Answer 19

The reward pathway is activated when an individual engages in a behaviour that is beneficial to them, for example when eating when hungry.

Question 20

What are agonists?

Answer 20

Agonists are chemicals that bind to and stimulate specific receptors mimicking the action of a neurotransmitter at a synapse.

Question 21

What are antagonists?

Answer 21

Antagonists are chemicals that bind to specific receptors blocking the action of a neurotransmitters at a synapse.

Question 22

How can other drugs act on neurotransmitters?

Answer 22

other drugs act by inhibiting the enzymes that degrade neurotransmitters of by inhibiting reuptake of the neurotransmitter at the synapse causing an enhanced effect.