Cells of the nervous system and neurotransmitters at synapses

Question 1

What is a neuron?

Answer 1

a specialised cell that is designed to transmit information to other nerve cells, muscle, or gland cells

Question 2

What are neurons made up of?

Answer 2

Dendrites, the cell body and axons

Question 3

What does the myelin sheath do?

Answer 3

it insulates the axons and increases the speed of impulse conduction.

Question 4

What do glial cells do?

Answer 4

They produce the myelin sheath and support neurons

Question 5

Describe myelination

Answer 5

The myelination process is vitally important to the central nervous system functioning. It continues from birth to adolescence.

Question 6

How can the myelin sheath be damaged?

Answer 6

Some diseases destroy the myelin sheath and this causes loss of coordination.

Question 7

Name an example of a disease that can do this

Answer 7

Multiple sclerosis

Question 8

What do neurotransmitters do?

Answer 8

They relay impulses across the synaptic cleft

Question 9

Where are neurotransmitters stored?

Answer 9

They are stored in vesicles in the axon endings of the pre-synaptic neuron.

Question 10

Describe how neurotransmitters work

Answer 10

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.

Question 11

What happens to the impulse as it goes across the synaptic cleft?

Answer 11

The electrical impulse changes to a chemical impulse.

Question 12

What do receptors do?

Answer 12

They will determine whether a signal is excitatory or inhibitory.

Question 13

What is an example of a receptor?

Answer 13

It promotes an action/production of a substance or prevents a response/inhibit production of a substance.

Question 14

What can be done to prevent continuous stimulation of postsynaptic neurons?

Answer 14

quickly remove the neurotransmitters by enzymes or reuptake the neurotransmitters.

Question 15

How do you filter the weak stimuli?

Answer 15

A minimum number of neurotransmitter molecules must attach to receptors in order to reach the threshold on the postsynaptic membrane to transmit the impulse. This mechanism prevents the generation of impulses from weak/harmless stimuli.

Question 16

How does a series of weak stimuli trigger an impulse?

Answer 16

A series of weak stimuli can release enough neurotransmitter to trigger an impulse. Convergent neural pathways can release enough neurotransmitter molecules to reach threshold and trigger an impulse.

Question 17

What are endorphins?

Answer 17

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

Question 18

What activities increase the levels of endorphins that are linked with feelings of pleasure?

Answer 18

1. eating
2. sex
3. prolonged exercise

Question 19

what else increases endorphin production?

Answer 19

1. severe injury
2. prolonged and continuous exercise
3. stress
4. certain foods

Question 20

What is dopamine?

Answer 20

Dopamine is a neurotransmitter that induces feelings of pleasure and reinforces particular behaviour bye activating the reward pathway of the brain.

Question 21

What is involved in the reward pathway?

Answer 21

It involves neurons which secrete or respond to dopamine.

Question 22

What are agonists?

Answer 22

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

Question 23

An example of an agonist

Answer 23

morphine action leading to pain relief

Question 24

What are antagonists?

Answer 24

These are chemicals that bind to specific receptors blocking the action of a neurotransmitter at a synapse

Question 25

An example of antagonists

Answer 25

Strychnine poisining

Question 26

What do other drugs do?

Answer 26

They inhibit the enzymes which degrade neurotransmitters or inhibit re-uptake

Question 27

An example of a drug that does this

Answer 27

Cocaine