Cells of the Nervous System and Neurotransmitters at Synapses

Question 1

Name three structural components
of a neurone

Answer 1

Dendrites, cell body and axon

Question 2

State the function of the
dendrite

Answer 2

Receive electrical impulses, either excitatory or inhibitory

Question 3

State the function of the cell
body

Answer 3

The cell body contains the nucleus
and connects the dendrites and the
axon

Question 4

State the function of the
axon

Answer 4

An axon carries electrical impulses
away from a cell body towards another dendrite/muscle fiber

Question 5

State the pathway of an
electrical impulse through a neuron

Answer 5

Dendrite cell body axon

Question 6

Name the structure surrounding an
axon and explain its function

Answer 6

A myelin sheath insulates the axon and
increases the speed of impulse conduction

Question 7

Give the name of the cells that
produce the myelin sheath and
support neurons

Answer 7

Glial cells

Question 8

At what stage does myelination occur in the body?

Answer 8

From birth to adolescence

Question 9

Explain why responses in the first two years of life are not as rapid or coordinated as those of an older child or
adult

Answer 9

Myelination is incomplete, reducing the
speed of impulse conduction

Question 10

Suggest an effect of diseases
that destroy the myelin sheath

Answer 10

The individual may experience a loss
of co-ordination

Question 11

State the name given to the area
where neurons connect with other
neurones or muscle fibres

Answer 11

The synapse/synaptic cleft

Question 12

Name the chemicals that cross
synapses

Answer 12

Neurotransmitters

Question 13

State the function of
neurotransmitters

Answer 13

They relay impulses across the synapse

Question 14

Describe the role of neurotransmitters on the arrival of an impulse

Answer 14

They are released from vesicles into the
a synaptic cleft on the arrival of an impulse

Question 15

By which process do
neurotransmitters cross a
synapse?

Answer 15

diffusion

Question 16

State what happens to
neurotransmitters after
crossing a synapse

Answer 16

They bind to receptors on the membrane
of post-synaptic neurons or muscle fibres

Question 17

State how neurotransmitters are
removed from a synapse

Answer 17

By enzymes or re-uptake

Question 18

Explain why neurotransmitters
are removed from a synapse

Answer 18

Prevent repeated stimulation of a
neuron

Question 19

Name the cell structures that
determine whether a signal is
excitatory or inhibitory

Answer 19

Receptors

Question 20

Describe how synapses can filter out
weak stimuli arising from insufficient
secretion of neurotransmitters

Answer 20

A minimum number of neurotransmitter molecules must attach to receptors

reach the threshold on the postsynaptic membrane

transmit the impulse.

Question 21

Suggest how weak stimuli may
release enough neurotransmitter
to trigger an impulse

Answer 21

The summation of a series of weak
stimuli may release enough neurotransmitter to reach the threshold

Question 22

State the neural pathway which
typically utilises summation

Answer 22

Converging

Question 23

Name the neurotransmitters that
stimulate neurones involved in
reducing the intensity of pain

Answer 23

Endorphins

Question 24

Describe how endorphin production
changes in response to severe
injury, prolonged and continuous exercise,
stress and certain foods such as chocolate

Answer 24

Increases

Question 25

Give examples of activities, linked to the feeling of pleasure, that may account for increased levels of endorphin

Answer 25

Eating, sex and prolonged exercise

Question 26

Name the neurotransmitter that induces feelings of pleasure and reinforces particular behaviours by activating the reward pathway in the
brain

Answer 26

dopamine

Question 27

Give an example of a beneficial
behaviour which can activate the
reward pathway

Answer 27

Eating

Question 28

Name the two types of drugs used
to treat neurotransmitter-related
disorders

Answer 28

Agonists and antagonists

Question 29

Describe the function of an agonist

Answer 29

Bind to and stimulate specific receptors, mimicking the action of a neurotransmitter at a synapse

Question 30

Describe the function of an
antagonist

Answer 30

Bind to and block specific receptors
therefore blocking the action of a
neurotransmitter at a synapse

Question 31

Describe how drugs other than agonists or antagonists affect neurotransmitters at the synapse

Answer 31

inhibit enzymes that degrade neurotransmitters

ihibit reuptake of the neurotransmitter at the synapse,
- causing enhanced effect

Question 32

State 4 ways recreational drugs can
affect an individual

Answer 32

Mood, cognition, perception or behaviour

Question 33

State which neurotransmitter
pathway in the brain is often
affected by recreational drugs

Answer 33

Reward pathway

Question 34

State how drug addiction is caused

Answer 34

Repeated use of drugs acting as antagonists,
block specific receptors causing the nervous
system to increase both the number and
sensitivity of the receptors

Question 35

Explain why sensitisation of
receptors leads to addiction

Answer 35

Individual craves more drugs to bind to
the receptors

Question 36

State how drug tolerance is caused

Answer 36

Repeated use of drugs that act as agonists stimulate specific receptors causing the nervous system to decrease both the number and sensitivity
of these receptors

Question 37

Explain why desensitisation of
receptors leads to drug tolerance

Answer 37

An individual must take more drug to get
an effect