nueronal communication

Question 1

Explain the effect of sweating will have on the body (2 marks )

Answer 1

1. evaporation will have a cooling effect / reduce ( body) temperature
2. heat, taken from the body/blood/skin is needed/used for evaporation
3. idea that water had a high latent heat of vaporisation

Question 2

Suggest why shivering occurs during fever (1 mark )

Answer 2

idea that to increase the body temperature as it is lower than the new set point ( even though body is hot )

Question 3

explain the “all or nothing “ law (1 mark)

Answer 3

if the stimulus is not strong enough/ threshold is not reached/ depolarisation is insufficient an action potential is not generated

Question 4

why is the pacinian corpuscle described as a transducer ? (1 mark)

Answer 4

it converts energy ( mechanical ) into another form of energy (electrical)

Question 5

Suggest an explanation for the fact that action potentials are not generated constantly whilst wearing clothes. ( 1 mark )

Answer 5

1. Sodium channels remain open and resting potential not re-established.
2. idea of ions being in the wrong place for correct ion movement

Question 6

Outline the roles of synapses in the nervous system. (3 marks)

Answer 6

1. allows , neurones to communicate
2. ensure transmission in one direction only
3. allows, impulses from more than one neurone to be passed to a single neurone
4. permits memory
5. allows many low level stimuli to be amplified

Question 7

Name one chemical that transfers a nerve impulse from one to another (1 mark)

Answer 7

acetylcholine

Question 8

Comment on the relationship between the strength of a stimulus and the resulting action potential (2 marks )

Answer 8

1. only stimulus that reach threshold value produce an action potential
2. when stimulate action potential edit her occurs or doesn’t ( all or nothing law )
3. a strong stimulus produces many action potentials

Question 9

Describe and explain how the resting potential is established and how it is maintained in a sensory neurone. (4 marks)

Answer 9

PUMPING/ ACTIVE
1.sodium potassium pump uses atp
2. pump actively lives Na+ out and K+ in
PASSIVE/DIFFUSING
3. K+ diffusing back out of cell 
4. membrane has less permeability to Na+ 
5. Voltage gate Na+ channels closed.

Question 10

State the name given to cells of the body communicating with each other (1 mark)

Answer 10

cell signalling

Question 11

Outline how the first neurone communicates with the second neurone across the gap (3 marks)

Answer 11

1. neurotransmitter released from pre-synaptic membrane
2. diffuses across syntactic cleft
3. attaches to receptors on post-synaptic membrane
4. neurotransmitter broken down in cleft

Question 12

State 3 differences in the structure of motor and sensory neurones (3 marks)

Answer 12

motor neurone vs sensory neurone
m=cell body end of neurone , s=middle of neurone

m=longer axon
s=shorter axon

m=no dendron
s=dendron present