Phase 2 SAQ paper

Question 1

define absolute refractory period

Answer 1

the period immediately following the firing of a nerve fiber when it cannot be stimulated no matter how great a stimulus is applied

Question 2

relative refractory period

Answer 2

the period shortly after the firing of a nerve fiber when partial repolarization has occurred and a greater than normal stimulus can stimulate a second response

Question 3

what channel opens when the action potential propagates and what does this do to the value of the membrane potential?

Answer 3

voltage-gated sodium channels. this makes the membrane potential become more positive

Question 4

myelin sheeth producing cells in the CNS

Answer 4

oligodendrocytes

Question 5

myelin sheath producing cells in the PNS?

Answer 5

schwann cells

Question 6

why does myelin speed up nerve conduction

Answer 6

Myelin is a good insulator, but there are openings (nodes) between the sheath wrappings. The impulse “jumps” from node to node (saltatory conduction) instead of having to flow down the entire length of the axon

Question 7

what are the 2 hormones produced in the AP that act on the ovary

Answer 7

leutenising hormone and folicular stimulating hormone

Question 8

2 types of cells in the ovary

Answer 8

granulosa

theca interna

Question 9

2 effects of oestrogen on the endometrium?

Answer 9

growth of smooth uterine muscle

softening of the pelvic and cervical ligaments