nervous system 4

Question 1

what is the point where nerve cell first becomes activated

Answer 1

initial segment

Question 2

generation of action potential (9)

Answer 2

1. gates of Na+ channels open
2. Na+ rushes into the cell
3. Inside becomes positively charged
4. Na+ gates close
5. K+ gates open
6. outlfow of K+ ions
7. inside becomes negatively changed again
8. K+ gates close
9. Na+/K+ channels pump the ions back to their original state at rest

Question 3

what does the term propagation mean?

Answer 3

activation of the initial segment triggers the activation of subsequent sections.

Question 4

benefits to myelination

Answer 4

transmission much faster in myelinated axon
uses less energy ( less pumps active)
mylinated axons have exposed areas of axon and the impulse jumps from area to area

Question 5

what are the exposed area of axon called

Answer 5

nodes of ranvier

Question 6

the recovery period is called

Answer 6

Refractory period

Question 7

2 stages of ‘recovery period’

Answer 7

absolute refractory period - recovery stage during which the nerve cell cannot be activated (all Na+ inside cell)
relative refractory period - recovery period during which the nerve cell can be activated but only in response to a stimulus that is higher than normal.