Nevous System 2

Question 1

What 3 structures does the cell membrane contain

Answer 1

-sodium ion channels
-potassium ion channel
-sodium potassium pump

Question 2

Describe the structure of sodium ion channels

Answer 2

Gated protein channel that can open and close to allow sodium ions into the cell- facilitated diffusion

Question 3

Describe the structure of potassium ion channels

Answer 3

Gated channel protein that can open and close to allow potassium ions into the cell- facilitated diffusion

Question 4

Describe the structure of a sodium potassium pump

Answer 4

Active transport of sodium potassium ions, 3k+ out for every 2Na+ in using ATP as an energy source

Question 5

What is meant by ‘self propagating wave of electrical activity that travels along an axon membrane’

Answer 5

It generates itself and doesn’t require any external forces. It is a temporary reversal of the electrical potential difference across the axon membrane

Question 6

What does polarised mean

Answer 6

There is a difference in voltage between the inside and outside of the axon

Question 7

When is an action potential triggered

Answer 7

If the membrane at the axon hillock reaches a certain threshold

Question 8

What is failed initiation

Answer 8

When the nerve doesn’t transmit the signal

Question 9

Describe the first stage of action potential- depolarisation

Answer 9

Voltage sensitive na+ channels open and na+ floods in to the neuron, down its concentration gradient

Question 10

Describe the second stage of action potential- repolarisation

Answer 10

Voltage sensitive k+ channels open and k+ moves out of the neuron down the concentration gradient but causes an overshoot (hyperpolarisation)