Nerve transmission and ap

Question 1

What is the first stage of nerve transmission

Answer 1

Polarization
-Na+/K+ pump 3Na in 2 K out in active transport (REQUIRES ATP)
-K+ slow leak channels (passive transport)
-Na+ gates involved in passive transport
-Na+ channel normally impermeable to Na.

Question 2

What is the second stage of nerve transmission

Answer 2

Depolarization
-Stimulus alters the 3º structure of Na gate
-Becomes permeable to Na
-Na floods in (passive) making ICF postive

Question 3

What is the third stage of nerve transmission

Answer 3

Repolarization
-Depolarization causes K+ channels to alter their shape
-K+ flows out
-Inside becomes more negative again
-Overshoot prevent signals from going back.

Question 4

What is in the fourth and last stage of nerve transmission

Answer 4

Refractory period.
Na/K pump

Question 5

What is the all or non principle

Answer 5

The power of the stimulus is not proportional to the power of the action potential.