Types of gated (regulated) channels & Action Potentials

Question 1

opens in response to a change in voltage (charge)

Answer 1

voltage-gated

Question 2

responds (opens/closes) because of a neurotransmitter, hormone or ion.

Answer 2

ligand-gated aka chemically or transmitter gated

Question 3

responds (opens/closes) because of pressure, vibration, or stretch

Answer 3

mechanically gated

Question 4

the movement of ions

Answer 4

electrochemical gradient

Question 5

What are the 2 reason the movement of ions occurs?

Answer 5

1. due to concentration gradients

2. charge differences (negative attracted to positive ions)

Question 6

What is the voltage of the resting membrane potential in milivolts?

Answer 6

overall the cell is negative for -40 to -90 milivolts

-70 is average

Question 7

When the cell is polarized where is it more negative?

Answer 7

on the inside vs the outside

Question 8

In a polarized cell how is K+ and Na+ on the inside of the cell?

Answer 8

K+ high

Na+ low

Question 9

In a polarized cell is the plasma membrane more permeable to sodium or potassium?

Answer 9

it is 50-100 times more permeable to potassium (K+)

Question 10

There is a sodium and potassium pump, what does it maintain?

Answer 10

the chemical and electrical potential

Question 11

changes in the resting potential, the cell becomes depolarized (less negative) or hyperpolarized (more negative) by local currents

Answer 11

graded potential

Question 12

What happens to the cell in a graded potential?

Answer 12

depolarized (more positive)

hyperpolarized (more negative)

Question 13

Do all graded potentials lead to an action potential? Why?

Answer 13

No, a threshold must be met