Lecture 21: Bioelectricity

Question 1

What charge do cations have?

Answer 1

Positive.

Question 2

Which two cations are used to create charge in a cell?

Answer 2

Na+ and K+

Question 3

What charge do anions have?

Answer 3

Negative.

Question 4

What part of a cell acts as an insulator?

Answer 4

The lipid bilayer (membrane).

Question 5

What is the concentration of Na+ and K+ in the ECF?

Answer 5

Na+ : 142mM

K+ : 4mM

Question 6

What is the concentration of Na+ and K+ in the ICF?

Answer 6

Na+ : 12mM

K+ : 150mM

Question 7

What is the RMP of a cell?

Answer 7

-70mV

Question 8

Which channels are open/closed at RMP?

Answer 8

Most Na+ channels closed, some K+ channels open.

Question 9

What exchange takes place at ATPase?

Answer 9

The Na+ K+ pump shifts 3x Na+ cations out of the cell and 2x K+ cations in.

Question 10

Does ATPase require energy?

Answer 10

Yes

Question 11

Are neurons usually at RMP?

Answer 11

No

Question 12

Which channels are open when a cell is DEPOLARISED?

Answer 12

Na+ channels open, positive charges move in.

Question 13

Which channels are open when a cell is REPOLARISED/HYPERPOLARISED?

Answer 13

K+ channels open, positive charges move out.

Question 14

When a cell is depolarised it is in a _________ state.

Answer 14

Excitatory. It is less negative than RMP.

Question 15

When a cell is hyperpolarised it is in an _________ state.

Answer 15

Inhibitory. It’s more negative than RMP.

Question 16

What is the threshold potential?

Answer 16

-59mV

Question 17

What is the temporary maximum depolarisation of a cell?

Answer 17

+30mV

Question 18

What are the 4 types of potential in a cell?

Answer 18

Resting, Local, Threshold and Action.