Lecture 6 - excitability of muscle cells Flashcards Preview

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Flashcards in Lecture 6 - excitability of muscle cells Deck (24):
1

Nernst Equation?

 

 

 

2

What is the [Na] in the intracellular matrix(mM) ?

 

8-10 mM

 

3

What is the [Na] in the extracellular matrix?

 

140 mM

 

4

What is the [K] in the extracellular matrix(mM)?

 

4-5 mM

 

5

What is the [Cl] in the extracellular matrix(mM)?

 

140 mM

 

6

What is the [Ca] in the extracellular matrix(M)?

 

10-3 M

 

7

What is the [Mg] in the extracellular matrix(mM)?

 

1

 

8

What is the [K] in the intracellular matrix(mM)?

 

120-140 mM

 

9

What is the [Cl] in the intracellular matrix(mM)?

 

30

 

10

What is the [Ca] in the intracellular matrix(M)?

 

10-7

 

11

What is the [Mg] in the intracellular matrix(mM)?

 

1

 

12

A large number of ions move with each action potential.

 

FALSE.

 

 

only a small number of ions move with each action potential.

 

13

The bulk concentrations do not change significantly in a single excitation.

 

TRUE

 

14

What are the 3 classes of ion translocation proteins?

 

Ion channels

Ion pumps

Ion exchangers/symports

 

 

15

What are the 3 states that ion channels can exist in?

 
 
 

closed 

open

inactivated

 
 
 

16

What is needed the turn a inactivated channel into a closed channel?

 

Repolarisation

 

17

Neuronal action potential duration?

 
 

500µs

 
 

18

What is the refractory period?

 

a period immediately following stimulation during which a nerve or muscle is unresponsive to further stimulation.

 

19

 skeletal action potential duration?

 

1 ms

 

20

cardiac action potential duration?

 

200 - 400 ms

(depending on species and heart rate)

 

21

What are the two types of electrical activity?

 
 

Action potential

Graded depolarisation

 
 

22

Basic Structure of Na, Ca (and many K) channels ??

23

What opens ion channels? 

Voltage 

-

Ligands  

ACh

GABA

ATP

Glutamate

-

Other things:

Stretch

Light

2nd messengers

Temperature

24

Why is the cardiac action potential so long? 

 

(i) Prevents tetany
(ii) Protectsagainstre-entrant arrhythmias