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?

 

 

 

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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

 
 

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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

 

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20

cardiac action potential duration?

 

200 - 400 ms

(depending on species and heart rate)

 

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21

What are the two types of electrical activity?

 
 

Action potential

Graded depolarisation

 
 

22

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

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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 

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