ACTION POTENTIAL

Question 1

Excitable tissues Are tissues that are able to——-

Answer 1

generate and transmit electrochemical impulses

Question 2

Which are excitable and which are not?.

nerve cells
Smooth muscle
 git
Cardiac muscle
adipocytes
Skeletal muscle 
Rbc

Answer 2

nerve cells,muscle cells are excitable while git, adipocytes, rbc are not

Question 3

Which has a more positive rmp?.

Excitable or non-excitable cells

Answer 3

Non-excitable

Question 4

Where can we find the following more..ecf or ICf?

Na 
Cl
K
Pr-
Hco3-
Ca

Answer 4

ecf has more Hco3, Na, Cl, and Ca than ICf

Question 5

Define the GIBBS DONAN EQUILLIBRUM

Answer 5

2 solutions. Separated by a selectively permeable .membrane . An equilibrium has to be reached. I.e the chemical and electrical energies on both sides would be equal and opposite to each other

Question 6

NERNST POTENTIAL aka ——- , is the ——-

Answer 6

equilibrium potential

potential that would be reached that would prevent the diffusion (net diffusion) of an ion

Question 7

GOLDMAN’s equation aka ——- is use to ——

Answer 7

GHK equation

Calculate rmp

Question 8

GHK equation is dependent on 3 factors. List them

Answer 8

1) polarity of each ion
2) membrane permeability
3) ionic conc

Question 9

at the electrochemical equilibrium , there is a —— between——- which are ___ and ____

Answer 9

balance

2 opposing force

Chemical driving force

Electrical driving force

Question 10

Chemical driving force of an electrochemical gradient is———

Electrical driving force of an electrochemical gradient is———

Answer 10

ratio of conc of ions across the membranes

potential difference across membrane

Question 11

Na+ VOLTAGE-GATED ION CHANNEL has —— gates.

List them, where they are located in relation to the membrane, and another name for them

Answer 11

two

Activation and inactivation gates

• act is outside and inact is inside
• act is called m gate
• inact is called h gate

Question 12

At rest, Na+ channel inactivation gate is——— and activation gate is——

Answer 12

opened

closed

Question 13

At threshold level,Na+channel activation gate —— and Na+ —— will occur(Na+ channel opens—-)

Answer 13

opens

influx

fast

Question 14

when AP is approaching +30, Na+channel’s inactivation gate—— and Na influx ——-

Answer 14

closes

stops

Question 15

Na channel’s Inactivation gate will not reopen until —— is reached

Answer 15

reopen

resting membrane potential

Question 16

K+ VOLTAGE-GATED ION CHANNEL has—- gate

Answer 16

only one

Question 17

At rest, K+ channel is ———

Answer 17

closed

Question 18

At +3V K+ channel ——- at a—— rate

Answer 18

open up

slow

Question 19

After reaching the rmp, slow K+ channels may ——, causing further ——

Answer 19

remain open

hyperpolarisation

Question 20

During the Absolute refractory period , nerve membrane cannot be excited again, Because of the ——— gate

Answer 20

closure of inactivation

Question 21

During the Relative refractory period , nerve membrane can be excited by ——-stimuli

Answer 21

supra threshold

Question 22

Effect of membrane stabilizers and destabilizers on excitability

Answer 22

Membrane stabilisers decrease excitability

Membrane destabilizers increase excitability

Question 23

Which are stabilizers and which are destabilizerstab

Acidosis 
Alkalosis
Hypoxia
Increased serum  K+ 
Decreased serum  K+
Increased serum  Ca++
Decreased serum  Ca++ 
Local  anaesthetics

Answer 23

Stabilizer
Destabilizer
Stabilizer
Destabilizer
Stabilizer 
Stabilizer 
Destabilizer 
Stabilizer

Question 24

How does Increased serum Ca+ stabilize the membrane?

Answer 24

Hypocalcaemia causes membrane instability and spontaneous activation of nerve membrane–Reduced Ca level facilitates Na entry–Spontaneous activation