NERVE PHYSIOLOGY- Action potential

Question 0

Parts of a neuron

Answer 0

Dendrites
Cell body
Axon

Question 1

What is a neuron?

Answer 1

Functional unit of nerve tissue

Question 2

Describe a dendrite

Answer 2

Shorter, numerous processes

Afferent nerve

Question 3

Part of neuron that contains the nucleus, mitochondria and receive stimuli from dendrites

Answer 3

Cell body

Question 4

What is an axon

Answer 4

Single long cylindrical extension of the cell

Efferent nerve

Question 5

Dendrite vs axon

Answer 5

Dendrite - afferent towards

Axon - efferent away

Question 6

Nerve coverings

Answer 6

Myelin sheath
Neurolemma
Nodes of ranvier

Question 7

Describe myelin sheath

Answer 7

SERVES AS INSULATOR
Schwann cells wrapped spirally
Prevents movement of ions

Question 8

Outermost covering of a nerve

Answer 8

Neurolemma

Question 9

Describe nodes of ranvier

Answer 9

Junc bet 2 succ schwann cells

Small uninsulated area

Question 10

Contains sphingomyelin

Answer 10

Schwann cells

Question 11

What is an impulse?

Answer 11

It is an electric current aka as action potential

Question 12

What is an action potential??

Answer 12

Changes in the membrane potentials will open the membrane channels for exchange of ions

Question 13

Channels that are present in the membrane

Answer 13

Voltage gated K channels
Na channel slow gate/one
Na channel fast gate/one
K leak channel
Na K pump

Question 14

It is open only if needed, closed during the resting stage.

Answer 14

VOLTAGE GATED K CHANNEL

Question 15

What is a voltage gated K channel

Answer 15

It is a channel that opens slowly when membrane potential rises from -90MV to zero

It allows increase K diffusion OUTWARD

Question 16

Na channel that is open at REST

Answer 16

Na channel SLOW GATE

Question 17

Describe Na channel FAST GATE

Answer 17

It opens during DEpolarization making the membrane permeable to Na ions

Question 18

What is -90MV?

Answer 18

The nerve fiber is at rest

Or the NEGATIVE RESTING STAGE

Question 19

Describe K leak channel

Answer 19

It is an open and continuous pathway for small K leakage out of the membrane creating a negative resting membrane

Question 20

Describe the sodium potassium pump

Answer 20

It is an electrogenic pump that continuously pump 3 Na ions out and 2 K ions into the cell leaving a net deficit of positive ions on the inside

Question 21

What is depolarization

Answer 21

Positive charged inside the cell membrane

Question 22

Summary of the sequences of events in the propagation of impulse

Answer 22

Permeability to Na - Na influx - depolarization
Permeability to K - K efflux - repolarization
Na inactivity - stop Na influx - repolarization
NaK pump - 3 Na out/ 2 K in - Negative resting membrane potential

Question 23

Give the Sequence of events in propagation of impulse

Answer 23

Resting stage
The fast gate of Na channel opens in the presence of stimulus
(Depolarization)
Na channel closes
Rapid diffusion of K ions to the exterior
(repolarization)
Na K pump continuously pump 3 Na ions out and 2 K ions in

Question 24

Depolarization vs Repolarization

Answer 24

De- positively charged inside

Re- nerve fiber goes back to negative resting membrane potential or stage

Question 25

What is an action potential

Answer 25

Changes in membrane potential.
There is a certain movt of ions

• reversal in the electrical potential across a membrane when activated by a stimulus

Question 26

Ways on how to regulate func of other system

Answer 26

Nervous control

Hormonal control