Neural electrophysiology

Question 1

electrical potential

Answer 1

difference in concentration of charged particles between one point and another
- form potential energy and can produce a current

Question 2

current

Answer 2

flow of charged particles from one point to another

Question 3

polarized

Answer 3

if something has a potential

Question 4

resting membrane potential (RMP)

Answer 4

charge difference across the plasma membrane
~70 mV is resting neuron
- more negative charged particles on inside of membrane than outside

Question 5

potassium ions…

Answer 5

have greater influence on RMP because plasma membrane is more permeable to K+

Question 6

Sodium potassium pump…

Answer 6

accounts for about 70% of energy requirement of nervous system

Question 7

local potential

Answer 7

short rate change in voltage

Question 8

graded

Answer 8

vary in magnitude according to strength of stimulus

Question 9

decremental

Answer 9

get weaker as they spread from point of origin

Question 10

reversible

Answer 10

if stimulation ceases, cation diffusion out of cell quickly returns membrane voltage to resting potential

Question 11

excitatory

Answer 11

depolarize a cell, makes neuron more likely to produce an action potential

Question 12

inhibitory

Answer 12

caused by hyper polarized cell
- more negative membrane

Question 13

action potential

Answer 13

more dramatic change produced by channels in membrane
- only where there is a high enough density of channels

Question 14

action potential details

Answer 14

• all or non law, has two reach threshold
• not decremental, don’t get weaker with distance
• irreversible, if threshold is reached and action potential goes to completion it can’t be stopped

Question 15

refractory period

Answer 15

few milliseconds after action potential where its different/impossible to stimulate region to fire again
- absolute: no stimulus can trigger it
- relative: w/strong stimulus it can be triggered

Question 16

continuous conduction

Answer 16

uninterrupted wave of electrical excitation all along axon
- in unmyelinated axon

Question 17

saltatory conduction

Answer 17

leaping/jumping of signal,
-nerve signal has to transverse distance from one node to the next