Physiology Lecture #3

Front 1

the branch of physiology that studies the relationship between electric phenomena and bodily processes

Back 1

electrophysiology

Front 2

the electric activity associated with a bodily part or function

Back 2

electrophysiology

Front 3

capable of generating rapidly changing electrochemical impulses at their membranes

Back 3

nerve and muscle cells

Front 4

these impulses are used to transmit signals along the nerve or muscle membranes

Back 4

nerve and muscle cells

Front 5

local changes in membrane potentials also activate many of the cells functions

Back 5

glandular cells, macrophages, and ciliated cells

Front 6

the typical charge difference observed in any cell that is not electrically excitable

Back 6

resting membrane potential

Front 7

the RMP inside the cell is ___ mV with respect to the potential of the extracellular fluid

Back 7

-70mV

Front 8

caused by an ion concentration difference on the two sides of the membrane

Back 8

diffusion potential

Front 9

K+ concentration inside is (greater/less) than the concentration outside

Back 9

greater than

Front 10

the diffusion potential level across a membrane that exactly opposes the net diffusion of a particular ion thoughout the membrane is called the _____

Back 10

nerst potential

Front 11

determined by the ration of the concentrations of that specific ion on the two sides of the membrane

Back 11

nerst potential

Front 12

gives the calclated membrane potential on the inside of the membrane when two univalent positive ions, sodium and potassium, and one univalent negative ion, chloride are involved

Back 12

goldman equation

Front 13

the most important ions involved in the development of membrane potentials in nerve and muscle fibers, as well as in the neuronal cells in the nervous system

Back 13

Na+, K+, Cl-

Front 14

sodium -potassium pump is called __

Back 14

electrogenic pump

Front 15

ratio of sodium to potassium diffused inside and outside of the cell respectively

Back 15

3 sodium ions 2 potassium ion

Front 16

two factors the contribute to membrane potential

Back 16

1. sodium and potassium
2. NA+ K+ ATPase pump

Front 17

resting membrane potential is always

Back 17

-70mv

Front 18

occurs when a neuron sends information down an axon, away from the cell body

Back 18

action potential

Front 19

an explosion of electrical activity that is created by a depolarizing current, where the nerve and muscle cells resting membrane potential changes

Back 19

action potential

Front 20

simply means that the outside and inside of a cell have a different net charge

Back 20

polarization

Front 21

the change in membrane potential closer to 0mV, when its potential is less negative that the resting level

Back 21

Depolarization

Front 22

for an electrically excitable cell, the potential at which voltage-gated ion channels first open and phase 1 of the action potetial begins

Back 22

threshold

Front 23

the temporary reversal of the membrane potential polarity- that is, when the inside of a cell becomes positive relative to the outside

Back 23

overshoot

Front 24

typically, only observed during late phase 1 and early phase 2 of an action potential

Back 24

overshoot

Front 25

the return of a depolarized or overshot membrane potential towards its resting membrane potential

Back 25

repolarization

Front 26

it usually refers to the events of phase 2 of an action potential

Back 26

repolarization

Front 27

the membrane is __ when the potential is more negative than the resting level

Back 27

hyperpolarization

Front 28

can be found in both graded potentials and late phase2/early phase 3 of an acviton potential

Back 28

hyperpolarization

Front 29

are changes in membrane potential that are confined to a relatively small region of the plasma membrane and occur in varying degrees of strength or magnitude

Back 29

graded potential

Front 30

decrease in magnitude with increasing distance from the site of origin

Back 30

graded potential

Front 31

usually produced when some specific change in the cell's environment acts on a specialized region of the membrane

Back 31

graded potential

Front 32

graded potentials occur in ___

Back 32

dendrites

Front 33

to drive th initial segment to threshold membrane potential in order that an action potential could be generated

Back 33

grated potential

Front 34

deliberately small and temporaty, for maximal control of when to send or not to send signals forward

Back 34

graded potential

Front 35

implies a single potential

Back 35

action potential

Front 36

a programmed sequence of changing membrane potentials, induced by the opening and closing of specialized ion channels to change permeability over a period of several milliseconds

Back 36

action potential

Front 37

before action potential begins,

Back 37

resting state, resting membrane potential

Front 38

the membrane becomes very permeable to sodium ions, allowing termendous numbers of positively charged sodium ions to diffuse to the interior of the axon

Back 38

depolarization

Front 39

in large nerve fibers, the great excess of positive sodium ions moving to the inside causes the membrane potential to actually ___ to the positive state

Back 39

overshoot

Front 40

sodium channels begins to close and the potassium channels open more than normal

Back 40

repolarization stage

Front 41

occur only when the initial stimulus is sufficient to elecvate the membrane potetial beyond the threshold potential

Back 41

all-or none principle

Front 42

stimuli that are just string enough to depolarize the membrane to the threshold potential and elicit an action potential

Back 42

threshold stimuli

Front 43

will not elicit an action potential

Back 43

sub-threshold

Front 44

the excited membrane does not repolarize immediately after depolarization instead, the potential remains on a plateau near the peak of the spike potential for many milliseconds, and only the repolarization begin

Back 44

plateau

Front 45

sodium channels begins to close and the potassium channels open more than normal

Back 45

repolarization stage

Front 46

action potentials are initiated in the ___

Back 46

axon hillock

Front 47

occur only when the initial stimulus is sufficient to elecvate the membrane potetial beyond the threshold potential

Back 47

all-or none principle

Front 48

means that, although the action potential affects all other ion channels nearby, the upstream ion channels cannot open again since they are in their refractory period, so only the downstream channels open causing the action potential to move one-way along the axon

Back 48

refractory period

Front 49

stimuli that are just string enough to depolarize the membrane to the threshold potential and elicit an action potential

Back 49

threshold stimuli

Front 50

will not elicit an action potential

Back 50

sub-threshold

Front 51

necessary as it alls the proteins of voltage sensitive ion channels to restore to their original polarity

Back 51

refractory period

Front 52

sodium channels begins to close and the potassium channels open more than normal

Back 52

repolarization stage

Front 53

the excited membrane does not repolarize immediately after depolarization instead, the potential remains on a plateau near the peak of the spike potential for many milliseconds, and only the repolarization begin

Back 53

plateau

Front 54

occur only when the initial stimulus is sufficient to elecvate the membrane potetial beyond the threshold potential

Back 54

all-or none principle

Front 55

refractory period which typically lasts about 1ms

Back 55

absolute refractory period

Front 56

sodium channels begins to close and the potassium channels open more than normal

Back 56

repolarization stage

Front 57

action potentials are initiated in the ___

Back 57

axon hillock

Front 58

stimuli that are just string enough to depolarize the membrane to the threshold potential and elicit an action potential

Back 58

threshold stimuli

Front 59

refractory period which typically lasts about 3ms

Back 59

relative refractory period

Front 60

occur only when the initial stimulus is sufficient to elecvate the membrane potetial beyond the threshold potential

Back 60

all-or none principle

Front 61

means that, although the action potential affects all other ion channels nearby, the upstream ion channels cannot open again since they are in their refractory period, so only the downstream channels open causing the action potential to move one-way along the axon

Back 61

refractory period

Front 62

necessary as it alls the proteins of voltage sensitive ion channels to restore to their original polarity

Back 62

refractory period

Front 63

will not elicit an action potential

Back 63

sub-threshold

Front 64

stimuli that are just string enough to depolarize the membrane to the threshold potential and elicit an action potential

Back 64

threshold stimuli

Front 65

sodium channels begins to close and the potassium channels open more than normal

Back 65

repolarization stage

Front 66

will not elicit an action potential

Back 66

sub-threshold

Front 67

the excited membrane does not repolarize immediately after depolarization instead, the potential remains on a plateau near the peak of the spike potential for many milliseconds, and only the repolarization begin

Back 67

plateau

Front 68

the excited membrane does not repolarize immediately after depolarization instead, the potential remains on a plateau near the peak of the spike potential for many milliseconds, and only the repolarization begin

Back 68

plateau

Front 69

refractory period which typically lasts about 1ms

Back 69

absolute refractory period

Front 70

occur only when the initial stimulus is sufficient to elecvate the membrane potetial beyond the threshold potential

Back 70

all-or none principle

Front 71

action potentials are initiated in the ___

Back 71

axon hillock

Front 72

refractory period which typically lasts about 3ms

Back 72

relative refractory period

Front 73

means that, although the action potential affects all other ion channels nearby, the upstream ion channels cannot open again since they are in their refractory period, so only the downstream channels open causing the action potential to move one-way along the axon

Back 73

refractory period

Front 74

action potentials are initiated in the ___

Back 74

axon hillock

Front 75

stimuli that are just string enough to depolarize the membrane to the threshold potential and elicit an action potential

Back 75

threshold stimuli

Front 76

sodium channels begins to close and the potassium channels open more than normal

Back 76

repolarization stage

Front 77

necessary as it alls the proteins of voltage sensitive ion channels to restore to their original polarity

Back 77

refractory period

Front 78

will not elicit an action potential

Back 78

sub-threshold

Front 79

means that, although the action potential affects all other ion channels nearby, the upstream ion channels cannot open again since they are in their refractory period, so only the downstream channels open causing the action potential to move one-way along the axon

Back 79

refractory period

Front 80

occur only when the initial stimulus is sufficient to elecvate the membrane potetial beyond the threshold potential

Back 80

all-or none principle

Front 81

refractory period which typically lasts about 1ms

Back 81

absolute refractory period

Front 82

the excited membrane does not repolarize immediately after depolarization instead, the potential remains on a plateau near the peak of the spike potential for many milliseconds, and only the repolarization begin

Back 82

plateau

Front 83

necessary as it alls the proteins of voltage sensitive ion channels to restore to their original polarity

Back 83

refractory period

Front 84

stimuli that are just string enough to depolarize the membrane to the threshold potential and elicit an action potential

Back 84

threshold stimuli

Front 85

refractory period which typically lasts about 3ms

Back 85

relative refractory period

Front 86

refractory period which typically lasts about 1ms

Back 86

absolute refractory period

Front 87

action potentials are initiated in the ___

Back 87

axon hillock

Front 88

will not elicit an action potential

Back 88

sub-threshold

Front 89

means that, although the action potential affects all other ion channels nearby, the upstream ion channels cannot open again since they are in their refractory period, so only the downstream channels open causing the action potential to move one-way along the axon

Back 89

refractory period

Front 90

refractory period which typically lasts about 3ms

Back 90

relative refractory period

Front 91

the excited membrane does not repolarize immediately after depolarization instead, the potential remains on a plateau near the peak of the spike potential for many milliseconds, and only the repolarization begin

Back 91

plateau

Front 92

action potentials are initiated in the ___

Back 92

axon hillock

Front 93

necessary as it alls the proteins of voltage sensitive ion channels to restore to their original polarity

Back 93

refractory period

Front 94

means that, although the action potential affects all other ion channels nearby, the upstream ion channels cannot open again since they are in their refractory period, so only the downstream channels open causing the action potential to move one-way along the axon

Back 94

refractory period

Front 95

refractory period which typically lasts about 1ms

Back 95

absolute refractory period

Front 96

necessary as it alls the proteins of voltage sensitive ion channels to restore to their original polarity

Back 96

refractory period

Front 97

refractory period which typically lasts about 3ms

Back 97

relative refractory period

Front 98

refractory period which typically lasts about 1ms

Back 98

absolute refractory period

Front 99

refractory period which typically lasts about 3ms

Back 99

relative refractory period

Front 100

action potential jumps from node to node

Back 100

saltatory conduction