A.d.a.m Exam 5

Front 1

what part of a neuron
receive(s) signals?

Back 1

dendrites

Front 2

whici part(s) of a neuron integrate(s) signals?

Back 2

cell body

Front 3

which part of a neuron transmits signals to next cell?

Back 3

axon

Front 4

where are action potentials generated in neurons?

Back 4

axon hillock

Front 5

what's the name of the cells that wrap around and electrically insulate axons in the PNS

Back 5

schwann cells

Front 6

what is this electrical insulation called

Back 6

myelin sheath

Front 7

what are the gaps in insulation called?

Back 7

nodes of ranvier

Front 8

is the concentration of sodium higher inside or outside the cell

Back 8

outside

Front 9

the concentration of potassium higher inside of outside the cell

Back 9

inside

Front 10

how do ions pass through cell membranes

Back 10

though ion channels

Front 11

what makes a cell permeable to a specific ion

Back 11

channels for a particular ion

Front 12

what ion are most cells in the body selectively permeable to

Back 12

potassium (k)

Front 13

what determines how permeable a membrane is to a specific ion

Back 13

# of channels

Front 14

how can you increase the permeability of a cell to an ion

Back 14

increasing the number of channels for a given ion

Front 15

what does adding open K+ channels do to the K+ permeability of the membrane?

Back 15

increase

Front 16

What does closed K+ channels do to the K+ permeability of the membrane?

Back 16

no change

Front 17

what does added open Na+ channels do to the K+ permeablity of the membrane?

Back 17

no change

Front 18

what does the nervous system use to produce fast changes in the membrane permeability to specific ions

Back 18

gated channels

Front 19

what controls the movement of ions through the cell membrane of a nueron

Back 19

ion channels

Front 20

what does "ion channels are selective mean"

Back 20

ions has to have certain characteristics

Front 21

are all ion channels open all of the time?

Back 21

no

Front 22

where are chemically gated channels located?

Back 22

on the dendrites and the cell body

Front 23

chemically gated channels are located on the dendrites and the cell body

why does this location makes sense:

Back 23

because the dendrites get messages from chemically gated channels

Front 24

where are voltage gated channels located:

Back 24

axon hillock

Front 25

what are chemically gated channels responsible for generating

Back 25

synaptic potentials

Front 26

what are voltage gated ion channels responsible for

Back 26

the generation and propagation of the action potential

Front 27

what causes an action potential

Back 27

voltage gated channels

Front 28

where is an action potential generated

Back 28

axon hillock

Front 29

"local signals from the dendrites and cell body"

means what

Back 29

ESP and ISP

Front 30

what happens to sodium channels when the axon hillock is depolarized

Back 30

they open fast

Front 31

do all depolarizations of the axon hillock produce action potentials?

Back 31

no

Front 32

which depolarizations do produce action potentials

Back 32

if a stimuli reaches the threshold

Front 33

can action potentials have different amplitudes

Back 33

no

Front 34

can action potentials have different durations

Back 34

no

Front 35

whats happens at a threshold

Back 35

a positive feedback look is established

Front 36

what happens to sodium movement at threshold

Back 36

more sodium flows into the cell

Front 37

what does the change in sodium movement do to the membrane potential

Back 37

causes cell to depolarize

Front 38

what causes the depolarization (rising phase) of the action potential?

Back 38

positive feed back loop

Front 39

extra credit


list the steps of an action potential

Back 39

1. sodium channels open, sodium begins to enter cell

2. potassium channels open, potassium beings to leave the cell

3. sodium channels become refractory, no more sodium enters the cell

4. potassium continues to leave the cell, causing the membrane potential to return to resting level

5. potassium channels close, sodium channels rest

6. extra potassium outside diffuses away

Front 40

what two things happen to stop the depolarization phase of the action potential

Back 40

1. sodium channels become inactivated
2. potassium channels open

Front 41

at resting membrane potential, are the voltage sensitive gates of sodium channels open or closed

Back 41

closed

Front 42

at resting membrane potential, are the inactivation gates of sodium channels open or closed

Back 42

open

Front 43

what happens to voltage sensitive gates of sodium channels when the membrane is depolarized to threshold

Back 43

open

Front 44

what happens to inactivation gates of sodium channels when the membrane is depolarized to threshold

Back 44

close

Front 45

what happens to the sodium channel a set time after it opens

Back 45

time sensitive stops the movement

Front 46

when during the action potential do voltage gated potassium channels open

Back 46

when action potential reaches its peak

Front 47

what causes repolarization of the membrane during the second half of the action potential?

Back 47

less sodium moves into cell, more potassium moves out of the cell - membrane potential becomes more negative moving toward resting value

Front 48

what causes the hyperpolarization at the end of the action potential

Back 48

potassium channels remain open after the cell repolarizes, cuasing membrane potential to become more negative than resting membrane potential

Front 49

where does sodium permeability increase rapidly during the action potential

Back 49

rising phase

Front 50

what causes the increase of sodium permeability?

Back 50

opening of voltage gated channels

Front 51

when does sodium permeablity decrease rapidly during the action potential

Back 51

during repolarization

Front 52

what causes the decrease in sodium permeability

Back 52

closing of channels

Front 53

when is potassium permeablity slowly decreasing during the action potential

Back 53

repolarization

Front 54

what causes the hyperpolarization of the action potential

Back 54

the potassium channels remain open after repolarization

Front 55

are the voltage gates of sodium channels mostly open or closed at rest

Back 55

closed

Front 56

at the inactivation gates of sodium channels mostly open or closed at rest

Back 56

open

Front 57

are the voltage gates of potassium channels mostly open or closed at rest

Back 57

closed

Front 58

what is the state of MOST potassium chanels during the relative refractory period

Back 58

open

Front 59

last question she asked..

something about speeds up

Back 59

diameter and how well its insulated

Front 60

what part of a neuron contains the nucleus

Back 60

cell body

Front 61

the cerebral hemispheres are connected internally by this:

Back 61

corpus collosum

Front 62

what is the satiety center (hunger)

Back 62

hypothalamus

Front 63

cavities within the brain

Back 63

ventricles

Front 64

relay center for conducting information from the spinal cord and cerebrum

Back 64

thalamus

Front 65

what is the brain stem made up of

Back 65

pons, midbrain, medulla oblongota

Front 66

what ion is linked with the depolarizing phase:

Back 66

sodium