neurophysiology

Question 1

What is diffusion?

Answer 1

ions flowing from high concentration to low concentration, a long concentration gradient.

Question 2

What is electrostatic pressure?

Answer 2

negatively charged ions repel, oppositely, charged ions attract.

Question 3

Semi permeable membrane explanation.

Answer 3

Screen door keeps mosquitoes out but let’s air get through.

Question 4

What are neurons just like?

Answer 4

Batteries – the store charge to use when needed.

Question 5

What if there is no charge in a neuron?

Answer 5

It’s dead.

Question 6

What charge is it outside axon?

Answer 6

Positive

Question 7

What charge is the inside axon?

Answer 7

Negative

Question 8

What is voltage?

Answer 8

Difference in potential

Question 9

Cell membrane is a what?

Answer 9

Lipid bilayer.

Question 10

What are the ion channels?

Answer 10

Protein spinning the membrane so ions can pass in and out

Question 11

What is important about the ion channels?

Answer 11

It doesn’t open to everybody.

Question 12

What are the gated channels?

Answer 12

Open/close in response to voltage changes, chemicals(drugs) and mechanical actions

Question 13

What can pass through the ion channels?

Answer 13

Sodium potassium chloride and calcium.

Question 14

Why can’t proteins leave the cell?

Answer 14

They are too fat and the membraned are too small– proteins are negatively charged

Question 15

What does the neuronal cell membrane do to water?

Answer 15

Repels water, so membranes need ion channels

Question 16

Since ions are surrounded by water, what must they do?

Answer 16

They can enter a cell only through a channel

Question 17

Why does potassium enter the cell?

Answer 17

Attracted to the negatively charged proteins.

Question 18

What can move in and out of the cell freely?

Answer 18

Potassium

Question 19

What happens if there is proteins in the bloodstream?

Answer 19

the cell is damaged

Question 20

When does potassium reach equilibrium?

Answer 20

When ion movement out is balanced by ion movement in.

Question 21

What happens when there’s too much potassium in the cell?

Answer 21

Other potassium ions, lose interest and leave

Question 22

What is the resting membrane equilibrium?

Answer 22

-60

Question 23

If they suck in what is the membrane slightly permeable to?

Answer 23

Sodium ions

Question 24

Why do sodium ions want in?

Answer 24

They are positive.

Question 25

What does the sodium potassium pump do?

Answer 25

pumps out 3 sodium and pumps in 2 potassium to maintain resting potential

Question 26

How is the sodium potassium pump powered

Answer 26

ATP

Question 27

What charge makes the cell useless

Answer 27

0

Question 28

What does tetrodotoxin block nerve action?

Answer 28

Binding to/blocking pores of voltage gated sodium channels in neuron membranes

Question 29

where is sodium

Answer 29

outside

Question 30

where is potassium

Answer 30

inside

Question 31

where is chlorine

Answer 31

outside

Question 32

where is calcium

Answer 32

outside

Question 33

where are proteins

Answer 33

inside

Question 34

what do tetrodotoxins do

Answer 34

blocks nerve action by binding to/blocking pores of voltage gated, sodium channels in neuron mems

Question 35

What does sodium do to the neuron?

Answer 35

Makes the neuron fire.

Question 36

what is the job of a neuron

Answer 36

take info to pt A to pt B

Question 37

WHat receives the info

Answer 37

dendrites

Question 38

Where does the action potential spark?

Answer 38

Axon hillock

Question 39

Where does the graded potential occur?

Answer 39

The dendrites

Question 40

What happens as you inject negative ions?

Answer 40

Becomes more than negative inside.

Question 41

What happens as graded potential spread across membranes?

Answer 41

They diminish like a ripples in a pond

Question 42

What number is the threshold?

Answer 42

-40

Question 43

What can graded potentials transform into?

Answer 43

Action potentials

Question 44

What happens when the membrane reaches threshold?

Answer 44

It triggers an action potential, inside the cell becomes briefly positive

Question 45

What happens once it hits -40?

Answer 45

The neuron jumps to +40.

Question 46

How can the cell be positive with negative components in the cell?

Answer 46

-40 voltage opens up so sodium rushes into the cell and then door slam shut

Question 47

What speed is an action potential?

Answer 47

One speed -> all or nothing

Question 48

What starts an action potential?

Answer 48

Incoming positive charge coming from the dendrites to axon hillock

Question 49

What happens in response to the initial depolarization?

Answer 49

Voltage gated sodium channels open.

Question 50

What happens as soon as the cell reaches the threshold?

Answer 50

voltage gated sodium ions flood into cell until membrane potential hits +40

Question 51

What happens after membrane potential hits +40?

Answer 51

Voltage gated sodium channels close and voltage gated potassium channels open

Question 52

What happens after vg potassium channels open

Answer 52

repolarization as K+ moves out and resting potential is restored

Question 53

When does sodium potassium pump come in during AP

Answer 53

during repolarization (3 Na+ out and 2 K+ in)

Question 54

how is the concentration gradient like at peak (action potential)

Answer 54

gradient pushing Na+ out is equals charge pushing Na+ in

Question 55

where does information enter nerve cell

Answer 55

at the synaptic site on the dendrite

Question 56

What is the absolute refractory phase

Answer 56

no more action potentials can be made

Question 57

What is the relative refractory phase

Answer 57

only a strong stimuli can cause another AP

Question 58

Why can't there be another action potential during the AR phase

Answer 58

the activation gate locks

Question 59

what does sodium do to neurons(think of putting salt on worms)

Answer 59

it causes neuron to fire

Question 60

how many action potentials are there in one axon

Answer 60

many

Question 61

why do action potentials travel in one direction

Answer 61

the refractory state of the membrane

Question 62

what does myelin do

Answer 62

speeds up the process

Question 63

what is periodic paralysis

Answer 63

genetic defect in Na+ channels - so neuron doesn't fire the way it needs to

Question 64

what happens after the action potential travels down to the axon terminal

Answer 64

voltage gated calcium channels open

Question 65

When do APs stop

Answer 65

no more voltage gates

Question 66

What does Calcium do

Answer 66

gives enzymes that make it active-controls everything

Question 67

What happens after Calcium enters

Answer 67

synaptic vesicles fuse with membrane and release transmitter into the cleft

Question 68

What happens after the fusion

Answer 68

transmitters bind to postsynaptic receptors- EPSP or IPSP

Question 69

what may transmitters bind to instead

Answer 69

presynaptic autoreceptors, decreasing release

Question 70

what are neurotransmitters inactivated by

Answer 70

degradation or reuptake

Question 71

what is Excitatory postsynaptic potential

Answer 71

makes cell more likely to fire because it is more positive

Question 72

what is inhibitory postsynaptic potential

Answer 72

makes the cell less likely to fire because it is more negative

Question 73

how are epsp and ipsps decided

Answer 73

the axon hillock

Question 74

what is a reuptake

Answer 74

reabsorptions of a neurotransmitter

Question 75

what is a degradation

Answer 75

breakdown/inactivation of transmitter by an enzyme

Question 76

What is an electrical synapses

Answer 76

ions flow DIRECTLY through large channels into neuron w out delay

Question 77

What are the benefits an electrical synapses

Answer 77

faster, allow neurons to synchronize saves energy

Question 78

what happens when neurons fire at the same time

Answer 78

a seizure

Question 79

what are ligands

Answer 79

receptors to activate or block(lock and key)

Question 80

endogenous ligands

Answer 80

neurotransmitters and hormones

Question 81

exogenous ligands

Answer 81

drugs and toxins from outside the body

Question 82

the number of receptors in a neuron what

Answer 82

varies over time

Question 83

what is up-regulation

Answer 83

sensitization-increase number of receptors-more of a response over time

Question 84

what is a down-regulation

Answer 84

tolerance- decrease in receptors-less of an effect over time

Question 85

what is electroencephalogram(EEG)

Answer 85

recording of brain activity- used for seizures