Physiology - Neurophysiology

Front 1

major functions of nervous system (4)

Back 1

1. detecting info from the environment
2. integrating info form competing inputs
3. generating behavioral responses
4. remembering selected info for future reference

Front 2

two types of nerve signals

Back 2

graded responses or receptor potentials

action potentials or "all or non" nerve impulses

Front 3

graded responses or receptor potentials are used by what kind of neurons?

Back 3

graded responses are used by sensory neurons to accumulate info about the local environment.

Front 4

define action potential

Back 4

a transient depolarization of an excitable membrane

Front 5

what two cations move into the cell to depolarize the membrane?

Back 5

Na+ and Ca++

Front 6

what cation leave the cell to repolarize the membrane?

Back 6

K+

Front 7

Back 7

the increased width of cardiac AP is caused by?

Hint 7

The heart uses voltage-gated Ca+2 channels, which are activated by the initial Na+-induced depolarization. The simultaneous opening of Ca+2 and K channels creates the long shoulder on the cardiac AP.

Front 8

the absolute refractory phase (inactivation period) is due to inactivation of ____
Can another action potential be initiated?

Back 8

Na+ channel
No, another AP cannot be initiated

Front 9

the shape of AP depends on

Back 9

the array of ion channels present in the membrane

Front 10

define relative refractory period

Back 10

harder to initiate action potential because voltage-dependent K+ channels open, pulling Vm towards Ek.

Front 11

IFM region of ion channel

Back 11

inactivation "ball" - ball and loop

Front 12

S4 segment of ion channel

Back 12

voltage sensor on Na+ or K+ ion channel

Front 13

axonal hillock

Back 13

where AP originate, Na+ channels are concentrated here, needed to convert graded potential to AP

Front 14

graded potential

Back 14

amplitude is proportional to stimuli strength (0-10mV), passive electrical conduction, amplitude decreases with distance from initial site

Front 15

active potential

Back 15

amplitude is constant - all or none, >50mV
active spread to neighboring membrane
amplitude constant with distance form initial site

Front 16

2 ways that electrical signals are conducted along the nerves

Back 16

active and passive

Front 17

Influx of Ca2+ at the presynaptic terminal trigger.
the amount

Back 17

neurotransmitter release

Front 18

2 proteins important in targeting the vesicles to the plasma membrane at the site to neurotranmitter release.

Back 18

synapsin I and calmodulindependedent kinase II

Front 19

2 types of proteins transport the transmitter into the vesicle

Back 19

proton pump and a family of transmitter transporters

Front 20

2 neurotransmitters released in a wide area not a synpase.

Back 20

serotonin and dopamine

Front 21

neurotransmitter receptors can be ____ or _____

Back 21

ion channels (ionotropic receptor) or second messenger receptors (metabotropic receptor, G protein coupled)

Front 22

ionotropic receptors are ____ than metabotropic receptors

Back 22

faster

Front 23

neurotransmitters can be degraded in 3 ways

Back 23

1. degradation by enzymes (acetylcholinesterase)
2. transported back into presynaptic terminal for recycling.
3. diffusion of message away from the site of the post-synaptic receptors

Front 24

Long QT syndrome

Back 24

mutation in K+ channels, result in reduced conductance.
Repolarization weak, delayed. Distorts rhythm, new AP kicks in before membrane repolarized.

Front 25

primary erythermalgia pain

Back 25

Na+ channel mutation, making the channel more active. Patient are sensitive to pain. the channel is expressed in dorsal root ganglion nerve.

Front 26

EPSP (exitatory post synpatic potential) is about ___ mV

Back 26

-0.5mV

Front 27

inhibitory post-synaptic potential involves the influx of ___ of efflux of ___

Back 27

influx of Cl- or efflux of K+

Front 28

How is miniature excitatory post-synaptic potential or MEPSP generated?

Back 28

vesicles of neurotransmitter are spontaneous released from pre-synaptic terminal in the absence of a presynaptic signal

Front 29

in order to generate AP in the post-synaptic cell, what's the potential (mV) need to be? how many terminals are required in depolarization

Back 29

10-20mV
40-80 terminals are required

Front 30

presynaptic inhibition is ___ to __ synapse. neurotransmitters that are usually involved are ... (2)

Back 30

axon-to-axon synapse.
GABA or glycine are the usual inhibitory neurotransmitters.

Front 31

spatial summation

Back 31

inputs to the post-synaptic neuron are summed spatially (add together the effect of inhibitory and excitatory inputs)

Front 32

Define facilitation in neurophysiology, and what ion level is responsible for facilitation?

Back 32

an input path is activated by hasn't reached threshold, the nerve is facilitated.
Ca2+ level in the presynaptic terminals are responsible for facilitation.

Front 33

potentiation

Back 33

during tetanic stimulation of pre-synaptic neuron, the postsynaptic potential increases in size

Front 34

posttetanic potentiation

Back 34

after presynaptic neuron is returned to control rate of firing (after tetanic stimulation), postsynaptic potential continue to increase for sometime (min or hours).

Front 35

temporal summation

Back 35

when another stimulus arrives at the postsynaptic cells that are still undergoing depolarization. The stimulus adds to the depolarization of the last stimulus.

Front 36

synaptic fatigue

Back 36

over excitation lead to depletion of neurotransmitter resulting in a loss of excitability. Fatigue is due to loss of ionic gradients since Na+K+ pumps work slower than ion channels.

Front 37

adaption: 2 types in a sensory receptor. Define them.

Back 37

rapid: generator potentialThe generator potential of
a rapidly adapting receptor decreases rapidly to zero. Rapidly
adapting receptors respond only at the beginning and end of the
stimulus.
slow: The generator potential of a slowly adapting receptor has
an initial phase that adapts to a stable and maintained level of
stimulus energy.

Front 38

define synaptic efficacy. it is altered by?

Back 38

synaptic efficacy is the efficiency of coupling btw different neurons in a given pathway or network.
Efficacy
is altered by changes in pH (alkalosis increases excitability), hypoxia (loss of excitability) and drugs such as caffeine.

Front 39

biogenic amines

Back 39

catecholamine: dopamine, NE, Epi
Cholinergic: ACh
Indolamine: serotonin and histamine

Front 40

metabotropic receptors

Back 40

dopamine, seratonin, Epi and NE receptors, glutamate

Front 41

major excitatory and inhibitory neurotransmitters of brain

Back 41

excitatory: glutamate and aspartate
inhibitory: glycine and GABA

Front 42

neuropeptides

Back 42

substance P, somatostatin, neuropeptide Y, vasoactive intestinal polypeptide (VIP)

Front 43

opiates

Back 43

endorphin, enkephalin

Front 44

gaseous neurotransmitter

Back 44

Nitric oxide

Front 45

ionotropic receptors

Back 45

ACh receptor, seratonin receptor, glutamate receptor

Front 46

astrocytes
microglia
oligodendroctes

Back 46

Astrocytes – communicate between blood and neurons, can release transmitters into synaptic cleft
Microglia – immune cells of nervous system
Oligodendrocytes - myelin

Front 47

nissl bodies

Back 47

ribosomes, located in soma

Front 48

thin membrane: ____ capacitor, ____ charge stored, ____ time to charge before membrane potential set

Back 48

larger capacitor
more charge stored
longer time to charge before membrane potential set

Front 49

thicker membrane: ____ capacitor, ____charge stored, ____ to charge membrane

Back 49

smaller capacitor
less charge stored
quicker to charge membrane

Front 50

the speed of neuronal impulses is affected by... (3)

Back 50

temperature, axon diameter, myelin sheath

Front 51

schwann cells in periphery
oligodendroctes in CNS

Back 51

produce myelin sheath that wraps around axon

Front 52

multiple sclerosis

Back 52

result from auto-immune destruction of myelin, forms scars inpedes neural transmission.