action potential

Question 1

physiology behind unique characterisics of nervous system

Answer 1

1. rapid and specific propagation of signa
2. integration, computation
3. adaptation

Question 2

what are neurons named based off of

Answer 2

1. shape
2. anatomical feature (where in body)
3. neurotransmitter
4. function

Question 3

input zone of neurons

Answer 3

dendrites

Question 4

integration zone of neurons

Answer 4

cell body

Question 5

point of action potential initiation

Answer 5

axon hillock (trigger zone)

Question 6

conducting zone

Answer 6

axon

Question 7

output zone

Answer 7

axon terminal

Question 8

sensory and motor neuron length

Answer 8

excede a meter

Question 9

resting membrane potential

Answer 9

-50 to -70

Question 10

megnitude of membrane potential

Answer 10

depends on degree of sepeartion of opposite charges

less potential- depolarized (less neg inside)

more potential- hyperpolarized (more neg inside)

Question 11

molecules that can go thorugh the lipid bilayer

Answer 11

hydrophobic molecule- o2, co2, steroid
small (uncharged polar)- h20, glycerol, ethanol

Question 12

molecules that can go thorugh the lipid bilayer

Answer 12

hydrophobic molecule- o2, co2, steroid
small (uncharged polar)- h20, glycerol, ethanols

Question 13

is the lipid bilayer a good insulator

Answer 13

yes

Question 14

what occurs during depolarization

Answer 14

Na and Ca into cell

Question 15

what occurs during hyperplarization

Answer 15

K out and Cl in

Question 16

what forms water filled pores

Answer 16

ion channels

Question 17

what are the conducting and non conducting states of ion channels change called

Answer 17

gating

Question 18

what do channel gates respond to

Answer 18

changes in membrane potential
ligand binding
mechanical forces

Question 19

what ion channels are present in the cell body and dendrites and function

Answer 19

various not just na and k

synaptic potential and intrinsic excitability

Question 20

are ion channels evenly distribbuted in a neuron

Answer 20

no

Question 21

how does the sodlum gated cahnnel work

Answer 21

there is an activation gate and an incativation gate. the activation gate is closed at first and at threshold it opens rapidly and lets na in. then slow closing of inactivation gate happens and the state is inactivated and then it becomes closed state when the activation gate closes again. inactivated channels cannot reopen. fast activating and fast inactivating

Question 22

how does the potassium gated channel work

Answer 22

it has a closed and activated state and the openng at the threshold is delayed not rapid like sodium channel. its persistant

Question 23

threshold

Answer 23

start of action potential, point of no return

Question 24

what underlies the all or none nature of action potential

Answer 24

the fact that once threshold is reached, the positive feedback of Na channels activation begins and cannot be stopped (point of no return)

Question 25

what leads to potential reaching 0 mv

Answer 25

explosive depolarixation

Question 26

what happens when the action potentail reaches its peak

Answer 26

na inactivation gate begins to close and k gate opens

Question 27

what does membrane repolarixation lead to

Answer 27

na and k channels to return to closed state. both are available to open at next stimulation

Question 28

what does afterhyperpolarixation (ahp) do

Answer 28

makes it harder to elicit an action potential because the membrane is more hyperpolarized

Question 29

what is afterhyperpolarization

Answer 29

the little extra dip in membrane potential

Question 30

strong vs weak signals in all or none

Answer 30

high frequency

Question 31

different patterns in neuron firing

Answer 31

various ion channles that can induce various firing patterns

Question 32

how do action potential s not wane in size as potential propogates down the azon

Answer 32

bc it is regenerative

Question 33

what does the refractory period cause

Answer 33

prevents backward propagation of AP and limits action potential frequency

Question 34

conduction velocity is defined by

Answer 34

axon diameter dnesity of na channels myelin insulation distance between the nodes of ranvier

Question 35

saltatory conduction

Answer 35

the jumping of action potentials from one node of ranvier to the next due to myelination of axon

Question 36

what provides myelin

Answer 36

glial cells

Question 37

glial cells in CNS and PNS

Answer 37

CNS- oligodendrocyte PNS- schwann cell

Question 38

what does myelin consist of

Answer 38

tightly wrapped cell membrane

Question 39

myelin purpose

Answer 39

lessens the amount of leak across the membrane. myelin does NOT conduct current

Question 40

chronic pain axon type

Answer 40

unmyelinated thin axon

Question 41

Aa nerve fibre

Answer 41

proprioception (awareness of movement of body) contraction of skeletal muscle (ALPHA MOTOR NEURON)

Question 42

AB nerve fibre

Answer 42

touch

Question 43

Ag nerve fibre

Answer 43

acute pain (sudden and sharp)

Question 44

C nerve fibre

Answer 44

chronic or dull pain, temperature, itch

Question 45

role of nodes of ranvier

Answer 45

regeneration and propagation of action potential

Question 46

rise and decay

Answer 46

rise- influx of na decay- k efflux

Question 47

where is the highest density of na channels

Answer 47

axon hillock