Quiz 5

Question 1

Graded potentials

Answer 1

passive (electrotonic)
degrade with distance and time
variable amplitude/duration
positive or negative sign
sub-threshold: no AP
can summate to reach threshold

Question 2

Action Potentials

Answer 2

Active
no decrement with distance (maintains same amplitude)
All-or-none: fixed duration
Supra-threshold
cannot summate

Question 3

Common features between graded and action potentials

Answer 3

voltage changes in membrane
propagate down neuron- process: axon/dendrite
transient events

Question 4

axon terminal

Answer 4

output structure of one neuron

Question 5

dendrite

Answer 5

input structure of another neuron

Question 6

ligand-gated ion channel=

Answer 6

iontropic channel

Question 7

depolarization

Answer 7

membrane more positive to rest (Excitatory Post Synaptic Potential- EPSP)
increases likelihood of firing an AP
Na could yield EPSP

Question 8

hyperpolarization

Answer 8

membrane more negative to rest (inhibitory post synaptic potential- IPSP)
moves further from firing an AP
K/Cl could yield IPSP

Question 9

If neurotransmitter opens a receptor and increases Na permeability, then…

Answer 9

NA flows in, Vm would become more positive, towards Ena

Question 10

If neurotransmitter opens a receptor and increases K permeability, then…

Answer 10

K flows out, Vm becomes more negative, toward Ek

Question 11

Passive

Answer 11

decreases in strength as they spread away from point of origin

Question 12

Graded potentials are passive…

Answer 12

they decrease in amplitude with distance and time

Question 13

Temporal Summation

Answer 13

summation over short time, getting us to threshold for an AP

Question 14

Spatial Summation

Answer 14

2+ roughly simultaneous PSPs from different locations sum up across space

Question 15

ligand

Answer 15

something that can bind

Question 16

Voltage Na channels open ___ in response to depolarization, causing

Answer 16

fast
Na+ ions to rapidly flow in

Question 17

K channels open ____ in response to depolarization, causing

Answer 17

slow
K ions to flow out

Question 18

activation

Answer 18

opening of a channel
depolarization to open, hyperpolarization to close

Question 19

De-activation

Answer 19

closing of a channel

Question 20

Inactivated

Answer 20

open channel but it is blocked

Question 21

Na+ channels are blocked

Answer 21

potentials must be slightly depolarized
blocking needs time (delayed)
nothing can flow through when blocked

Question 22

Step 1 of AP

Answer 22

resting membrane potential

Question 23

Step 2 of AP

Answer 23

depolarizing stimulus

Question 24

Step 3 of AP

Answer 24

membrane depolarizes to threshold; NA channels open fast and K channels open slow

Question 25

Step 4 of AP

Answer 25

rapid Na entry depolarizes cell

Question 26

Step 5 of AP

Answer 26

Na channels block and K channels open

Question 27

Step 6 of AP

Answer 27

K flows out of cell into ECM

Question 28

Step 7 of AP

Answer 28

K channels remain open, addition K ions leave cell, hyperpolarizing the cell, Na channels close

Question 29

Step 8 of AP

Answer 29

K channels close, less K ions leak out of cell

Question 30

Step 9 of AP

Answer 30

Cell returns to resting ion and membrane permeability

Question 31

Na opening of Na channels is ____ feedback and is stopped by _____

Answer 31

positive
blocking

Question 32

threshold

Answer 32

state of being where one channel type behavior outstrips the other
Na permeability briefly outstrips K permeability

Question 33

refractory period

Answer 33

unwilling/unable to fire action potential
because Na channels are blocked

Question 34

Myelination

Answer 34

provides insulation with little gaps (nodes) and isolation from other axons

Question 35

Na/K channels are located in ___ and not under ____ this allows for____

Answer 35

nodes
myelin
saltatory conduction

Question 36

saltatory conduction

Answer 36

potential jumps from node to node, allowing quicker propagation

Question 37

propagation

Answer 37

local current flow

Question 38

Synapse

Answer 38

point of connection between two neurons
basic mechanism of communication between neurons or to effector

Question 39

Electrical synapse

Answer 39

result of gap junctions
bi-directional signaling
direct electrical coupling
second cell mirrors first cell

Question 40

Chemical synapse

Answer 40

synaptic cleft= gap between neurons
anterograde (forward direction)
signals pre to post-synaptic
axon terminal contains mitochondria, ER, and vesicles
vesicles loaded with NT that bind to membrane and release into synaptic cleft