transmission of neural impulses

Question 1

____________ is the net electric potential different that exists across the cell membrane, created by the movement of charged molecules across the membrane

Answer 1

resting membrane potential

Question 2

what is the average resting membrane potential for neurons?

Answer 2

-70 mV

Question 3

what are the two ions that maintain the resting potential?

Answer 3

potassium and sodium

Question 4

to maintain the resting potential, _________ is naturally drawn out of the cell and __________ is naturally drawn into the cell

Answer 4

K+ out
Na+ in

Question 5

the balance of the equilibrium potential of sodium and potassium is reached around -70 mV and is known as ___________

Answer 5

resting membrane potential

Question 6

given the continual ion leaking of the membrane, Na+ / K+ ATPase continually pumps _________ into the cell and _________ out of the cell

Answer 6

K+ pumped into the cell
Na+ pumped out of the cell

Question 7

excitatory input causes ___________ and raises the membrane potential

Answer 7

depolarization

Question 8

inhibitory input causes ___________ and lowers the membrane potential

Answer 8

hyperpolarization

Question 9

two types of summation?

Answer 9

1. temporal
2. spatial

Question 10

________ summation is when multiple signals are integrated during a relatively short period of time

Answer 10

temporal

*temporary = short period of time

Question 11

___________ summation si when the additive effects are based on the number and location of the incoming signals

Answer 11

spacial

*space = location

Question 12

during depolarization, there is an influx of __________ into the cell

Answer 12

sodium

Question 13

during repolarization, there is an influx of ___________ out of the cell

Answer 13

potassium

Question 14

sodium channels can exist in what three states?

Answer 14

1. closed - before cell reaches threshold
2. open - from -55 mV (threshold) to +35 mV
3. inactive - from +35 mV to -70 mV (resting potential)

Question 15

what is the purpsoe of hyperpolarization?

Answer 15

it makes the neuron refractory to further action potentials

Question 16

two types of refractory periods?

Answer 16

1. absolute refractory period
2. relative refractory period

Question 17

______________ refractory period is when no amount of stimulation can cause another action potential to occur

Answer 17

absolute refratory period

*absolutely will not work

Question 18

______________ refractory period is when there must be a greater than normal stimulation to cause an action potential

Answer 18

relative refractory period

Question 19

______________ is the movement of action potentials down the axon and initiates neurotrasmitter release

Answer 19

impulse propagation

Question 20

T / F - action potentials move in a wave like fashion until it reaches the nerve terminal

Answer 20

true

Question 21

(increased / decreased) length = slower conduction

Answer 21

increased (higher resistance)

Question 22

greater cross sectional areas = (slower / faster) conduction

Answer 22

faster (decreased resistance)

Question 23

what is saltatory conduction?

Answer 23

signal hops from node to node

Question 24

T / F - all action potentials within the same types of neuron have the same potential difference during depolarization

Answer 24

true

Question 25

does incresed intensity of a stimulus result in an increased potential difference of the action potential?

Answer 25

no

Question 26

if a neuron signals to a agland or muscle, rather than another neuron, the postsynaptic cleft is termed as a ________

Answer 26

effector

Question 27

prior to release, neurotransmitters are stored in _____________ in the nerve terminal

Answer 27

membrane boun vesicles

Question 28

when the action potential reaches the nerve temrinal, ______________ open

Answer 28

voltage gated clacium channels

Question 29

what happens to the postsynaptic cell if the receptor is a ligand gated channel?

Answer 29

it will be either depoalrized or hyperpolarized

Question 30

what happens to the postsynpatic cell if the receptor is a G protein coupled receptor?

Answer 30

cause changes in the levels cAMP or an influx of calcium

Question 31

T / F - there are almost no circustances under which constant signaling to the postsynaptic cell would be desireable

Answer 31

true

Question 32

what are the three ways neurotransmitters can be removed from the synpatic cleft?

Answer 32

1. broken down by enzymatic reactions
2. brought back to the presynpatic neuron using reuptake carriers
3. diffuse out of the synaptic cleft

Question 33

what is an example of a neurotransmitter that uses enzymatic reactions to get rid of neurotrasmitters?

Answer 33

acetylcholine (ACh) broken down by acetylcholinesterase

Question 34

what is an example of a neurotransmitter that uses reuptake carriers to get rid of neurotrasmitters?

Answer 34

serotonin (5-HT)
dopamine (DA)
norepinephrine (NE)

Question 35

what is an example of a neurotransmitter that uses diffusion to get rid of neurotrasmitters?

Answer 35

nitric oxide (NO)