Test 2

Question 1

Two things that dictate membrane potential

Answer 1

of channels per ion; # of ions

Question 2

Resistance

Answer 2

a channel is an impedance to an ion

Question 3

Membrane Capacitance

Answer 3

membrane stores a charge because the ions cannot pass through

Question 4

Internal Axial Resistance

Answer 4

as the amplitude spreads along the surface it decreases; why there is a graded potential; leak channels decrease the effect as time goes on

Question 5

why does the membrane capacitance take the form of a inverse exponent curve?

Answer 5

kind of clogs the channels up

Question 6

lambda gives?

Answer 6

how far from a stimulus site will a Vm be detectable

Question 7

soma

Answer 7

contains nucleus, mitochondria, ER

Question 8

dendrites

Answer 8

branch extensively; receive signals from other neurons

Question 9

axon

Answer 9

transmits singals to other neurons

Question 10

transport molecule

Answer 10

have central pores that open to 1 side of membrane at a time; undergoes comformational changes; SLOW

Question 11

ion channnels

Answer 11

increase the permeability of the PM to ions; opne to both sides of the membrane at a time; FAST

Question 12

neuroglia

Answer 12

provide supportive scaffolding for neurons; some produce chemicals that guide neuron connection; other insulate neuron processes

Question 13

neurons

Answer 13

excitable nerve cells; transmit electrical signals

Question 14

axon terminal

Answer 14

secretory region of neurotransmitters

Question 15

Why do nerve cells need to be maintained?

Answer 15

many diseases use retrograde transport to cause neuron malfunction

Question 16

depolarization

Answer 16

inside of cell becomes +

Question 17

hyperpolarization

Answer 17

inside of cell becomes more -

Question 18

repolarization

Answer 18

inside of cell back to -70mV

Question 19

EPSP

Answer 19

depolarization

Question 20

IPSP

Answer 20

hyperpolarization

Question 21

Why do graded potentials decrease with distance?

Answer 21

leak channels

Question 22

ion channels for graded potential

Answer 22

Cl- Na+ K+ (less frequent)

Question 23

why are graded potentials bidirectional?

Answer 23

the local currents that are created depolarize adjacent membrane areas and allow the wave of depolarization to spread

Question 24

Depolarization Phase

Answer 24

voltage gated Na+ channels open to allow in

Question 25

Repolarization Phase

Answer 25

Na+ channels close and K+ open to allow in

Question 26

Hyperpolarization Phase

Answer 26

K+ channels close and leak channels bring the cell back to -70mV

Question 27

Absolute Refractory Period

Answer 27

second AP cannot be generated; Na+gates are inactivated

Question 28

Relative Refractory Period

Answer 28

second action potential can be generated with a stronger stimulus; some Na+ gates closed, some inactivated

Question 29

consequences of refractory period

Answer 29

all-or-none principle; frequency coding; unidirectional propagation

Question 30

threshold

Answer 30

minimum depolarization necessary to induce the regenerative mechanism for the opening of Na+ channels