Passive Membrane Properties

Question 1

Neurons produce a non-propagated local potential called a(n) _____, due to a local change in _____.

Answer 1

electrotonic potential
ionic conductance
(e.g. channel opening due to synaptic response).

Question 2

When a electrotonic potential spreads along a stretch of membrane, it becomes _____.

Answer 2

exponentially smaller

Question 3

Electrotonic refers to the “_____” spread of charge inside a neuron.

Answer 3

passive

“Passive” means that voltage-dependent changes in membrane conductance do not contribute.

Question 4

Neurons produce a propagated impulse called a(n) _____.

Answer 4

action potential

Question 5

The electrotonic potential travels via _____.

Answer 5

electrotonic spread

Question 6

Electrotonic potentials from multiple sources can sum _____ or _____.

Answer 6

spatially

temporally

Question 7

electrotonic spread is a(n) _____ response.

Answer 7

graded

Question 8

Electrotonic spread and summation of many inputs is responsible for increasing the _____ of the soma to _____ and trigger the_____.

Answer 8

voltage
exceed threshold
action potential

Question 9

Electrotonic potentials are conducted _____ than

action potentials, but _____ rapidly, thus they are unsuitable for _____.

Answer 9

faster
attenuate
long-distance signaling

Question 10

The action potential is a(n) _____ propagation down the _____ of the neuron during which the current is _____.

Answer 10

all-or-none
axon
regenerated

Question 11

Input resistance _____ in outward or inward current pulses and produces _____ and _____
changes in membrane potential.

Answer 11

increases
proportional
symmetrical

Question 12

An I-V curve is obtained by plotting the _____ against the _____.

Answer 12

steady state voltage

injected current

Question 13

The slope of the I-V curve defines the _____ of the neuron.

Answer 13

input resistance

Question 14

The input resistance of the cell determines how much the cell will _____ in response
to a steady current.

Answer 14

depolarize

Question 15

The magnitude of a cell’s depolarization is given by _____.

Voltage is equal to the product of _____ and _____.

Answer 15

Ohm’s law
V = I * R

current
resistance

Question 16

In a neuron, the input resistance depends on both the _____ and the _____.

Answer 16

density of the resting ion channels in the membrane
(i.e. the number of open channels per unit area of membrane)
size of the cell

Question 17

The larger the neuron, the _____ its

membrane surface area will be and the _____ the input resistance.

Answer 17

greater
lower
(since there will be more
resting channels to conduct ions)

Question 18

capacitance (unit = _____) is the ability

of a body to _____.

Answer 18

farad

hold an electrical charge

Question 19

a capacitor is a device that stores energy in the _____ created between _____ on which _____ electric charges have been placed.

Answer 19

electric field
a pair of conductors
equal but opposite

Question 20

A capacitor consists of two _____ separated by a(n) _____.

Answer 20

conductors (plates)

insulator (dielectric)

Question 21

In a parallel plate capacitor, capacitance is directly proportional to _____ and inversely proportional to _____.

Answer 21

the surface area of the conductor plates
the separation distance between the plates

C = Q / V

Question 22

The action potential is a regenerative wave of _____.

Answer 22

Na+ permeability increase

Question 23

The length constant (_____) is a measure of the efficiency of the passive spread of _____ along the _____.

Answer 23

lambda
voltage changes
membrane (axon or dendrite)