Neurophysiology part 1 stack 2

Question 1

What does a voltmeter measure?

Answer 1

The potential (charge) difference across the membrane of a resting cell

Question 2

The resting membrane potential of a resting neuron is approx. ___?

Answer 2

-70 mV

Question 3

What side of the membrane is negatively charged relative to the outside?

Answer 3

The cytoplasmic side of the membrane

Question 4

The membrane is said to be ____? Meaning?

Answer 4

Polarized, meaning it has a + electrical charge on one side and a - charge on the other

Question 5

The actual voltage diff. varies from ___mV to ___ mV?

Answer 5

-40 mV to -90 mV

Question 6

The potential is generated by what two differences?

Answer 6

1. The differences in ionic composition of ICF (intracellular fluid) and ECF (extracellular fluid)

And

2. The differences in plasma membrane permeability

Question 7

Extracellular fluid has ___ concentration of Na+ than _____ regarding diff. in ionic composition?

Answer 7

higher concentration than intracellular fluid which is balanced chiefly by Cl- ions

Question 8

Intracellular fluid has ____ concentration of what type of ion than extracellular fluid

Answer 8

higher concentration of K+ ions which is balanced by negatively charged proteins

Question 9

What ion plays the most important role in membrane potential?

Answer 9

Potassium ion

Question 10

What two factors does generating a resting membrane potential depend on?

Answer 10

1. On the diff. in K+ & Na+ concentration inside and outside cells

And

2. Diff. in permeability of the plasma membrane to K+ and Na+ ions

Question 11

The plasma membrane is impermeable to what and slight permeable to what ion?

Answer 11

Impermeable to large anionic proteins and slight permeable to Na+ ion through leakage channels

Question 12

The plasma membrane is how many times more permeable to what ion than sodium through leakage channels?

Answer 12

25 times more permeable to a potassium ion

Question 13

The inside of the cell is more negative as a result of what effect?

Answer 13

More potassium being able to diffuse out than sodium diffusing in which helps to est. a resting membrane potential

Question 14

The function of the Na+/K+ ATPase pump is ?

Answer 14

Stabilizes resting membrane potential by maintaining the ions concentration gradients

Question 15

In the Na+/K+ ATPase pump, how many sodiums are pumped out and potassium pumped back in?

Answer 15

3 Na+ are pumped out and 2 K+ are pumped in

Question 16

What two factors influence the membrane potential to change?

Answer 16

1. When concentrations of ions across membrane change

And

2. Membrane permeability to ions change

Question 17

Changes to membrane potential produce a ____ potential signal?

Answer 17

Graded potential signal where incoming signals operate over short distance

Question 18

Change to membrane potential produces a second signal that is an ___ potential?

Answer 18

Action, a long distance signals of axons

Question 19

Depolarization & hyperpolarization are terms describing ____?

Answer 19

Membrane potential changes relative to resting membrane potential

Question 20

With depolarization, what occurs?

Answer 20

A decrease in membrane potential, moving towards zero and above

Question 21

Depolarization causes the inside of the membrane to become ___ than the resting membrane potential?

Answer 21

less negative (more +)

Question 22

The probability of producing impulse increases or decreases with depolarization?

Answer 22

Increases

Question 23

With hyperpolarization what occurs to the membrane potential?

Answer 23

Increases, away from zero

Question 24

The inside of the membrane becomes more ____ than resting membrane with hyperpolarization?

Answer 24

negative

Question 25

With hyperpolarization, the probability of producing impulse ___?

Answer 25

decreases

Question 26

What are graded potentials?

Answer 26

Short-lived, localized changes in membrane potentials with more voltage changes and farther current flows the strong the stimulus

Question 27

Graded potentials are triggered by a ____ that ____?

Answer 27

stimulus that opens gated ion channels

Question 28

What are the two types of graded potentials?

Answer 28

1. Receptor potential (generator potential) And 2. Postsynaptic potential

Question 29

Where are graded potentials located in receptor potential?

Answer 29

In receptors of sensory neurons

Question 30

Postsynaptic potential involve what the graded potential of what?

Answer 30

neuron

Question 31

What occurs once a gated ion channel opens?

Answer 31

Depolarization spreads from one area of a membrane to the next

Question 32

How does depolarization spread?

Answer 32

As a result of opposite charges attracting each other, creating local currents that depolarize adjacent membrane areas, spreading the wave of depolarization

Question 33

Why does membrane potential decay with distance?

Answer 33

The current is lost through "leaky" plasma membrane and the voltage declines with distance from the stimulus (voltage is decremental)

Question 34

Graded potentials are short-____ ____?

Answer 34

lived, localized changes In membrane potential

Question 35

The stronger the stimulus, the more ____? in graded potentials

Answer 35

voltage changes and the farther current flows

Question 36

What is the principal way neurons send signals?

Answer 36

By means of long distance neural communication

Question 37

AP occur only in what?

Answer 37

muscle cells and axons of neurons

Question 38

Do APs decay over distance like graded potentials do?

Answer 38

No

Question 39

In neurons, APs are referred to as ___?

Answer 39

nerve impulse

Question 40

Action potentials involves the opening of ___?

Answer 40

specific voltage gated channels