ELECTROPHYSIOLOGY

Question 1

makes the membrane impermeable to ions and water soluble materials

Answer 1

bilayer of lipids

Question 2

most abundant lipid in the plasma membrane

Answer 2

phospholipids

Question 3

major cation inside the cell

Answer 3

potassium

Question 4

major cation outside the cell

Answer 4

sodium

Question 5

major anion outside the cell

Answer 5

chloride

Question 6

major anion inside the cell

Answer 6

proteins

Question 7

amphiphatic (contains both hydrophilic and hydrophobic regions)

Answer 7

phospholipids

Question 8

non-polar, hydrophobic part of the phospholipid

Answer 8

fatty acid tails

Question 9

polar, hydrophilic and exposed to aqueous environment

Answer 9

phosphate head groups

Question 10

two types of transport processes

Answer 10

active and passive

Question 11

always open

contribute significantly to the resting membrane potential

plasma membrane has more K ion leakage than Na ion channel

increase K ion permeability

Answer 11

leak (non-gated ion channel)

Question 12

open and close because of some sort of stimulus

when the open they change the permeability of the cell membrane

Answer 12

regulated (gated) ion channel

Question 13

open or close in response to small voltage changes across the cell membrane

when cell is stimulated, that relative charge changes and voltage gated ion channels either open or closed

Answer 13

voltage gated ion channels

Question 14

regulated by ligands
example: acetylcholine attaches to a receptor

Answer 14

ligand gated ion channels

Question 15

the ligand molecule itself can open or close the channel by binding to a portion of the channel protein as in the case of acetylcholine

Answer 15

direct ligand gated channel

Question 16

ligand may act indirectly via a protein called G protein that activates another secondary messenger in the cytosol that in turn operates the gate

Answer 16

indirect ligand gated channel

Question 17

regulated by mechanical stimulus such as pressure or stretch

opens and closes in response to mechanical stimulation in the form of vibration, pressure, or tissue stretching

Answer 17

mechanically gated ion channels

Question 18

number of channels that are open in a membrane

channels open - increase
channels close - decrease

Answer 18

membrane conductance

Question 19

potential difference generated across a membrane that is being generated as a result of the differences of the concentration of an ion

Answer 19

diffusion potential

Question 20

diffusion potential wherein the electrical and chemical gradient for the certain ion is equal

net diffusion will be zero

Answer 20

equilibrium potential

Question 21

measured potential difference across the cell membrane in millivolts

established by diffusion potentials

Answer 21

resting membrane potential

Question 22

generation of resting membrane potential

Answer 22

selective membrane permeability

sodium potassium pump

concentration of the intracellular impermeable ions

Question 23

more K leak channels in the membrane

K channels are leakier compare to Na channels

concentration of K is greater inside than outside; movement is from inside to outside

Answer 23

high permeability to potassium

Question 24

electrogenic pump

generates and maintains the ionic concentration gradient

indirect contribution

Answer 24

sodium potassium pump

Question 25

state in which membrane is polarized at rest, negative inside and positive outside

Answer 25

polarization

Question 26

membrane potential becomes less negative than resting potential (close to zero)

Answer 26

depolarization

Question 27

membrane potential is more negative than the resting membrane

Answer 27

hyperpolarization

Question 28

restoration of normal polarization state of membrane

Answer 28

repolarization

Question 29

will reduce efflux of K+ leads to depolarizarition

Answer 29

hyperkalemia

Question 30

accelerate efflux of K+ leads to hyperpolarization

Answer 30

hypokalemia

Question 31

produced by weak stimulus

small deviation from the resting membrane potential of -70 mv

travels a short distance (local spread) from point of stimulus and eventually dies out (cannot propagate)

signals are graded

can undergo summation

can be depolarizing

Answer 31

local potential

Question 32

multiple stimulus fired simultaneously

Answer 32

spatial summation

Question 33

1 stimulus but fired fired repeatedly the response will also increase

Answer 33

temporal summation

Question 34

property of excitable cells

stereotypical in shape

propagating

all or none

non decremental

always excitatory

does not undergo summation

Answer 34

action potential