Hsf: Bioelectric Phenomena

Front 1

Examples of Medical Diagnostic Tools: Electrical Activity in Organs

Back 1

-Electrocardiogram (ECG or EKG)
-Electromyogram (EMG)
-Electroretinogram (ERG)
-Electroencephalogram (EEG)

Front 2

What do the medical diagnostic tools for electrical activity take measurements of?

Back 2

-Voltage induced b/w a pair of electrodes by currents flowing through cells in the heart, skeletal muscle, the retina, and the brain

Front 3

Cells are able to generate electrical signals b/c of specialized ___________ _______ ________ ________.

Back 3

-Membrane protein ion channels

Front 4

The _____ ______ nature of the hydrocarbon chains of the phospholipids makes the bilayer a formidable barrier to ion movements.

Back 4

-Non-polar

Front 5

The lipid bilayer restricts the movement of the _____ _____ molecule.

Back 5

-Polar water

Front 6

What substances can easily cross lipid bilayer?

Back 6

-Water (due to fluidity of membrane)
-Gases
-Small, nonpolar substances
-Small, hydrophobic drug molecules

Front 7

Types of substances that cannot pass through lipid bilayer

Back 7

-Large polar or charged molecules
~Sugar and Amino Acids

Front 8

Are ions hydrated?

Back 8

Yes

Front 9

Why are ions hydrated?

Back 9

-the charges on the ions attract the dipolar water molecules

Front 10

What type of backbone do proteins in cell membrane favorable to ions have?

Back 10

-lipophilic backbone

Front 11

Types of substances that cannot pass through lipid bilayer

Back 11

-Large polar or charged molecules
~Sugar and Amino Acids

Front 12

Are ions hydrated?

Back 12

Yes

Front 13

Why are ions hydrated?

Back 13

-the charges on the ions attract the dipolar water molecules

Front 14

What type of backbone do proteins in cell membrane favorable to ions have?

Back 14

-lipophilic backbone

Front 15

Roles of Ion Channel for Body Systems

Back 15

-Cellular Electrical Activity is generated
-Nerve Excitability
-Proper Execution of physiological roles

Front 16

An increasingly large list of _____ _______ are based on defects in ion channel proteins and ion channels are the targets of many ______ _______ diseases.

Back 16

-Genetic Diseases
-Environmentally-Caused Diseases

Front 17

What is a resistor and what units is it measured in?

Back 17

-The device that lets current flow through it.
-Ohms

Front 18

Ohm's Law Equation

Back 18

V=IR

-I=current in amps
-R=Resistance
-V=Voltage

Front 19

The smaller the resistance, the ______ the current.

Back 19

Larger

Front 20

Conductance Equation

Back 20

G=1/R

G--> measured in mho or Siemans

I=GV--> the larger the conductance (more conducting) the more current flow.

Front 21

Are ion channels biological conductors?

Back 21

Yes

Front 22

Equation for 2 pores (Resistor and Conductance)

Back 22

Resistor:
1/Rtotal=(1/R1)+(1/R2)

Conductance:
Gtotal=G1 +G2

Front 23

Conductance of a typical protein pore

Back 23

10X10^-12mho or 10^11 ohms

Front 24

Size of typical mammalian neuronal cell body

Back 24

10um in diameter

Front 25

Is the lipid bilayer a resistor?

Back 25

No, its a capacitor

Front 26

What is a capacitor?

Back 26

-Usually a structure consisting of two conductors separated by an insulator
-Function: stores electric charge

Front 27

Equation for Capacitor

Back 27

C=Q/V

C-Capacitance (measured in Farads)
Q-Amt of Charge (measured in coulombs)
V-Voltage

Front 28

The _____ part of the cell membrane is a fine insulator and the _______ _____ inside and outside the cell are good conductors.

Back 28

-lipid part
-salt solutions

Front 29

Typical Capacitance of a cell membrane

Back 29

1uF per cm^2 of cell membrane area

Front 30

Which mentioned ions use carriers and pumps?

Back 30

-Na+
-K+
-Ca2+

Front 31

Example of ATP powered transport system

Back 31

Na-K ATPase "pump"

Front 32

Na-K ATPase Pump

Back 32

-Pumps Na+ ions out of the cell and K+ ions into the cell
-Controls the intracellular concentrations of these ions but at the expense of energy consumption

Front 33

Forces acting on substances that are being pumped in and out

Back 33

-Diffusion force
-Electrical force

Front 34

Nernst Potential Equation for K+ ions

Back 34

Vk= (RT)/F * ln[K0/Ki]
or
Vk= 61* log[K0/Ki] in MV at 37 degrees C

R-Universal Gas constant
T-absolute temperature in Kelvin
F-thermodynamic constant (Faraday)

Front 35

Farady

Back 35

-the amount of charge per mole of a substance

Front 36

Nernst Equation for ion X

Back 36

Vx= (RT/zF) * ln[Xo/Xi}

where z is the valence of ion x

Front 37

Goldman, Hodgkin, Katz Equation

Back 37

V(o)= (RT/F) ln ((P(Na)*[Na(out)] + P(K)[K(out)])/(P(Na)*[Na(in)] + P(K)[K(in)])

Front 38

Approximate Size of Cell and Plasma Membrane

Back 38

-Cell=~10um
-Plasma Membrane=~35A

Front 39

If both Na+ and KI channels are open, the membrane voltage will approach....

Back 39

-A value between E(Na) and E(K)

Front 40

Extracellular and Intracellular Fluid Concentrations: Na+

Back 40

-Outside: 140 mM
-Inside: 10 mM

Front 41

Extracellular and Intracellular Fluid Concentrations:K+

Back 41

-Outside: 4 mM
-Inside: 140 mM

Front 42

Extracellular and Intracellular Fluid Concentrations: Ca 2+

Back 42

-Outside: 2.4 mM
-Inside: ~50nM

Front 43

Extracellular and Intracellular Fluid Concentrations: Mg2+

Back 43

-Outside: 1.2 mM
-Inside: 4mM

Front 44

Extracellular and Intracellular Fluid Concentrations: Mg2+

Back 44

-Outside: 1.2 mM
-Inside: 4mM

Front 45

Extracellular and Intracellular Fluid Concentrations: Mg2+

Back 45

-Outside: 1.2 mM
-Inside: 4mM

Front 46

Extracellular and Intracellular Fluid Concentrations: Mg2+

Back 46

-Outside: 1.2 mM
-Inside: 4mM

Front 47

Extracellular and Intracellular Fluid Concentrations: Cl-

Back 47

-Outside:103mM
-Inside: 58 mM

Front 48

Extracellular and Intracellular Fluid Concentrations: Cl-

Back 48

-Outside:103mM
-Inside: 58 mM

Front 49

Extracellular and Intracellular Fluid Concentrations: HCO3

Back 49

-Outside: 28mM
-Inside:10 mM

Front 50

Extracellular and Intracellular Fluid Concentrations: Cl-

Back 50

-Outside:103mM
-Inside: 58 mM

Front 51

Extracellular and Intracellular Fluid Concentrations: Cl-

Back 51

-Outside:103mM
-Inside: 58 mM

Front 52

Extracellular and Intracellular Fluid Concentrations: SO4 (-2)

Back 52

-Outside: 1mM
-Inside: 2mM

Front 53

Extracellular and Intracellular Fluid Concentrations: HCO3

Back 53

-Outside: 28mM
-Inside:10 mM

Front 54

Extracellular and Intracellular Fluid Concentrations: HCO3

Back 54

-Outside: 28mM
-Inside:10 mM

Front 55

Extracellular and Intracellular Fluid Concentrations: HCO3

Back 55

-Outside: 28mM
-Inside:10 mM

Front 56

Extracellular and Intracellular Fluid Concentrations:Phosphates

Back 56

-Outside: 4mM
-Inside: 75mM

Front 57

Extracellular and Intracellular Fluid Concentrations: SO4 (-2)

Back 57

-Outside: 1mM
-Inside: 2mM

Front 58

Extracellular and Intracellular Fluid Concentrations: SO4 (-2)

Back 58

-Outside: 1mM
-Inside: 2mM

Front 59

Extracellular and Intracellular Fluid Concentrations: SO4 (-2)

Back 59

-Outside: 1mM
-Inside: 2mM

Front 60

Extracellular and Intracellular Fluid Concentrations:Phosphates

Back 60

-Outside: 4mM
-Inside: 75mM

Front 61

Extracellular and Intracellular Fluid Concentrations:Phosphates

Back 61

-Outside: 4mM
-Inside: 75mM

Front 62

Extracellular and Intracellular Fluid Concentrations:pH

Back 62

-Outside; 7.4
-Inside: 7.0

Front 63

Extracellular and Intracellular Fluid Concentrations:pH

Back 63

-Outside; 7.4
-Inside: 7.0

Front 64

Extracellular and Intracellular Fluid Concentrations:Phosphates

Back 64

-Outside: 4mM
-Inside: 75mM

Front 65

Extracellular and Intracellular Fluid Concentrations:pH

Back 65

-Outside; 7.4
-Inside: 7.0

Front 66

Extracellular and Intracellular Fluid Concentrations:pH

Back 66

-Outside; 7.4
-Inside: 7.0