Nerve Physiology

Front 1

What does the Na+/K+ pump do?

Back 1

It sets up a concentration gradient ONLY. With more Na outside the cell and more K inside. As K moves down it's gradient (and + ions leave the cell), THAT generates the negative membrane potential.

Front 2

When is an ion in equilibrium in a cell?

Back 2

When the cell membrane potential (the electric force) = the ion equilibrium potential (the diffusion force) "the Nernst potential"

Front 3

Describe the time dependence of Na channel conformational changes

Back 3

Membrane depolarization makes Na channels open faster. However, after being open the channels inactivate and go through a period of nonconduction

K channels open slower

Front 4

Define the nerve action potential refractory periods

Back 4

Absolute-no Action potentials can occur here b/c most K are open and most Na are inactive


Relative-some ap's can occur. However they will be smaller b/c some Na are inactive and some k channels are open

Front 5

Define the patch clamp technique

Back 5

Inserting two electrodes to measure the voltage across a section of an axon

Front 6

Describe the general structure and properties of cell membranes

Back 6

Permeable to water & hydrocarbon-like molecules (uncharged molecules)

Nonpermeable to ions, proteins (charged molecules)

Front 7

List the type and concentration of some the key ions in cells and the extracellular fluid

Back 7

Outside Inside
Na+ 140mM 10mM
K+ 4mM 140mM
Ca2+ 2.4mM 50nM

Front 8

Define osmotic equilibrium

Back 8

A permeant solute is in osmotic equilibrium when there's = [] inside and outside the cell.

A cell is in osmotic equilibrium if the extracellular and intracellular []'s of ALL impermeant solutes are equal.

Front 9

Define the Nernst potential and compute is value

Back 9

Nernst Potential = the ion equillibrium potentil. the "force of diffusion".

= 61/(valence of ion) x log [external conc. /internal conc.]

Front 10

Steps in Nerve Physiology

Back 10

1) How Membrane Potentials are Generated
2) How voltage gates Na/K Channels work
3)

Front 11

Describe the general topology of v-gated K & Na channels

Back 11

They are proteins with a hole in it that will open if the plasma membrane is depolarized. There are 6 alpha helix membrane spanning parts. Every third aa is + (it's a voltage sensor).

Front 12

What is an action potential

Back 12

A temporary reversal of polarity in the membrane potential

Front 13

How does axon diameter affect AP conduction velocity?

Back 13

The larger the axon, the greater the velocity

Front 14

Define the basic properties of myelin

Back 14

It increases the action potential velocity as the action potentiol jumps from node to node. Very little conduction is lost to background channels.

Front 15

What are background channels?

Back 15

They are non-voltage gated ion channels that leak ions and therefore help set the resting membrabe potential. These channels cause the resting potential to be more positive than the Nernst potential.

Front 16

How does the action potential propogate?

Back 16

It's "boosted" by Na channels every so often so it doesn't die out via leakage via background channels.

Front 17

What causes the symptoms of multiple sclerosis?

What can make it worse?

Back 17

The Demylenation of axons results in:
slow conduction or worse, no conduction.

elevated temperature (such as fever) can exacerbate the symptoms.

It's likely an autoimmune disease of unknown etiology.

Always affects Causasions and women 2:1.

Front 18

Define Pharmacology

Back 18

The study of the interaction of chemicals wiht biological systems

Front 19

Define Pharmokinetics vs. Pharmodynamics

Back 19

Kinetics = What the body does to the drub (absorbtion, excretion, distribution)

Dynamics = What the drug does to the body (effects and mech of action)
The dynamics are more dynamic, in my opinion.

Front 20

What do most drugs interact with?

Back 20

A protein within the cell or on the surface of a cell

Front 21

Give some examples of common proteins that drugs affect

Back 21

Enzymes, transporters, ion channels, receptors. Two kinds of receptor effects: agonists turn on receptors, antagonists block receptors.

Front 22

Define pharmotherapeutics

Back 22

The use of drugs to prevent and treat disease

Front 23

Definie Toxicology

Back 23

Study of the adverse affects of chemicals or drugs

Front 24

Clinical pharmacology

Back 24

Study of drug effects on humans

Front 25

What are the different types of names for drugs?

Back 25

Chemical-acetylsalicyclic acid
Generic-Aspirin (decided by U.S. Committee)
Trade-Brand name

Front 26

What are the adverse effects of thalidomide

Back 26

It caused horrible malfornations in the children of preganant women who took the drug in the early 60's. It was an anti-depressant.

Front 27

Steps on modern drug development

Back 27

1) Drug Discovery (serendipidous, rational, screening of animals)
2) Preclinical drug eval (animal testing, LD 50 determined (lethal dose for 50% of individuals), toxicity)
3) Clinical drug eval- Investigatinal New Drug app to the FDA and Clinical Trial

Front 28

Phases of Clinical Trials

Back 28

1- Dose response, toxicity on healthy humans
2- efficacy in sick patients
3- randomized, controlled trial
4-avail to prescribers