Chapter 5- Membrane and Action Potentials Flashcards
what do all cells have …
a plasma membrane
what is in the plasma membrane
-lipid bilayer
how do fat soluble molecule pass through the plasma membrane
diffusion
how do water soluble molecule pass through the plasma membrane
require a protein channel inserted in the membrane to pass
what do all cells have a difference in
electrical potential between the ICF and the ECF
what can change these electrical potentials
- nerve and muscles can change potential rapidly
- profound change in potential
- excitable cells
- able to produce an action potential
what do non excitable cells use
changes in membrane voltage for signaling, but not via an action
what is voltage
this is a relative phenomenon
how do you measure voltage
with 2 electrode for recording
how is RMP established
the balance of electrical and chemical properties of the cell
what laws do ions follow
the the law of diffusion down a concentration gradient and they are also subject to electrical forces such as charges, repel, opposites attract
what is the only way you can measure voltages
charges must be going through a resister
what happens when a positive charge leaves the cells
the inside becomes more relatively negative which creates a more negative electrical potential inside
where is voltage generated in a cell
across the membrane
when will positive charges stop leaving the cell
when the diffusion gradient equals the electrical gradient
when is there no net movement of an ion
when the electrical and diffusion forces are equal and opposite
what is the equilibrium
this is when an ion stops its movement
what is the nernst potential
the potential across a membrane that exactly opposes the net diffusion of a particular ion through the membrane
NEED TO KNOW the equations
what is the magnitude of the nernst potential determined
by the ratio of the concentrations of the specific ion on the both sides of the membrane
what happen when the nernst potential has a greater ratio
the greater the ratio the greater the tendency for the ions to diffuse in one direction and is required to prevent additional net diffusion
what is the potential in extracellular fluid
this is outside the membrane an its has a zero potential
what is the potential for the nernst
this potential is on the inside of the membrane
when is the sign of the nernst potential is positive (+)
if the ion diffusion form inside of outside is a negative ion
when is the sing of the nernst potential is negative (-)
if the ion diffusion from inside to outside is positive
