Lecture 7: Resting Membrane Potential Flashcards
When measuring membrane potential the convention is
inside with respect to outside
Cells maintain gradients of ions by means of
primary active transport
It requires what to separate charges?
Energy
Charges move through ______ and are separated by _____
Conductors and insulators
Define electrochemical gradient
A Combination of an Electrical gradient and a chemical gradient
Ions subjected to an electrochemical gradient will
move
The Membrane potential of a cell is due to what
the electrical gradient across a cell membrane due to the unequal distribution of charges (ions)
Membrane is measured in what unnits
Millivolts or mV
True or False; Membrane potential is static
false; not constant
The resting membrane potential (RMP) is a
special case of steady-state balance between active transport and leakage of ions
True or false; A steady state is not an equilibrium
true
For most cells the RMP is typically between what
-20 mV and -90mV
Define Depolarizing, repolarizing, hyperpolarization
Depolarizing = membrane potential moving towards 0 Repolarization = membrane potential becoming more negative to initial stage Hyperpolarization = making a membrane potential more negative past initial stage
The amount of voltage necessary to keep the molecule inside the cell is called the
equilibrium potential
Define equilibrium potential
The membrane potential that exactly opposes the steady state electrochemical gradient for an ion
When calculating the equilibrium potential we calculate it at what temperature
37 degrees Celsius
We use the what equation to calculate equilibrium potential and what is it
Nernst Equation
Eion = 61/z X log (ION out/ ION in)
Is the equilibrium potentials positive or negative for the following ions K+ Na+ Ca2+ Cl-
K+ = negative Na+ = positive Ca2+ = positive Cl- = negative
The equilibrium potential for each ion is ______________ of the concentration of the other ions
independent
What is the relative number of leakage channels (Relative permeability) of; K+ Na+ Ca2+ Cl-
K+ = 50 Na+ = 1 Ca2+ = 0 Cl- = 10
When predicting the RMP we use what equation
Goldman
The Goldman equation is basically what
3 nrest equations put together
Write the Goldman Equation for Na+, K+ and Cl-
RMP = 61 log ((((P of k (K+ out) + P of Na (Na+) out + P of Cl (Cl-) IN ///////// P of K (K+) in + P of Na (NA+) in + P of Cl (Cl-) OUT )))
What is the RMP for a normal healthy person
-78
What is the RMP for a person with kidney failure caused by what
-67
caused by elevated K+ out
What is the RMP for sever diarrhea and what caused it
-89
Decreased K+ out
K+ typically moves ____ of the cell when it opens, where the other salts typically more ____
out; in
To understand why ions move the way they do we need to consider both ______ and ______
Equilibrium potential
Membrane potential of the cell
When ion channels open the ion always moves to make what = what
membrane potential = equilibrium potential
