Membrane Potential II Flashcards
How can the Na+ pump be blocked?
by interfering with ATP production (e.g., low temperature, cyanide, hypoxia) or by specific drugs
The Principle of Electrical Neutrality
bulk solutions have to be electrically neutral
The sodium/potassium pump is electrogenic, meaning that _____.
the Vm gets a little more negative than it otherwise would be
What opens the inner gate on the sodium/potassium pump?
ATP binding
the Donnan Rule equation
[K+]o x [Cl-]o = [K+] i x [Cl-]i
Ohm’s Law equation
I = (driving force) x G
If the Na+ pump is blocked, _____.
Na+ enters the cell, water follows, and the cell swells
The diagnosis of _____ usually is via an electrocardiogram (EKG) to detect cardiac arrhythmias, followed by measuring plasma potassium ion concentration.
hyperkalemia
The sodium pump is really an _____ pump.
obligatorily coupled sodium-potassium exchange
[K+]o x [Cl-]o = [K+] i x [Cl-]i
the Donnan Rule
What drugs block the Na+ pump?
cardiac glycosides, which includes digitalis, ouabain, strophanthidin, and others
What happens when the outer gate opens on the sodium/potassium pump?
the affinity changes from Na+ to K+
What is a drastic way to cleanse potassium from the blood?
dialysis
What is the typical cell membrane resting potential?
-80 mV
What is G in Ohm’s Equation?
1/R
What is the sodium/potassium pump ratio?
3 Na+ for 2 K+
The Na/K pump is “_____”, that is, it has an easily demonstrable maximum rate of activity of only about 100 cycles per second.
saturable
In acute hyperkalemia, the main danger concerns the reliable conduction of electrical signals (action potentials) in ___.
the heart
Both ____ and ___ ions must be present simultaneously or the pump won’t work.
Na+; K+
What closes the outer gate on the sodium/potassium pump?
phosphate dissociates
What does R stand for in Ohm’s Equation?
membrane resistance to the ion
The higher the permeability, the _____ the conductance..
higher
Membrane potential is determined by relative ______.
conductance
What does V stand for in Ohm’s Equation?
the driving force of the ion
What closes the inner gate on the sodium/potassium pump?
ATP splitting, leaving the phosphorylation
Hyperkalemia is caused from _____.
loss of potassium from cells
In real cells, the big ions (mostly proteins, SO4, and HPO4) carry a net ____ charge.
negative
The diagnosis of hyperkalemia usually is via an ___ to detect cardiac arrhythmias, followed by measuring ____.
electrocardiogram (EKG); plasma potassium ion concentration
What does I stand for in Ohm’s Equation?
the current
Why does K+ leave the inside of the sodium/potassium pump?
the gate opened and the affinity shifted to Na+
What does a steady state mean?
ion concentrations aren’t changing over time, but a constant input of energy is needed to drive pumps to keep it this way
The sodium/potassium pump is comprised of a large ____ subunit and a smaller ____ subunit.
alpha; beta
______ is determined by relative conductance.
Membrane potential
In ____, the main danger concerns the reliable conduction of electrical signals (action potentials) in the heart.
acute hyperkalemia
What provides the energy for the sodium/potassium pump?
ATP
Why do different cells in the body have different resting membrane potentials?
differences in relative permeability
The Na/K pump is “saturable”, that is, it has an easily demonstrable _____ of only about 100 cycles per second.
maximum rate of activity
When you CBIGK in a patient, what should you give, in order?
Calcium, Bicarb, Insulin + Glucose, Kayexalate
