Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
28 Cards in this Set
- Front
- Back
|
What is the charge inside and outside of a cell?
|
inside = negative
outside = positive |
|
|
What increases a membranes potential?
|
increasing the magnitude of separated charge
|
|
|
what contributes to the majority of negative charge on the inside of a cell?
|
negatively charged Proteins
|
|
|
which is more permiable to the membrane, Na+ or K+?
|
K+
|
|
|
what maintains the high concentration of K+ on the inside of the cell?
|
the Na+/K+ pump
|
|
|
what are the general characteristics of ion channels?
|
water filled, transmembrane proteins
gated selective some are background channels some can enter an inactive state |
|
|
what is the Equilibrium potential?
|
when the magnitude of the electrical potential is equal to and opposite the chemical gradient
|
|
|
which is more powerful, the electrical force or the chemical gradient?
|
the voltage potential from a small distribution of ions is massive compared to the chemical gradient
|
|
|
what is the Nernst equation?
|
E ion = (60/z) log( [ion]out / [ion]in )
|
|
|
What do the E and the z in the Nernst equation stand for?
|
E = equilibrium potential
z= ion charge |
|
|
What are the typical values for the equilibrium potentials of K+, Na+, Cl-, Ca 2+ ?
|
K+ = -90
Na+ = +65 Cl- = -90 Ca 2+ = +120 |
|
|
What is the typical resting membrane potential for a cell in homeostasis?
|
-70mV
|
|
|
What is Ohms law used for?
|
calculating the membrane potential
|
|
|
what is Ohms Law?
|
Em= (gkEk + gNaENa + gClECl + gCaEca)/ (gK + gNa + gCl + gCa)
g = conductance |
|
|
What is the resting membrane potential almost entirely determined by?
|
K+ and Na+ concentrations
|
|
|
How is membrane permeability (g) changed?
|
By opening or closing ion channels
or by creating or endocytosing new/exsisting ion channels |
|
|
How does our body adapt to acute hypertension?
|
By increasing the number of and opening of Cl- ion channels. this leads to enhanced smooth muscle contraction
|
|
|
Why would opening K+ channels create a more negative Emem?
|
Because the K+ would move along its chemical gradient, but AGAINST its electromagnetic gradient. this would lead to a more negative intracellular condition, thus hyperpolarizing the cell.
|
|
|
Why would opening Na+ channels lead to a more positive Emem?
|
because the Na+ would move along both its electrical and chemical gradient into the cell. this would reduce the charge within the cell.
|
|
|
what do the words hyperkalemic and hypokalemic mean?
|
they refer to the K+ concentration gradient
|
|
|
why does hypokalemia lead to decreased muscle contractions?
|
it leads to hyperpolarization of the membrane. if the membrane is hyperpolarized, its harder to reach threshold for the action potential
|
|
|
What do the words hypo/hypernatremia refer to?
|
the Na+ electrical gradient
|
|
|
What makes the largest contribution to membrane potential?
|
facilitated Na+ and K+ ion channels, also known as background channels.
|
|
|
what drives the function of background channels?
|
Active transporters like the Na+/K+ transporter
|
|
|
Describe the effect on Emem for each of the following.
Increased ECF K+ conc. Decreased ECF K+ conc. |
Increase= depolarize
Decrease= hyperpolarize |
|
|
Describe the effect on Emem for each of the following.
Increased ECF Na+ conc. Decreased ECF Na+ conc. |
Increase= depolarize
Decrease= hyperpolarize |
|
|
Describe the effect on Emem for each of the following.
Increased ICF K+ conc. Decreased ICF K+ conc. |
Increase= hyperpolarize
Decrease= depolarize |
|
|
Describe the effect on Emem for each of the following.
Increased ICF Na+ conc. Decreased ICF Na+ conc. |
Increase= hyperpolarize
Decrease= depolarize |
