L02: Membrane Physiology Flashcards
What is the role of ion pumps
Maintain concentration gradients
What does ion pumps not do
Create membrane potential
What is the membrane potential
Potential of a cell during rest
What is the average value for membrane potential
-65mv
What are the 3 types of ion channels found on cell membranes
Non-gated ion channels
Voltage gated ion channels
Ligand gated ion channels
Which major channel is involved in generating the membrane potential
Non gated ion channels
What are the specific non-gated ion channels that set up the membrane potential
Sodium non gated ion channel
Potassium non gated ion channel
What are the factors that influence membrane potential
Chemical gradient
Electrical force
What is a chemical gradient
The concentration gradient of a specific source e.g ion
What is an electrical force
Ions that are attracted to potentials
What happens to sodium and potassium ions at a negative membrane potential
Attracted inside the cell because they are positive ions
What happens to sodium due to its chemical gradient
Moves into the cell because it is high outside
What happens to potassium due to chemical gradient
Moves outside the cell because it it high in concentration inside the cell
Why does the chemical gradient not change a lot
Because the movement of ions is small
What is an equilibrium potential
No net movement of ions
What is the equilibrium potential of potassium
-80mv
What is the equilibrium potential of sodium
+62mv
What does the equilibrium potentials indicate for sodium and potassium
At those values there are no net movements of sodium or potassium
What is the membrane potential of cells
-65mv
Describe the movement of sodium and potassium in generating a membrane potential of -65mv
Potassium efflux : chemical gradient is greater than electrical force
Sodium influx: chemical gradient and electrical force cause it
At rest which ion has a greater permeability
Potassium has 40x greater permeability than sodium
What is the name of the ion pumps that Maine’s the chemical gradient
Sodium-potassium pump
How does a sodium-potassium pump work
3 sodium out
2 potassium in
ATP is used
