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Resting Membrane
Phsyiology Week 5
Question | Answer |
---|---|
What is the importance of resting membrane potential? | It maintains a ready state for the cell to fire. W/o this potential, the functions of various organs would be impaired. |
What is resting membrane potential? | The difference in the amount of electrical charge inside and outside the cell. |
What is the most concentrated cation in extracellular fluid? | Sodium |
What ions are resting membranes most permeable to? | Potassium |
What is the resting membrane potential? on exam | -70 |
What are the three mechanisms responsible for maintain resting membrane potential? | sodium potassium pump, Passive diffusion of sodium-potassium Entrapment of proteins |
Two factors that influence a cell's membrane potential | The concentration gradients of different ions across the membrane and the permeability of the membrane to those ions |
What happens to the resting membrane potential of a cell if the extracellular K+ concentration increases? | It becomes more positive. |
What happens to the membrane potential of a cell that suddenly becomes more permeable to Na+? | If na+ goes inside cell, -ve ion moves out therefore it becomes more positive. |
Depolirization | becomes more positive from resting state (entry of Na+, Ca+) |
Repolarization | more negative (Na+ leaves) |
Hyperpolirization | Becomes more negative from resting state (entry of Cl-) |
What happens to membrane potential if intracellular K+ increase? | Decrease in membrane potential |
What causes changes in membrane potential & creates electrical signals? | The movement of one of four ions: Na+, Ca2+, CL- & K+ |
What is the resting membrane potential difference? | The electrical gradient b/w the extracellular fluid & the intracellular fluid |
Electrical Gradient | Although the body is electrically neutral, diffusion & active transport of ions across the cell membrane create an electrical gradient with the inside of cells -ve relative to the extracellular fluid |
What is the movement of an ion across the cell membrane influenced by? | The electrochemical gradient for that ion. |
Equilibrium Potential | The membrane potential that exactly opposes the concentration gradient of an ion is known as the equilibrium potential. The equilibrium potential for any ion can be calculated using the Nerst equation |
Charges of outside + inside cell | Outside cell: always positive Inside cell: always negative |