Nerves 2 Flashcards
What does the Resting Membrane potential do?
like a battery being charged up and ready to go - keeps cell ready to respond
What is the Resting Membrane Potential?
about -70mV
What is meant by the equilibrium potential?
the membrane potential at which the electrical gradient is exactly equal and opposite to the concentration gradient
What is the resting membrane dependent on?
the permeability of the membrane to potassium
What happens to the heart if there is too much potassium in the body?
the heart does not have the same barrier mechanisms as the brain and so when there is a higher concentration of potassium, the concentration gradient is reduced and in turn the electrical gradient is reduced and so the RMP is reduced and the cell depolarises (gets more positive).
Hyperkalemia causes ventricular fibrillation
What causes the blood/brain barrier?
capillaries of the brane are especially ‘tight’ due to astrocytes and tight junctions between endothelial cells
this protects the brain from changes in plasma potassium
What is the resting membrane potential for started muscle?
-90mV
Why is the RMP close to potassium equilibrium?
at rest there are lots of potassium channels open
Why is the normal RMP closer to -70mV?
Due to other leaky channels such as Na+ and Cl-
Wjhat is the RMP dependent on?
the potassium concentration gradient set up by the sodium/potassium pump
