Membrane transport
MEMBRANE TRANSPORT · IMAT Doutor1 / 1
Ouabain blocks the sodium–potassium pump, causing sodium to accumulate inside a cardiac cell. What happens to the intracellular calcium concentration?
A
It rises, because the pump normally brings calcium into the cell together with potassium
B
It rises, because the sodium-calcium exchanger depends on the sodium gradient to expel calcium
C
It falls, because less sodium enters and the calcium channels depend on sodium entry to open
D
It does not change, since calcium transport in the cardiac cell is independent of sodium
E
It falls, because the pump also transports calcium into the sarcoplasmic reticulum
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