Pump And Ion Exchangers Flashcards
What is the function of the Na-K ATPase (Na pump)
2
- To form Na and K gradients
- drive secondary active transport
How many MTV does the Na-K ATPase pump contribute to the resting membrane potential?
5mV
What is the role of PMCA? (Plasma membrane calcium ATPase)
Expels residual calcium out of the cell
What is the affinity of PMCA like?
Low
What is the capacity of PMCA like?
High
What is the function of SERCA?
Removal of residual calcium into the SR
What is the affinity of SECRA like?
Low
What is the capacity of SERCA like?
High
What is the function of mitochondrial Ca uniports?
Operate at high calcium concentrations to buffer potentially damaging calcium
What is the function of NCX?
Expels intracellular calcium during cell recovery
Name the two channels involved in active transport.
PMCA
SERCA
Name a channel which uses secondary transport to function
NCX
Name a channel which uses facilitated transport to move ions.
Motchindrial ca uniports
What does the NCX exchange?
3 Na in for 1 ca out
What happens to the NCX during ischemia?
- ATP depleted therefore the Na pump is depleted
- Na accumulates depolarising cell
- NCX reverses
- Toxic calcium pumped into cell
