pumps and ion exchangers Flashcards
why are calcium levels low inside cells
because it is toxic if is too high and its need to be kept low so an increase can result in cell signalling
name all the types of calcium transporter
sodium potassium pumps sets up gradient allowing NCX to remove most of the calcium. Then PMCA removes the residue calcium. SERCA reabsorbs it into ER and hydrogen it pumped out at the same time. Mitochondria can also absorb ca2+ but this damages it and only happens in emergency
what happens to NCX when membrane potential swaps
The direction the ions are pumped in are also swapped. na+ is pumped out and ca2+ is pumped in. This is what causes the increase in calcium during a cardiac action potential. once membrane is repolaried it swaps back
what is ischaemia and what does it cause
lack of o2 and therefore low ATP. not enough ATP for sodium potassium pump and therefore sodium builds up in cell causing it to be depolarised. NCX therefore reverses and calcium is pumped in. This is toxic
transporters which control cell pH
sodium potassium pump sets up gradient. To decrease acidity NBE and NHE used. to increase alkali use cotratranport to get hco3- into cell with Na+. to decrease alkali use an AE. LOOK AT THIS SLIDE MORE TO SEE WHAT THEY DO
how is the set point of pH set
its controlled by the transporters. The part where they cross on the graph is the set point where the rate of each is the same. That is the set pH. as H+ increases more active in removing H+ and when pH high then more HCO3- pumped out
how is cell volume regulated
if cell is swollen pump ions out so water follwos and if its shunken pump ions in and water follows increasing cell volume
bicarbonate reabsorption by proximal tubule
HCO3- is reabsorbed by blood from kidney. draw the route can’t write it on here
renal control of Na+
used to treat hypertension. (high blood pressure). This means if you block exit of sodium then you block exit of water meaning blood pressure with be lowered
