Ion Exchangers Flashcards
What happens if intracellular calcium levels are high?
- If combined with phosphate tissues crystallise
- Toxic
Name 2 primary active transport mechanisms in intracellular calcium control
PMCA - expels Ca2+ out of the cell
SERCA - accumulates Ca2+ into the ER
Name 2 secondary active transport mechanisms in intracellular calcium control
NCX - Na+/Ca2+ exchange
Mitochondrial Ca2+ Uniports - buffer toxic Ca2+ levels
What happens when NCX polarises or depolarises a cell in terms of calcium and sodium concentration?
Polarised Cell - Increased Ca2+ and decreased Na+ in cell
Depolarised Cell - Decreased Ca2+ and increased Na+ in cell
How does NCX and Na+ pump play a role in ischaemia when ATP levels are low?
- Low ATP increase Na+ in cell as Na+ pump cannot work without ATP
- NCX process reverses caused intracellular Ca2+ to increase
Name 2 acid extruders and 1 base extruder used in control of cell pH
Acid Extruders - NHE, sodium bicarbonate co-transporter (NBC)
Base Extruders - Anion Exchanger (AE)
What is the intracellular pH set point defined by?
The combination of ion transporters
How is cell volume regulated?
Movement of osmotically active ions which move with water
What happens in terms of ion movement when a cell shrinks and when a cell swells?
Cell Swelling - ions move out of the cell
Cell Shrinking - ions move into the cell
Is cell volume regulation the same in all cells?
No, different cell types use particular combinations of transporters to achieve regulation
Why does the kidney reabsorb bicarbonate?
To retain the base for pH buffers
Which 2 ion transporter mechanisms are involved in bicarbonate reabsorption?
- Na+ pump
- NBC
What can be treated by altering kidney Na+ re-uptake?
Mild hypertension
Name 3 types of drugs or drugs used to treat hypertension by altering kidney Na+ re-uptake?
- Loop diuretics
- Thiazides
- Spironolactone
How does Spironolactone reduce blood pressure?
- Blocks ion Channels stimulated by Aldosterone
- Reduces Na+ in cell
- Increases water excretion
