Maintenance of pH Flashcards
At what pH do most physiological processes occur at within cells?
pH 5-7.6
What is the normal plasma pH?
7.4
What is the normal pH of the pancreatic juice?
8.8
What is the normal pH of the stomach?
pH 2 (1-3)
What strategies are used to regulate pH within the body?
Partitioning
Buffering
What is partitioning?
Transferring H+ ions from areas of higher/lower concentrations using proton pumps
What is the main buffering system in the body?
Carbonic anhydrase working in circulation and tissues
How does the carbonic anhydrase buffer system work?
C.A is an enzyme
CO2 + H2O <=> H2CO3 <=> HCO3- + H+
Give an example of a cell where the carbonic anhydrase buffer system is used?
In parietal cells in the gastric glands of the stomach.
What form of amino acid is pH dependent?
Ionic forms of amino acids
What is the biomedical significance of pH?
We can use H+ ions as a biomarker
pH changes can be exploited by toxins and viruses
pH must be controlled to maintain proper protein conformations
What happens to proteins if the pH is not regulated?
Fluctuations in pH may mena that the amino acids do not ionise properly leading to incorrect protein conformations and thus non functional proteins.
What issues arise when pH strays too far from normal?
Can lead to metabolic acidosis or metabolic alkalosis
What is the response to acid-base imbalances in the body?
- Buffering and H+ partitioning
- Alteration in arterial pCO2
- Alteration in HCO3- excretion.
How does pH affect drug uptake?
weak acid/base drugs will in water dissociate to some extents but this is regulated by the pH.
Drugs can only cross membranes in their uncharged forms.
