13. Buffers of physiological importance Flashcards
What is the pH of blood plasma
7.4
3 buffer system that can be used to regulate blood pH
- Bicarbonate/ carbonic acid (extracellular)
- Phosphate buffer (intracellular)
- The Histidine side chain of proteins
Describe The phosphate buffer system
The most important intracellular buffer system.
Phosphoric acid is a triprotic acid and this buffer is working within the second buffering range pka=7.2
The phosphate buffer consists of phosphoric acid (H3PO4) in equilibrium with dihydrogen phosphate ion (H2PO4-) and H+.
Describe bicarbonate/carbonic acid buffer system
- The most important buffer for maintaining a steady pH in the body.
Why is the bicarbonate buffer a super buffer for the blood?
Because of 3 things ventilation, the kidney and specific proteins.
How can the bicarbonate buffer involve in ventilation?
CO2 concentration is regulated by ventilation.
- amount of CO2 gets out of the system and this changes the pH dramatically.
- Too much acid in your blood → hyperventilate
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What is acidosis?
a condition in which there is too much acid in the body fluids
→ results from poor lung function or depressed breathing (respiratory acidosis)
→ HYPERVENTILATION
What is Alkalosis?
It occurs when your blood and body fluids contain an excess of bases or alkali
→ results from rapid or deep breathing
→ HYPOVENTILATION
How can the bicarbonate buffer involve in kidney function?
The kidneys help maintain the acid–base balance by excreting hydrogen ions into the urine and reabsorbing bicarbonate from the urine (removal of acids from the body).
How can the bicarbonate buffer work with RBC?
Rbc’s contribute to the stabilization of the pH by H+removal/regulation via the protein hemoglobin.
Describe reaction Between 𝐶𝑂2 and Water
The reaction can be catalysed by the enzyme carbonic anhydrase.
