Blood pH is normally regulated by the respiratory system to control the level of
ID: 226953 • Letter: B
Question
Blood pH is normally regulated by the respiratory system to control the level of CO. (g) and by the urinary system to control the levels of HCO_3^- and non-volatile adds in the blood. Given the overall reaction. CO_2 (g) + H_2O (l) H_2CO_3 (aq) HCO_3^- (aQ) + H^+ (aq), what effect would each of the following have on blood pH? Explain. a. Hyperventilating b. Holding your breath for an extended period of time c. Chronic diarrhea d. Excessive ingestion of baking soda One of the effects of Topamax is to inhibit carbonic anhydrase. Predict the effect of Topamax on the function of each of the following cells: a. Osteoclasts (bone) b. Parietal cells (stomach) c. Red blood cells (blood) d. Epithelial cells of the proximal tubules (kidney) The carbonic anhydrase in proximal tubule epithelial cells are particularly sensitive to inhibition by Topamax. Use the diagram of transport in the epithelial cells of the proximal tubule provided on next page" and your understanding of the function of the kidney to provide a step-by-step explanation of how the inhibitory action of Topamax caused the disturbances in Mary's blood chemistry.Explanation / Answer
3.a) During hyperventilation CO2 leaves the plasma rapidly and H+ combines with bicarbonate to make more carbon di oxide and the reaction proceeds to the left . As H+ is used up, plasma becomes more basic and blood pH increases.
b) If one holds his breadth for an extended period of time,then CO2 will be produced in the tissues but because of lack of gaseous exchange in the lungs, CO2 will be accumulated in the plasma and the equilibrium will shift to the right which will lead to an increase of H+ ion and decrease in blood pH.
c) During chronic diarrhoea,intestinal bicarbonate ions are lost from the body. The fluid left in the body have lower base content than normal. This results in decrease in pH of the plasma and acidosis.
d) Baking soda contain bicarbonate ion. As concentration of HCO3- increases in the body, it will react with H+ and produce carbon di oxideThis results in decrease of H+ ion and increase in the pH of the blood.
4.a) Bicarbonate helps in maintaining calcium in the bone,decrease its excretion. In presence of topamax, the carbonic acid inhibitor, bicarbonate will not be produced and it will lead to loss of calcium from bones making them weak and brittle.
b) The parietal cells in the stomach secrete hydrochloric acid. The H+ are generated from dissociation of water. The OH- ions generated react with carbon di oxide to form bicarbonate ion catalysed by carbonic anhydrase. Use of topamax inhibits carbonic anhydrase. So as a feedback mechanism H+ generation will fall leading to decreased acid secretion.
c) Topamax as carbonic anhydrase inhibitor increases the amount of CO2 in the blood and an increase in pH.
d) Carbonic anhydrase catalyses the breakdown of HCO3-- in the epithelial cells of the proximal tubules of the kidney. When it is inhibited by Topamax, bicarbonate concentration will increase with an increase in pH.