Question

Which of the following statements about blood acid/base balance is true?

Select one:

a. Carbonic anhydrase is a membrane protein that transports bicarbonate ion from the filtrate into the tubular epithelium

b. The phosphate buffer system is the primary extracellular buffer

c. Urinary excretion of hydrogen ion bound to phosphate buffers will increase plasma bicarbonate concentration

d. Hydrogen ion binds to filtered bicarbonate in the tubular fluid, then both are excreted in the urine.

Answer 1

Answer :A.Carbonic anhydrase is a membrane protein that transports bicarbonate ion from the filtrate into the tubular epithelium.

Explanation : Carbonic anhydrase is an enzyme that transport bicarbonate and Hydrogen into Carbondioxide and water and due to this reabsorption of bicarbonate take place because The kidneys normally reabsorb all bicarbonate ions that are filtered at the glomerulus.

Note : carbonic anhydrase inhibitors drugs like Acetazolamine will inhibit all the above process and inhibit reabsorption .

The kidneys can filter and secrete H+ into the tubular filtrate and Filtered bicarbonate present in the filtrate is reabsorbed into the blood indirectly as CO2 gas....Thanks