Question

Case: Henry has climbed to the top of Mt. Apo. This is one of his bucket lists. Hence, to celebrate, he drinks 2 glasses of whiskey.

A. At higher altitude oxygen gas decreases. What do you expect to happen to Henry's respiratory rate? Will this result to respiratory alkalosis or acidosis? Explain.

B. How will Henry's body regulate this acid-base imbalance?

C. Alcohol stimulates hydrochloric acid secretion in the stomach. Explain how stomach secretions are regulated during Henry's intake of alcohol.

Answer 1

1. As Henry is at high altitudes, the partial pressure of oxygen in the environment decreases. Therefore to combat this, the body does two thing's:-

• Increase the RBCs number by stimulation of erythropoietin
• Hyperventilate to remove excess of carbon dioxide.

As the body does hyperventilation, the respiratory rate INCREASES. Hyperventilation removes the carbon dioxide in excessive amounts which lead to decrease in pCO2. As carbon dioxide is acid, the concentration of acid decrease and RESPIRATORY ALKALOSIS happens.

Respiratory alkalosis is compensated by Renal mechanism which will try to reabsorb H ions and excrete excess of HCO3.

• Hydrogen ion secretion by the tubular cells is reduced. Hence the amount of hydrogen ions is inadequate to reabsorb all the filtered Bicarbonate, so substantial quantities of bicarbonate are excreted in the urine.
• There will be little or no excretion of hydrogen ions bound to non bicarbonate urinary buffers.
• Tubular glutamine metabolism and ammonium excretion are decreased. This lowers the excretion of hydrogen ions and new bicarbonate is added to the plasma from this source.
• With the reduced reabsorption and no addition of a new Bicarbonate, plasma bicarbonate concentration is decreased thereby compensating for the alkalosis

Alcohol affects the Gastrin Hormone secreted by the G cells in antrum of stomach. Gastrin stimulates the parietal cells to produce acid. Alcohol in low content as in beer, etc stimulates the G cells to produce gastrin. On the other hand, beverages like whiskey which contains more amount of alcohol inhibits the G cells. Therefore, lesser G stimulation, lesser gastrin and lesser acid secretion.