A middle-aged college professor from Boston is in the Swiss Alps studying astron

Question

A middle-aged college professor from Boston is in the Swiss Alps studying astronomy. He arrived two days ago and plans to stay the entire year. However, he notices that he is short of breath when he walks up steps and that he tires easily with any physical activity. His symptoms gradually disappear: after two months, he feels fine. Upon returning to the United States, he has a complete physical exam and is told that his erythrocyte count is higher than normal. (a) Attempt to explain this finding. (b) Will his RBC count remain at this higher-than-normal level? Why or why not?

Explanation / Answer

a) At higher altitude the air is less dense, thus making it difficult for the body to get the appropriate amount of oxygen. This results into 'hypoxia'. The most common symptom of hypoxia being shortness of breath on doing physical activity (which was observed in case of the Professor belonging to Boston who went to the Swiss Alps). But, on living for longer duration, the body tends to acclimatize. During the acclimatization, the number of RBCs as well as blood capillaries increase and also the lung capacity increases. All these changes enhance the better uptake and transportation of oxygen in the body at higher altitudes. So, the higher RBC count in case of the professor can be attributed to this acclimatization. Hypoxia enhances the secretion of erythopoetin hormone, which in turn enhances the production of erythrocytes (RBCs) from the bone marrow, thus resulting in increase in RBC count.

b) After returning back from the higher altitudes to the lower altitudes, the number of RBC will return back (i.e. reduce back) to the normal value over some period of time. When the person returns back to lower altitude the RBCs will be present in excess. The excess of RBCs will no longer be required at lower altitudes (in fact they can make blood thicker making it difficult to transport oxygen), so these excess of RBCs are recycled by the reticulo-endothelial system. Moreover, the continuous stimulus (in the form of hypoxia) will also no longer be there for higher eythropoetin secretion, so the elevated levels of RBC synthesis will also not occur.

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.