Jill lives in St. Louis, which is close to sea level. She decides to spend a month of her summer vacation working in the mountai
ns outside of Denver. After a week in the mountains, what kinds of changes would you expect to see as Jill adapts to the higher altitude? A) decreased hematocritB) decreased blood pressureC) decreased alveolar ventilation rateD) decreased PO2 in the alveoliE) All of the answers are correct.
High altitude is a challenge for the human body due to the progressive reduction in barometric pressure leading to series of important physiologic responses that enable individuals to adapt and secure the oxygen supply to tissues. Reduction in oxygen pressure causes physiological responses in body which include increase in hematocrit. Also, the development of systemic hypertension is influenced by high altitude due to relative low oxygen which has significant consequences on the cardiovascular system and on blood pressure regulation. The lung response to acute altitude exposure also includes hyperventilation which aims at achieving adequate supply of oxygen to the tissues.
Therefore, regular oxygen uptake, greater ventilation, more basic hypoxic ventilation, larger lung volumes, greater diffusing capacities and increased blood pressure are typical of Jill as he adapts to the higher altitude after a month.
Due to their immense oxygen needs, slow-twitch fibers are associated with many blood vessels, mitochondria, and increased concentrations of myoglobin, an oxygen-binding protein in the blood that provides muscles their reddish coloring.
