Natural acclimatization in high altitude is due to
(Decreased oxygen level): (650-Ganong-24th edition, 488-89- A.KJain 5th, 529-30- Guyton 12th)* Hypoxia in permanent residents at high altitude is called "acclimatization" at high altitude* Mechanism|Arterial pO2|Stimulate peripheral chemoreceptors||Pulmonary ventilation|CO2 washout|l Alveolar pCO2|||H+ concentration in blood (Alkalosis) and this should inhibit the respiration Differences between 'High Altitude Native' and Newcomer to High Altitude1. Increase in pulmonary ventilationMore therefore(a) Chest become enlarged (barrel shape)(b) Alveolar ventilation is more(c) FRC is moreLess therefore(a) Chest is smaller in size(b) Alveolar ventilation is less(c) FRC is less2. Response to hypoxic stimulationMore, therefore, hypocapenic alkalosis is lessLess3. Urine reactionAlkalineAcidic4. Affinity of haemoglobin for O2Less, therefore, more O2 is released from haemoglobinMore , therefore body tissue suffers from hypoxia,5. RBC countHigher, therefore PCV increases,Because of polycythemia, these individuals have red cheeksLow6. Organ vascularityMoreLess7. Mitochondria and myoglobin content of muscleHighLow8. Diffusion capacity of lung for O2MoreLess
Increased ventilation
Increased oxygen utilization
Increase the chest size and decrease the abdominal circumference/accommodate
Decreased oxygen level
Respiratory System