Question: How Do Tibetans Survive at High Altitudes? Need Assignment Help?
Adapted From Understanding Evolution; Berkeley If you live in the lowlands, you may have experienced the huffing and puffing that typically accompany a trip to higher altitudes. That's because oxygen levels go down as one goes up. Traveling to Denver from sea level means a 17% decrease in available oxygen. Our bodies compensate for even this small change with faster breathing and a higher heart rate - at least until we acclimate to the thinner atmosphere. What happens when you travel to the mountains? As you increase elevation the PO2 in the air drops which affects the pressure in arterial blood (PAO2). The brain detects these changes and sends a message to increase respiration rate, a condition called hyperventilation. You are likely to take deeper breaths in addition to breathing faster and your heart rate will increase. You may experience dizziness, nausea, fatigue, and headaches. Low arterial PO2 will cause the release of erythropoietin from the kidneys. EPO will stimulate the bone marrow to produce more red blood cells to increase the concentration of hemoglobin in the blood. This hemoglobin will have the effect of providing tissues with more oxygen. Extra hemoglobin may compensate for decreased oxygen levels, allowing breathing and heart rate to return to normal. This is an example of phenotypic plasticity, shifts in an organism's body, physiology, or behavior that are dependent upon the environment