Final answer:
A decrease in the percent of oxygen in the air results in decreased oxygen saturation of hemoglobin, leading to hypoxia and associated symptoms. The body tries to compensate by increasing hemoglobin production. The oxygen-hemoglobin dissociation curve also helps regulate oxygen delivery to different tissues based on their metabolic needs.
Step-by-step explanation:
When the percent of oxygen in the air decreases, there can be substantial impacts on the body's ability to move oxygen to where it is needed. Normally, oxygen binds reversibly with hemoglobin in the red blood cells which facilitates its transport from the lungs to various tissues.
A lower concentration of oxygen in the environment can lead to decreased oxygen saturation of hemoglobin, resulting in hypoxia—insufficient oxygen reaching the body tissues. This can cause symptoms like fatigue, headache, and confusion, and in more severe cases can impair coordination and judgment, primarily at high altitudes or with rapid changes in oxygen levels.
The body compensates for low oxygen concentrations by increasing the production of hemoglobin, as seen in people acclimatized to high altitudes. However, this adaptation takes time, and rapid changes can be detrimental. Furthermore, synthetic oxygen carriers have been designed to maintain oxygen levels in the bloodstream during emergencies as they possess high Henry's law constants for O₂, thus ensuring comparable dissolved oxygen concentrations to normal blood.
Furthermore, the body has regulatory mechanisms, such as the oxygen-hemoglobin saturation/dissociation curve, that control oxygen delivery to tissues based on their metabolic rate. For example, active tissues like muscles will have a lower partial pressure of oxygen, causing more oxygen to dissociate from hemoglobin and fulfill the tissue's needs, while less active tissues will retain higher oxygen levels, and thus fewer oxygen molecules will dissociate from the hemoglobin.