The amount of available oxygen in a breath has limits on the upper and lower ends. Oxygen toxicity can begin to set in at roughly 1.6 ata or at the surface at concentrations of 100% over protracted periods. At a lower concentrations where hypoxia sets in (may be enough molecules available to sustain life at depth i.e. higher partial pressure, but when surfacing the concentration will drop allowing hypoxia to set in) I can't remember the bottom limit. Even though at depth, more oxygen molecules are available in each breath, the limiting factor is the binding sites on the hemoglobin proteins within the red blood cells. These receptors have a finite limit to the amount of oxygen that can be carried. With more oxygen molecules (e.g. a higher oxygen partial pressure), more oxygen can diffuse into the blood, but only so much of it can be carried to the cells by the hemoglobin.
People who live in higher altitudes have acclimated to the lower available oxygen by having higher hemoglobin counts.
Hypoxia with non-acclimated people at altitude occurs because less oxygen (concentration) is available with each breath and the receptors are not filled, so less oxygen is available for metabolism.
Higher concentrations of oxygen are given to DCS victims when they are treated do to the affect of dropping the nitrogen partial pressure and therefor allowing it to diffuse out of the cellular tissue and blood to be outgassed by the lungs.
That was your Biology 101 lesson for today.
People who live in higher altitudes have acclimated to the lower available oxygen by having higher hemoglobin counts.
Hypoxia with non-acclimated people at altitude occurs because less oxygen (concentration) is available with each breath and the receptors are not filled, so less oxygen is available for metabolism.
Higher concentrations of oxygen are given to DCS victims when they are treated do to the affect of dropping the nitrogen partial pressure and therefor allowing it to diffuse out of the cellular tissue and blood to be outgassed by the lungs.
That was your Biology 101 lesson for today.