Hypoxia and Medicine

1) What's the difference between asphyxia and generalized hypoxia? 2) How does hypoxia induce blindness?

Public Comments

1. 1. Asphyxia refers to being unable to get air into the airways, causing a lack of oxygen. Asphyxia can be caused by anything that blocks air, including choking. Hypoxia is the result of oxygen not getting to body tissues and organs, and hypoxia can occur even when air is getting into the lungs if there is another reason that oxygen either isn't getting across the membranes of the lungs into the blood (like in pneumonia) or if the red blood cells are unable to carry it (like in carbon monoxide poisoning). Generalized hypoxia would be a widespread hypoxia affecting the body as a whole and is usually caused by things like altitude sickness in healthy people. Some organs, like the brain, and some areas, like the retina, are exquisitely sensitive to oxygen deprivation. Which leads us to your second questions... 2. Hypoxia can quickly induce blindness because the retina is served by one small artery (logically enough, the retinal artery) and it usually has no alternate or "collateral" supply. Once the cells of the retina die, they can't be replaced, so the person will be blind.