Back To CoursePathophysiology Textbook
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When you were a little kid playing around in the pool, you probably engaged in all sorts of fun stuff with your friends, ranging from going down the slide to cannon-balling in from the diving board.
One other thing you may have done is held your breath underwater to see who could do it the longest. Most likely, you didn't manage to do so for more than a couple of minutes. That's kind of puny when compared to the world record of over 11 minutes without the aid of pre-breathing 100% oxygen.
But, oxygen deprivation is never a good thing, even for short periods of time, as this lesson will explore using various terms related to this problem.
Before I begin to go over why oxygen deficiency is so bad for you, we need to explore a few terms that deal with this topic.
One of these words is known as hypoxia, which is a term that describes an inadequate amount of oxygen supply or utilization in a region of, or the entire, body. This is a less extreme form of improper supply of oxygen than anoxia, which is the complete lack of supply to or utilization of oxygen to parts of the body or the entire body.
The reasons why hypoxia may occur are many. For example, one cause of hypoxia is ischemia, or the inadequate supply of blood to a tissue or organ, due to obstructed or constricted vasculature, resulting in an inadequate supply of oxygen.
You can liken the vasculature to one of those water slides at the pool. The water flowing down the slide is like the blood, and the round floats are the red blood cells that carry a person, or oxygen, to the pool, or body tissue.
If the water slide is obstructed by something or gets narrower, then the water won't be able to get through as well, the round floats will get stuck, and the person won't make it to the pool. All of this results in improper delivery of oxygen to an organ or tissue, causing hypoxia.
Real-world reasons for ischemia include atherosclerosis, where fatty buildup in arterial walls obstructs or narrows down blood vessels, blood clots, and much more.
Another reason for hypoxia is anemia. Anemia is an inadequate amount of healthy red blood cells. Anemia can occur due to three main reasons: destruction of red blood cells, not enough production of red blood cells by the body, or loss of red blood cells through bleeding.
Since you know that red blood cells carry oxygen, then obviously not having enough red blood cells, due to any reason, means there aren't enough round floats to carry enough people around on our water slide. This means that fewer people get down the slide and into the pool, resulting in oxygen deficiency at the tissue site.
There are plenty of other reasons as to why a lack of oxygen in the body may occur, even if there are plenty of red blood cells and the blood vessels aren't obstructed.
You've probably heard of one of those reasons: carbon monoxide poisoning. The reason this occurs is as follows. Your red blood cells contain a little protein called hemoglobin that has four oxygen binding sites. Meaning, it can carry four oxygen molecules. Once it grabs onto four oxygen molecules in your lungs, it will let them go once it nears an organ in your body that needs it.
The problem is that if you start inhaling carbon monoxide, the carbon monoxide will bind to hemoglobin far more tightly than it would to oxygen, and in preference to oxygen as well. Meaning, carbon monoxide molecules, which cannot be utilized by your body, out-compete oxygen molecules for the hemoglobin-binding sites.
Furthermore, the carbon monoxide also causes the remaining binding sites on hemoglobin to bind any oxygen molecules far more strongly than before. This increased strength in the binding of oxygen to hemoglobin means that as soon as the red blood cells near an organ that needs oxygen, the hemoglobin proteins cannot let the oxygen go. Therefore, even though there is plenty of oxygen in the blood, none of it can actually be delivered to the tissues and organs that need it.
It's as if your local delivery man drives his truck up to your house, leaves his truck with a package in hand, but doesn't actually want to let the package go. Therefore, you never get the package delivered to your front door even though the delivery man was right there, package in hand. That's what happens in carbon monoxide poisoning.
Another type of poison that can cause hypoxia is called cyanide. In this case, cyanide doesn't stop the delivery of oxygen to tissues, like carbon monoxide does. Instead, cyanide inactivates an enzyme called cytochrome oxidase within the cells of tissues. The inactivation of this enzyme renders the cells in our body's tissues and organs incapable of using oxygen for energy production, resulting in their death. Therefore, oxygen delivery to tissues in cyanide poisoning is not impaired; it is the utilization of the delivered oxygen that is compromised. In any case, this results in hypoxia.
Regardless of whether there isn't enough oxygen in the air to breathe, there's improper supply of oxygen via blood vessels, inadequate release due to carbon monoxide, or improper utilization due to cyanide toxicity - whatever the case may be - cells in your body, especially those of the brain, kidneys, and heart, begin to suffer and die when they do not receive enough oxygen, since they need an oxygen supply for energy production. Without energy, the cell simply dies.
You'd think that if a person were to undergo severe hypoxia that you'd want to restore blood supply and oxygen supply to the affected and dying tissue as soon as possible. While we used to think that was the case, we now know we need to avoid something known as reperfusion injury. In short, what happens is as follows. As soon as blood supply and oxygen supply is restored to a dying tissue after severe or prolonged hypoxia, an inflammatory response begins, which results in the generation of free radicals. The inflammatory process in and of itself, along with the dangerous free radicals, begins to actually damage the affected tissues and organs even more.
As you can tell, the reasons for hypoxia are many, and all of them are dangerous.
Hypoxia is a term that describes inadequate amounts of oxygen supply or utilization in a region of the body or the entire body. This is a less extreme form of improper supply of oxygen than anoxia, which is the complete lack of supply to or utilization of oxygen to part of the body or the entire body.
One reason for hypoxia is ischemia, or the inadequate supply of blood to a tissue or organ, due to obstructed or constricted vasculature, resulting in an inadequate supply of oxygen.
Another reason for hypoxia is anemia. Anemia is an inadequate amount of healthy red blood cells.
There are plenty more reasons for hypoxia, including carbon monoxide and cyanide toxicity.
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Back To CoursePathophysiology Textbook
20 chapters | 274 lessons