SciShow host Michael Aranda explains why humans and some species of animal sneeze.
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Why do we sneeze? The long-standing answer has been that sneezing is a reflex. When irritants — such as germs, dust, pollen, animal dander, or pollutants, just to name just a few — infiltrate the nose lining, the brain sends out a signal to get rid of it. That triggers a deep breath, which gets held in the lungs. As a result, the chest muscles tighten and pressure builds. The tongue pushes against the roof of the mouth, forcing breath to come out fast through the nose — Achoo!
Every second of your life you are under attack. Bacteria, viruses, spores and more living stuff wants to enter your body and use its resources for itself. The immune system is a powerful army of cells that fights like a T-Rex on speed and sacrifices itself for your survival. Without it you would die in no time. This sounds simple but the reality is complex, beautiful and just awesome.
If you’ve taken prescription medication, have you ever noticed the strange disclaimer, “don’t take with grapefruit juice”? There is a very good reason for that! Hank Green explains in this episode of SciShow Quick Questions.
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In a recent episode of SciShow, host Hank Green explains why it’s not safe to drink grapefruit juice while taking medication for conditions such as high cholesterol, high blood pressure, and anxiety.
Grapefruit is full of a type of organic compound called furanocoumarin, which interferes with the activity of an enzyme in your small intestine called CYP3A4. Problem is, that interference means your body will absorb more of certain medicines, for things like high cholesterol, high blood pressure, and anxiety, than it’s supposed to. This enzyme’s normal job is to chemically change certain potentially dangerous compounds before they can get to your bloodstream or liver. That way, they’re easier for your body to eliminate. But it also recognizes lots of different medications, and deactivates them the way it would any chemical — meaning that a large amount of the drug you take never actually makes it into your body to do its job.