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  • Hey there and welcome to Life Noggin.

  • When you picture allergies, you may imagine someone sneezing, coughing, and itching on

  • a beautiful spring day.

  • Or perhaps you think of someone accidentally eating peanuts or shellfish and going into

  • anaphylactic shock.

  • Whatever the case may be, allergies are a serious problem for many millions of people.

  • But how and why do they develop?

  • And what's so different between allergies to pollen or dust and allergies to bee stings

  • or soy?

  • Well, let's start with what these different types of allergies have in common: your immune

  • system.

  • When an allergen makes contact with a surface on or in your body, nearby immune cells act

  • quickly to destroy the allergen.

  • The cell then covers itself in broken pieces of the allergen and moves to a site of some

  • lymph tissue.

  • When it gets there, it passes pieces of the allergen onto even more immune cells, so that

  • they can work together to form an antibody called immunoglobulin E.

  • If the body comes into contact with the allergen again, these antibodieswhich are proteins

  • designed to attach to foreign substances and remove them from your bodywill start a

  • reaction to fight against it.

  • First they activate a part of the immune system called a mast cell, which then expels a lot

  • of chemicals, like histamines.

  • When histamines are released, they make your capillariesthe smallest blood vessels in

  • your bodymore permeable, which allows white blood cells to enter the capillaries and fight

  • the allergens.

  • However, increased permeability doesn't just let white blood cells in.

  • It also lets fluids out, causing the watery eyes and runny nose that you know and love.

  • And similarly, a congested nose is caused by the capillaries growing larger due to the

  • increased permeability.

  • So that covers how you get allergies.

  • But what about why?

  • Why would your body turn against itself like that?

  • And why are some allergies just annoying while others are deadly?

  • For many years the prevailing idea was that the immune system perceived allergens as being

  • similar to parasitic worms, and for that reason it would unleash the same attack on a peanut

  • as it would on a tapeworm.

  • Parasitic worms are a serious threat, but they are less prevalent than they were in

  • the lives of our ancestors, which explains why Immunoglobulin E would choose to attack

  • allergens in the absence of worms.

  • A similar theory says that allergens may have posed a real threat to us many years ago.

  • According to Dr. Kate Welch, a specialist in immunology and allergies, it's possible

  • that our ancestors were in serious danger when they encountered something like pollen.

  • Therefore, our immune systems are kicked into gear when they make contact with these allergens,

  • even though we evolved and pollen isn't a big threat anymore.

  • Welch claims that it's even possible that allergic reactions are important because they

  • may warn us to get out of a dangerous area, say, directly under a wasp nest.

  • Finally, another theory has come to light recently, and it claims that allergens are

  • actually more dangerous than we might have known.

  • Researchers Ruslan Medzhitov, Noah Palm, and Rachel Rosenstein are at the forefront of

  • allergy research, and they've embraced the new theory.

  • They conducted a study in which they injected mice with an allergen found in bee venom called

  • PLA2, which rips cell membranes apart.

  • They found that immunoglobulin E didn't react to the PLA2—until it started hurting

  • cells.

  • So when you cough or your nose runs, this study suggests that it's just because your

  • immune system is trying to get dangerous allergens out of your body!

  • And when it comes to life-threatening allergies, they're simply a more overactive version

  • of the same response.

  • So don't let your sneezing bother you too much!

  • Your immune system is doing you a big favor.

  • Make sure to come back every Monday for a brand new video.

  • As always, my name is Blocko and this has been Life Noggin.

  • Don't forget to keep on thinking!

Hey there and welcome to Life Noggin.


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アレルギーはあなたの内側に何をしますか? (What Do Allergies Do To Your Insides?)

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    angela770911 に公開 2021 年 01 月 14 日