Say you need to get a bunch of your friends—more than a quintillion of them, in fact—from one place to another to do an important job. Naturally, you’re going to need a creative way to get them there. Would you use a plane, train, or car? Maybe you’d need all of the above! This is exactly what the respiratory system does: it gets oxygen from the air, through the body, and all the way to the tissues to help the cells make energy from the food you eat. Then it needs to send the cells’ waste—carbon dioxide—out of the body. We call this process gas exchange. Fortunately, it gets a hand from your circulatory system and several clever modes of transportation to get the job done.
We can't see it, and usually can't smell it...but have you ever thought about the air you breathe? What's it made of, anyway? Is all air created equal?
The lungs are the central organs of the respiratory system. They play a vital role in a wide variety of critical bodily functions that keep you alive and healthy. For example, the lungs, assisted by muscles of respiration like the diaphragm (located below the lungs) and the intercostal muscles (found between the ribs), are responsible for the body’s ability to breathe.
When an allergen enters your respiratory system, it can set off a false alarm that causes your immune system to mistake it for an invader. Recall from Adv. 6 that your immune system responds to viral invaders by creating antibodies[note for web design: link to Adv. 6materials]. The immune system does just that - it forms antibodies to fight the allergen, even though it’s harmless. Each time you encounter the allergen thereafter, the new antibodies alert the immune system, which responds by releasing histamine (Say it like this: HI-stuh-meen).Histamine is a hormone, and we remember from Adv. 8 what they do[note for web design: link to Adv. 8 materials]- they tell your cells to do stuff! In this case, they tell your cells to sneeze, cough, irritate your eyes, or make your nose run.