Welcome, Know Yourselfers, to our twelfth and final adventure! It’s been a long ride, but here we stand at the integumentary system -- the perfect one to wrap it all up! As I’m sure you know by now, the integumentary system consists of your skin, hair, and nails, and I’d be happy to shed some light. It’s a big system, which leaves a lot of unanswered questions, but never fear, Dr. Bonafide is here to give you the skin-ny! I said give you the skinny -- did you hair me? Ha ha ha...nailed it!

The best games are the ones where you are moving your body. Not only are they entertaining, but they’re also extremely healthy. One of the best things you can do for your health is to move your body as much as possible, so we want you to get some fresh air and get moving with some fun activities. . This isn’t all fun and games, though - we also want you to understand what is going on in your body while exercising.

Are you afraid of spiders? Many of us are, and when confronted with one, we’ll have one of two responses - the first is fight- to spring into action and show that spider who runs the jungle. The second is flight- to run away in fear. This human response to perceived threats is aptly named the fight-or-flight response, and is the result of an interaction between our brain and endocrine system, an interaction called the - you ready? - hypothalamic-pituitary-adrenal axis*. For brevity’s sake, we call it the HPA axis.

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.

You’re sweating, flushed, nauseous, and fumbling for words...is the flu coming on? No, it’s just time to talk about the “P” word: puberty. Are you worrying about how to bring up the topic with your pre-teen? It can be an awkward subject for both parents and kids, but understanding the science of what’s happening can help to put everyone at ease.

You have over 600 muscles in your body. So many, in fact, that muscle makes up about half your weight. It may seem muscles take up more than their fair share, but they have good reason to make such a heavy claim to your frame: muscles are your body’s primary source of power. Whenever something inside you needs to move, chances are your muscles make it happen.

A muscle sprain or strain may sideline you to the couch. But while you’re resting up, do you ever wonder...what are my muscles doing right now? Your body has some clever gadgets to help you heal. While you’re catching up with your favorite show or re-reading a book, your muscles are calling on their own in-house repair team, which is always waiting in reserve to help you out in a pinch (or sprain).

Hello, Adventurers! Dr. B here again, ready to answer all of your burning questions. Speaking of feeling the burn, today we’re talking about sore muscles. We’re told, “No pain, no gain,” but do you ever wonder what causes the tenderness in your triceps, the fatigue in your forearms, or the cramp in your calves after a day of hard exercise? Fortunately, I have a  tendon-cy  to know these things! Read on to learn why some of your most helpful body parts can make you feel so miserable

Hello to all you adventure boos and ghouls! It’s your skeleton friend, Dr. Bonyfide, ready to answer all your eerie inquiries. As I’m sure you’ve noticed, autumn is upon us, and this round of questioning falls on Halloween! In the spirit of the season, you sent in a bunch of creepy  questions -- I never knew you s-cared so much! -- but I could only answer three, and it was tough to decide...witch.

When it comes to anatomy, you’re nearly an expert on knowing yourself by now. But can you apply what you’ve learned to something a little less…human? Think like a mad scientist and help us collect as many field notes and observations about zombies compared to us humans!