Everyday Biology: Did You Know? – Part 3

[B] Goiter | Without iodine your thyroid balloons like it’s trying to suck the last drop out of your blood. That’s why table salt got iodized—no one wants a neck puffball.

[C] Allergies | They tell your immune system to chill about pollen. Basically a “relax, it’s just grass” pill.

[A] Vitamin K | Got its name from the German word for clotting. Babies get a shot at birth ’cause they show up low on glue.

[C] Leukemia | White cells copy-paste like crazy until the blood’s mostly useless copies—immune cells that can’t immune.

[B] Tendons | Stronger than steel cable ounce for ounce. Your Achilles can take 1,000 lb—just don’t piss off any archers.

[D] Fungus | Not a worm, just a fungus that draws circles on your skin. Medieval docs named it and we’re still stuck with the typo.

[A] Chromosomes | Stretch your DNA out and it’s six feet long. Chromosomes fold that blueprint into microscopic suitcase squares.

[A] Hemoglobin | Means “sea blood” because it first showed up around the Mediterranean—genetic proof evolution sometimes ships a beta version.

[B] Night blindness | You need A to crank out rhodopsin, the dim-light protein. Without it, sundown = temporary blackout till breakfast.

[D] Pituitary | Sits in a tiny skull office calling the shots for most other glands—basically your body’s hormonal middle manager.

[B] Bones | Bones stash 99 % of your calcium like a 401(k). When blood levels dip, they crack open the vault—no ATM fees.

[D] Keratin | Same stuff in rhino horns & bird beaks. Your nails grow 0.1 mm a day—rhino power in slo-mo.

[A] Double helix | Twisted ladder that spells “you.” Watson & Crick snapped the photo; Rosalind Franklin took the real pic.

[B] Neurons | 86 B cells, 100 T connections—more links than 1 000 Milky Ways crammed into a 3-lb blob.

[C] Anemia | 2 B people run watered-down blood—oxygen delivery at dial-up speed.

[A] Leukocytes | Five-branch army that eats invaders and keeps receipts for decades.

[C] Oxygenated | Except the pulmonary artery—the rebel that ships blue blood to the lungs. Biology loves exceptions.

[D] Insulin | 1921 dog-pancreas extract turned a death sentence into a daily shot—first diabetes hack in history.

[B] Dermis | 3 million glands crank up to 3 gal/day—your built-in A/C with no off switch.

[D] Brain | 2 % of body weight, 20 % of your calories—basically a hungry, wrinkly electrical potato.

[B] Bone marrow | Cranks out 2 million red cells per second—your body’s Prime Day that never ends.

[A] Rickets | Turns legs into overcooked spaghetti; Victorian smog blocked so much sun that bow-shaped kids were basically normal.

[C] Anatomy | From Greek for “slice open.” Ancient pros were corpse-dismantling artists with really good pencils.

[B] Fluorine | Fluoride hardens enamel like steel. When cities fluoridated water, dentists’ wallets lost 25 %—but kids kept their teeth.

[B] Nostrils | They take shifts—every few hours one’s boss, the other’s on break. You’re a one-nose-breather and never notice.

[C] Malacophily | Slime-trail flower delivery—slowest courier service ever, but evolution said “I’ll take it.”

[A] 33 | Some later fuse, so you shrink with age—Grandpa really was taller back in the day.

[C] Wilhelm Johannsen | Coined it in 1909 from Greek “birth.” Before that, scientists just pointed at heredity and mumbled “stuff.”

[D] Biogeography | Explains why kangaroos skip Australia-only and why island creatures are gloriously weird—isolation makes evolution drunk-creative.

[A] Iron | Every red cell packs 280 million hemoglobin molecules, each with a tiny iron hub. You’re basically 4 grams of rust pretending to be human.

[D] Paleontology | CSI for creatures that turned into rocks—except the victims died 65 million years ago.

[B] Endocrine | Texts travel at 2 mph through blood—snail mail compared to nerves, but the message sticks around.

[D] Liver | Packs ~100 g of glycogen—enough juice for a 10-mile jog. Your built-in snack vending machine.

[C] 7.40 | Has to stay 7.35-7.45 or you’re toast. Lungs & kidneys work overtime like micro-managers to keep that digit alive.

[C] Cerebral cortex | Motor map is upside-down with supersized thumb real estate—your brain thinks hands beat backs.

[D] Elephantiasis | Worms clog lymph pipes → fluid piles up. Legs become walking waterbeds nobody wants to bounce on.

[D] 206 | You start at 300, fuse down to 206. Lose 94 bones growing up—no tooth-fairy cash for those.

[C] Aorta | Inch-wide candy-cane hose that handles fire-hydrant pressure. Candy cane shape, candy consequences.

[A] Cognitive biology | Asks “what were they thinking?” with microscopes, not gossip.

[A] Balloon | Thyroid needs only 150 µg/day—less than a grain of sand—but without it your neck puffs like a parade float.