Snot, you perplexing green goop, you smell-stopping slime that oozes forth from my face, what secrets do you hide? What message, o poor sick body, who do you telegraph me through this globby gak?
The usual snot runs clear, acting as a lubricant and the body's first line of defence against viral and bacterial invaders. The nose's so-called goblet cells produce proteins called mucins that link into chains, with sugars at their tips to help absorb water. Mucous is 95 per cent water, in fact, while crusty boogers are simply snot sans moisture. A healthy individual makes a half a cup of snot per day, and swallows almost all of it.
Bacteria-destroying enzymes called lysozymes and white blood cell-beckoning antibodies live inside the goop to kill any intruders. But first line defences can fail.
An allergic response might cause white blood cells to release histamines, signalling blood flow to the nose and causing your snot to run. An infection also sends blood to the nose, causing inflammation and a stuffy, congested feeling. Mucus could even pool in the sinus cavities, the air pockets in your face's bone structure, building up pressure and triggering headaches.
But snot doesn't just get in the way when you're sick — it plays an active role in helping you get better. First, the slime helps to trap and fight teeny terrors. White blood cells might join the fight, thickening the mucus and turning it white and opaque. And if your mucus has turned green, that means immune cells called neutrophils have released myeloperoxidase, an acid-producing enzyme that aids in bacterial slaughter. If your sick snot is red, that's blood, so stop picking or blowing your nose for a while.
Different medicines loosen up your nose's mucus in different ways. Decongestants squeeze blood vessels in the nose, reducing inflammation by restricting the blood supply. Anithistamines, meanwhile, block the body's histamines that signal for a runny response.
Incredible snot, who knew you were so wonderful. Thank you for keeping me safe from the meanest of microbes, and keep on stuffing my nose so that I may stay healthy.