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Stubbing Your Toe Hurts So Much Because It's Attacking A Bunch Of Nerves At Once
There's no pain quite like twanging your funny bone or stubbing your toe. Which is weird when you think about it, considering that one of those parts is made of pure bone, while the other was put there by evolution to make your flaming spin-kicks even more devastating. By all rights, they should be some of the hardiest parts on the emaciated flesh bag that you call a body. So why aren't they?
It comes down to nerves. Your toes, for instance, are packed with nerve endings known as nociceptors, which are responsible for creating the feeling of pain. Those suckers are everywhere, but unlike the rest of the body, your toes aren't well-padded. Which means that any hit to your toes triggers an apocalyptic pain reaction.
Dr. Joseph Volker/Earth's LabIt's an intricate system highly evolved enough to alert you to any danger, but not evolved enough to keep from constantly slamming into the coffee table.
There's also the fact that your brain is hardwired to read pain differently depending on the body part the signals are coming from. Your brain isn't bothered much by the pain notifications it receives from, say, your hips or breasts compared to how over-the-top it gets when it thinks your hands, tongue, or feet (and the rest of the ways you receive sensory data) are under attack.
This might sound like an unfair way of doing things, but it makes sense from an evolutionary perspective. One of the main ways we explore the world, after all, is through walking. If our feet weren't fine-tuned to react oh-so dramatically to injury, then that might lead to us taking a more laissez-faire response to injuries, leading in turn to an increased risk of infection and, inevitably, an increased risk of our species dying out. We'll let you judge whether that's a bad outcome or not.
Likewise, your funny bone is extra-sensitive to the slightest injury because it's basically an obstacle on the nerve superhighway connecting your hands to your brain, otherwise known as the ulnar nerve. This nerve is well-protected along the majority of its length, but when it gets to your elbow, it has to pass by a bone knob (stop giggling) called the medial epicondyle. And like with your toes, this section of elbow doesn't have any padding. When you bang your funny bone, that means your arm is at just the right angle to pin your exposed nerve against the medial epicondyle, resulting in one helluva mental noogie.
4
Latchkey Incontinence Is The Reason You Need To Pee When Arriving Home
You're pretty good at holding it in. You're all grown up now, you're in big person undies. And yet incontinence threatens to strike as soon you pull up the driveway or step into your building. Your inner workings become so sensitive that the slightest knock could result in an explosion that takes out your pants, your dignity, and two city blocks. It's not your fault, though. It's the work of latchkey incontinence -- a bizarre psychological phenomenon typified by "loss of urine that occurs when one arrives home and puts the key in the lock of one's front door." You know, on the off chance that the phrase "latchkey incontinence" wasn't obvious enough.