BIZARRE: Doctors share dumbest patients | Mind Blowing Facts

We spend so much time taking care of our bodies, yet there’s still an incredible amount we don’t know about what’s happening beneath the surface. For instance, most of us know that an adult human skeleton has 206 bones, but did you know that babies are born with around 300 bones? As they grow, some of those bones gradually fuse together, eventually forming the 206 bones found in the typical adult skeleton. These bones are divided into two main groups: the axial skeleton, which contains 80 bones and forms the central axis of the body, including the skull, spine, ribs, and sternum, and the appendicular skeleton, which contains 126 bones in the shoulders, arms, hands, pelvis, legs, and feet. 

Interestingly, even some basic facts about our bodies aren't as well known as you might expect. A USANA-sponsored survey of 2,000 Americans conducted through OnePoll found that 35% of respondents didn't know their own blood type. The survey also found that only about one in 10 people knew that O-negative is considered the universal red-blood-cell donor type, while just one quarter correctly identified the four main blood groups: A, B, AB, and O. Knowing your blood type can be useful information, particularly when it comes to blood donation, pregnancy care, and medical situations. Of course, hospitals still test and confirm a person's blood type before giving a transfusion, but knowing your own can certainly be helpful when you're trying to understand your health.

And sometimes, the best way to appreciate just how fascinating the human body is is to look at it from a completely different perspective. That’s exactly what Bill Bryson does in The Body: A Guide for Occupants, a lively and often funny exploration of how our bodies work and what makes them so remarkable. The book is packed with fascinating, mind-boggling, and occasionally gross facts about human biology, including one particularly fun question: How much would it actually cost to build a human being from scratch? Citing a Royal Society of Chemistry calculation, Bryson notes that the 59 elements needed to construct a human body, using Benedict Cumberbatch as the example, would cost around $151,578. Of course, that price only reflects the estimated value of the raw elements—not the rather more complicated task of turning them into a living, breathing human being.

And the more you learn about the human body, the more you realize that even some of our most familiar sensations are not quite as straightforward as they seem. We cannot actually feel wetness directly. Human skin doesn't have specific receptors dedicated to detecting “wetness.” Instead, researchers believe that the brain works out that something is wet by combining other sensory information, particularly changes in temperature and mechanical sensations on the skin. That's why water can feel wet even though your skin is really detecting a combination of different signals. In other words, that familiar sensation of being wet is partly your brain making sense of the information your skin is sending it. Pretty impressive, considering how effortlessly we experience it every day.

When you zoom out from how the body experiences the world to what it's actually made of, the answer is surprisingly simple. You might not have enjoyed studying the periodic table at school, but those chemical elements are literally what make you, you. Just six elements—carbon, hydrogen, oxygen, nitrogen, calcium, and phosphorus—account for roughly 99% of the human body's mass. Oxygen and hydrogen are especially abundant because the body contains a large amount of water, while carbon forms the backbone of many of the molecules that make up our cells and tissues. Nitrogen is essential for proteins and DNA, while calcium and phosphorus are particularly important for bones and teeth. So, despite being an incredibly complicated biological system, the human body is built largely from a surprisingly small collection of elements.

We use the internet every day and are used to information traveling almost instantly, but our own bodies have an impressive communication network too. Nerve signals can travel at speeds of around 120 meters per second, or roughly 430 km/h, in the fastest myelinated human nerve fibers. These electrical signals allow your brain and body to communicate incredibly quickly, helping you move, react to danger, feel sensations, and coordinate everything from walking to picking up a cup of coffee. So while your Wi-Fi connection might occasionally let you down, your nervous system has been running its own high-speed communication network inside you all along.