High school biology was a drag. We live on an incredible planet, but unfortunately the most interesting biology lesson most of us got in school was about sex. Otherwise it was all plant cells, and almost a decade later, I’ve never used my knowledge of photosynthesis.
But biology is one of the most interesting subjects in the world, and there’s so many incredible facts out there you never even thought possible. We all would have gotten much higher grades at school if we’d been taught about them instead of the inner make-up of a leaf!
Here’s 17 of the most unbelievable facts about the human body…
1. The human brain generates enough electricity to power a small bulb
Another amazing fact about the human brain is that it contains a staggering 160,000+ kilometers of blood vessels. It’s no wonder that people lose consciousness 8 to 10 seconds after the blood supply to their brain is stopped.
2. Human teeth are as strong as shark teeth
These apex predators might have the ability to eat us humans, but our teeth are biologically just as strong. Although I doubt my teeth would do me much good if I got into trouble with Jaws. Their strength is beaten by sharks’ razor-sharp teeth!
3. Our stomachs are so acidic they could burn a hole in our skin
To put that in context, our stomachs are so acidic that they could easily dissolve a razorblade. Thankfully, they’re not used for that purpose, and instead our stomach acid helps to keep us protected from harmful bacteria that may enter our bodies with our food.
4. Human hair is practically indestructible
Okay, with the exception of its flammability. Amazingly, there’s enough hair on the average human head to hold the weight of two elephants. But that certainly doesn’t explain why it hurt so much when my sister pulled my hair as a kid…
Our hair also contains a lot of biological information about us, even though it is technically speaking dead. It contains all the information about everything that’s ever been inside our bloodstream, so it’s incredibly useful for forensic analysts.
5. We have the ability to pull 70,000 different facial expressions
Unless, of course, we have had a fair bit of plastic surgery. The picture below shoes what we’d look like if all of the muscles were removed from our faces. It looks like something straight out of a horror movie. Yikes!
6. Babies have 60 more bones than adults
Why? So that their bones can fuse together as they grow. Isn’t biology amazing?! Babies might feel soft and squishy compared to us adults, but that so the birthing process is easier.
7. Our eyes have a resolution of 500 megapixels
Even though cameras are becoming increasingly advanced, those with the highest of resolutions still don’t compare to the human eye because it can do things a camera can’t – like adding in information that would be impossible to pick up digitally. Remember ‘the dress’?!
8. Our skin makes up 16% of our bodyweight
So, as you can imagine, those who undergo dramatic weight loss journeys have the potential to lose even more weight once their excess skin is removed. Biologically speaking, your hair and nails also count as part of your skin.
It’s a common misconception, however, that a person’s nails and hair continue to grow after their mortal coil comes to an end. It simply appears that way because the skin shrinks after death as a result of dehydration.
9. The human skeleton regenerates every 10 years
Why does the skeleton regenerate? Because it, like everything else in the body, is a living tissue. Until the age of 30, our bones continue to grow in density, however, this will decrease as we age unless we live a healthy lifestyle.
10. Our eyes are closed for 10% of the time we are awake
Needless to say, this is the result of blinking. The average person blinks an incredible 28,800 times a day, which is actually a lot more than is necessary to keep their eyes lubricated.
11. Our blood is filtered by our kidneys 25 times per day
That means that 180 liters are filtered every 24 hours. Our bodies are a lot more powerful than what we give them credit for! Whilst it is no secret that you don’t need two kidneys, you actually only need 75% of one to filter your blood.
12. The pink bit in our eyes is a remanent of a third eyelid
If you’re an animal enthusiast, then you might know that birds have a third eyelid – it’s used to keep their vision perfect whilst moistening the eye, so it’s ideal for birds of prey. Amazingly, us humans once had this feature too, but we evolved to no longer need it.
Human eyes are amazing. Whilst they might make us unique, 10,000 years ago everyone had brown eyes, but thanks to a genetic mutation they began to change color. Now eyes can be one or a combination of six colours – amber, blue, brown, gray, green, hazel, or red.
13. The liver can regenerate back to its original size
Providing that there is a minimum of 25% of the organ left. The human body does an amazing job of keeping us healthy and features like this one enable people to save the lives of others through organ donation.
14. Your heartbeat will synchronize to the rhythm of the music you listen to
So that explains why some songs make me want to dance and others make me feel incredibly relaxed. This is why a lot of therapists recommend listening to music as a stress management tool. There’s more to it than just good lyrics!
15. The enzymes that digest our food will eventually digest us
But this will only happen after we die. That’s why many people have their organs removed after death to help preserve their bodies for longer. So the enzymes that you let feast on Big Macs every Friday could eventually be eating you…
16. Our bodies contain atoms that are thousands of year old
Technically, we are all stardust. Isn’t that a wonderful thought? You might feel like the universe is a vast and endless space, and, whilst it is to an extent, us humans have more in common with the night sky than what we might think.
17. The heart will pump 200 million litres of blood around your body in your lifetime
That’s the equivalent of 1.5 million barrels of blood. However, not all humans are the same when it comes to the size of their hearts. The male body contains a heart that weighs 1o ounces, but the female body contains a heart that weighs just eight and that obviously influences its power.
Well, I don’t know about you, but my younger self would have been a lot more interested in biology if I’d been taught these incredible facts at high school. The human body is amazing, and we will no doubt learn even more amazing things about it in the future.