What are secrets of the human body

32 secrets of our body

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Our fingernails grow faster in summer

Sunlight causes the skin to produce vitamin D, which stimulates hair and nails to grow. In Nordic countries or at the Arctic Circle, the nails therefore grow more slowly than in southern regions. In addition, our hands are less well supplied with blood from cold air, which also inhibits nail growth.

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Taste with the nose

Without our nose we couldn't taste anything. While chewing, small amounts of aroma molecules reach the olfactory bulb via the throat. Our nose not only fulfills a filter function for the air we breathe, it is also our air conditioning system and can warm up or cool down the air as required. But this only works with your mouth closed.

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Tooth enamel is more resistant than porcelain

Tooth enamel is the hardest material our body makes. Compared to many other materials such as porcelain, teeth are at best medium-hard. But hardness alone is not everything: teeth are astonishingly damage-resistant, they don't shatter as quickly as other, harder materials.

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It is also possible with only one kidney

Around every 700th person has only one kidney and lives with it just as well as with two kidneys. This is often familial in that babies are born with only one kidney. The second kidney is a kind of back-up solution from evolution just in case, because our kidneys are real workaholics. They filter our blood, help with growth, the regulation of blood pressure and the formation of vitamins.

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Three different types of intestinal flora

Humanity can be divided into three different groups according to the predominant intestinal bacteria. This individual settlement pattern - like the blood group - remains stable for a lifetime. Anyone who takes an antibiotic temporarily destroys the natural intestinal flora.

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Tongue or buttocks - what is our strongest muscle?

For a long time it was said that our tongue is the strongest muscle. But medical professionals have taken a close look at our tongue and found that it cannot keep up with our largest muscle, the gluteus maximus, in our buttocks, our jaw muscles or our heart muscles. But: our tongue is definitely the most flexible muscle! The smallest muscle in the human body is located in the inner ear. It's thinner than a thread.

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Women have bigger brains than men!

It's all a question of relation! At first glance, the male brain is larger than that of a woman, but if you put the size in relation to the body, it turns out that the woman's brain is actually larger. In addition, the halves of the brain are better networked in a woman, and the brain cells live longer than in men.

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Still hungry or full?

This question is decided not in the stomach, but in the brain. Receptors in the liver and stomach tell the pituitary gland how much glucose is in the blood. The hormone leptin gives the brain further information about our fat reserves. It can take up to 20 minutes for the brain to report the "Now I'm full" signal.

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Bitter ear wax drives away insects

Our ear wax provides information about our origins. Europeans and Africans are more likely to have moist ear wax, Asians are more likely to have dry ear dust. Both types of lard, however, do their job: They pack skin flakes, hairs and dirt and transport the mixture out of the ear canal to the outside. The bitter taste and smell prevent small insects from entering the ear canal.

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And yawning is contagious!

Our mirror neurons are to blame: If we recognize how our counterpart is feeling, then we automatically feel similar. That is why we can laugh with them, weep with them or mourn with someone. This behavioral program is innate. It also turns on when you yawn: When we see someone yawn, we usually have to yawn too. By the way: lack of oxygen in the brain does not make us yawn - but tiredness and boredom!

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And how many spleens do you have?

Every fourth person has, in addition to their "main spleen", another or even several secondary spleens. These are usually meaningless. If the main spleen is affected by an accident, for example, the secondary spleens become active. By the way: In babies, the blood cells are still formed in the spleen; the bone marrow only takes on this function later.

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Regrowing liver

No other organ can do this: If parts of the liver have to be removed during an operation, they can grow back in a few weeks if the remaining liver cells are otherwise healthy.

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Auricles grow for a lifetime

Even if our body size shrinks with advanced years, our auricles grow until the end of life. Researchers suspect that this is how we compensate for part of the hearing loss in old age.

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Hormones determine the length of the fingers

In men, the ring finger is usually longer than the index finger - in women it is exactly the opposite. This is due to the influence of male and female hormones on the unborn child. In men, the ring fingers are usually around four percent longer than the index finger.

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Sweat doesn't smell like anything

The fluid that our sweat glands produce to cool the surface of the body is odorless. Only bacteria, which prefer to sit on the skin in the armpits, make the sweat smelly through decomposition processes.

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The appendix is ​​not superfluous

The supposedly useless appendix houses helpful intestinal bacteria. In the past, the now stunted organ probably served as a kind of fermentation chamber for plant-based food that would otherwise have been difficult to digest.

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Muscular ears

The remnants of our millions of years of development to modern humans also include the numerous ear muscles, which once made the ears movable in all spatial directions, as well as the wisdom teeth and our pointed canines.

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Superfluous organs?

None of our organs are really useless. But a number of them are not essential. For example, we can continue to live without a stomach, spleen, appendix or gallbladder. A lung and a kidney can also be dispensed with to a certain extent.

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Hairy like a chimpanzee

Humans have almost as much hair as chimpanzees and other great apes. However, our body hair is much finer and lighter than that of our closest relatives. From a zoological perspective, we also count among the primates.

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Mites live in the eyelashes

The older we get, the more eyelash mites populate our eyelids. The mites are actually harmless sub-tenants (commensals), only a few people are allergic to the lid inhabitants.

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We do not tan on the palms or soles of the feet

Melanin-producing cells are missing in these parts of the body, which prevents tanning from the sun's UV radiation. Sun protection is particularly important here.

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We don't have five, but six or even seven senses

The sixth sense is a so-called meta-sense. It allows you to hit the tip of your nose with your finger with your eyes closed. The seventh sense, on the other hand, was only recently discovered. It enables us to anticipate exceptional situations shortly beforehand.

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Not all tears are created equal

Joy, anger, sadness - or just onions: whatever reason we cry makes a difference in the structure of our tear fluid. This was the finding of an American photographer who took pictures of tears at a hundred times magnification. By the way, our tears also act as a defense: the enzyme lysozyme contained in it destroys the cell wall of bacteria, rendering the germs harmless. And one more fact about tears: on average, every person cries a bathtub in the course of their life.

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Iron stains the blood red

Not true, the red color is due to the blood pigment hemoglobin. By the way: the more oxygen there is, the lighter the color of the blood.

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Adrenaline gives you wings

The mother who defends her baby down to the blood or the thin man who can suddenly stand up to thugs: In need, people develop bear strength. In tricky situations, the stress hormone adrenaline ensures that we can run faster or hit harder for a short time and are more concentrated. Our heartbeat is accelerated and the energy supply to the digestive organs is reduced in favor of the muscles.

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Tell-tale pupils

Whether it's a pretty colleague or a three-tier cake: if we find someone or something attractive, our pupils dilate by up to 50 percent.

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More bacteria than cells ...

... make up our body. The ratio is about ten to one. Most of the bacteria that we harbor are important for health and ensure, for example, a balanced intestinal flora. The totality of germs that our body harbors is called the microbiome. It will take years to decipher it.

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Stool is almost entirely water

Our feces also consist partly of disused intestinal bacteria. The majority of the "big business" is made up of around three quarters of the water. The rest are dyes, intestinal cells and indigestible food residues.

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Breathe or swallow?

We have to decide: grown-ups cannot do both at the same time. As babies we still have this ability, but we lose it over the course of the first nine months of life.

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Goosebumps come from the cold

That's true, but fear and aggression also pull the skin together. The hairs on the body stand up as a result: ancient times with thick fur, this looked threatening to the opponent.

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More arithmetic than seeing

When seeing, the brain adds image details that our eyes do not provide at all. This is exactly why we fall so easily on optical illusions.

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