8 surprising facts about the human body that do not fit in your head

1. The body makes alcohol

In our body there isA. G. Antoshechkin. On Intracellular Formation Of Ethanol And Its Possible Role In Energy Metabolism / Alcohol and Alcoholism; A medicolegal approach to the very rare Auto-Brewery (endogenous alcohol fermentation) syndrome / Traffic Injury Prevention; Vyacheslav Dubynin. Brain and alcohol ethanol, even if we're completely sober. It is produced in the gastrointestinal tract as a result of the digestion of food by the microorganisms living there. In addition, some ethanol is produced during the processing of glucose in cells.

This byproduct of the body's life is called endogenous alcohol. Its amount in the blood usually does not exceed 0.18 ppm, so most often ethanol does not intoxicate. But there are also exceptions.

There is a rare diseaseK. Painter, B. J. Cordell, K. L. Sticco. Auto-brewery Syndrome / StatPearls; B. Cordell, J. McCarthy. A Case Study of Gut Fermentation Syndrome (Auto-Brewery) with Saccharomyces cerevisiae as the Causative Organism / International Journal of Clinical Medicine called autobrewery syndrome (otherwise called fermentation bowel syndrome or endogenous ethanol fermentation), when the body produces more alcohol than it needs. This happens if bacteria and fungi living in the digestive system have multiplied and began to allow themselves more than usual.

In fact, there is nothing pleasant about this, since people suffering from this syndrome cannot control the production of ethanol and experience everything on themselves. detrimental influence drunkenness. They have headaches, cannot concentrate and even become aggressive.

And in one woman in the United States, ethanol began to be produced altogether.K. M. Kruckenberg, A. F. DiMartini, J. A. Rymer, A. W. Pasculle, K. Tamama. Urinary Auto-brewery Syndrome: A Case Report / ACP Journal... in the bladder. Due to the yeast colony that settled there, her urine began to ferment and smell like alcohol. And then the American generally developed cirrhosis of the liver, although she had never drunk in her life.

The disease is being treatedK. Painter, B. J. Cordell, K. L. Sticco. Auto-brewery Syndrome / StatPearls antibiotics and antifungal agents. Then a course of probiotics is prescribed to normalize the bacterial balance in the body, and it is recommended to adhere to a diet that contains less sugar and carbohydrates and more protein.

2. Human lungs are extremely wide

It would seem that people are quite compact creatures. Still, we are far from elephants, giraffes and blue whales. But in fact, the human body can impress with its numerical indicators.

For example, our lungs contain about 600-700 million tiny vesicles, or alveoliLungs / Great Russian Encyclopediathat suck oxygen from the inhaled air. The alveoli are covered with a special breathable epithelium consisting of pneumocyte cells.

If you remove all the lungs from a person and stretch the alveolar epithelium, its surface is easily enough to cover a tennis court.

How does such an area fit in the chest? Well, the diameter of the alveoli is only 280 microns, and they are compactly crammed into the lungs.

The total area of ​​the alveoli changesE. Fröhlich, A. Mercuri, S. Wu, S. Salar-Behzadi. Measurements of Deposition, Lung Surface Area and Lung Fluid for Simulation of Inhaled Compounds / Front Pharmacol from 30 m² on exhalation to 100 m² on inhalation. For comparison, you are only wearing normal leather from 1.5 to 2.3 m², depending on your height.

3. The heaviest human organ is the skin

By the way, something about the skin, if we are talking about it. Not the heart, not the intestines, not the shinbone, but the skin - the heaviest organ in the human body.

Together with subcutaneous tissue - hypodermis - it Samusev R. P., Lipchenko V. I. Human Anatomy Atlas makes up 16-17% of the total body weight and weighs from 3.5 to 10 kg.

The next largest brain and liver, but their mass is more modestM. D. Kimberley, V. DiMaio. Normal Organ Weights in Men / The American Journal of Forensic Medicine and Pathology. The liver can weigh from 970 grams to 1.8 kilograms, and the brain can weigh from 1,179 grams to 1.6 kilograms.

4. Perfect pitch is more common than you think

When we say "perfect pitch", we imagine a superpower, which is endowed only with Mozart and Paganini. It is often mentioned on the Internet that only one in 10 thousand people is born with such a gift.

This figure did appear in an old article.A. Bachem. Absolute Pitch / The Journal of the Acoustical Society of America Of the Journal of the American Acoustic Society, but it is not supported by any evidence. New research refutes it.

In fact, perfect pitch, that is, the ability to identify notes on the go without listening, is much more common.J. Carden, T. Cline. Absolute pitch: Myths, evidence and relevance to music education and performance / Psychology of Musicthan you think.

On average, one person in 25 is endowed with perfect pitch.

Maybe you also have this ability. True, this is not enough to become a great musician without a long training, but to win a show like “Guess the melody"You will have a good chance.

5. Breast milk and earwax are like sweat

Humans, like many other mammals, sweat. Sweating cools our bodies in hot weather. And people also emitH. Gray. Anatomy of the Human Body; K. S. Saladin. Anatomy and Physiology: The Unity of Form and Function milk (at least females) and earwax.

And from the point of view of evolution, both milk and earwax are also sweat. At least its varieties.

Less developed mammals, such as platypuses, do not have nipples. FemalesPlatypus / Queensland Government they literally sweat milk, it runs down their fur, and the cubs lick it.

This is exactly how the first mammals, our distant ancestors, fed their offspring, about 187 million years ago. At first, the mammary glands were practically no different from sweatR. V. Krstic. Human Microscopic Anatomy: An Atlas for Students of Medicine and Biology;
K. S. Saladin. Anatomy and Physiology: The Unity of Form and Function, but gradually developed into our familiar nipples. The reason is simple: sucking babies is more comfortable than licking their skin, less milk is wasted.

Also, from slightly modified sweat glands in the ears, ceruminousR. V. Krstic. Human Microscopic Anatomy: An Atlas for Students of Medicine and Biology; K. S. Saladin. Anatomy and Physiology: The Unity of Form and Function glands. They create a secret that, when mixed with sebum and dead cells, forms sulfur. It protects the eardrums from debris and bacteria. Ceruminous glands are also found only in mammals.

It is known that people are bigger sweat due to stress (the stronger a person smells, the better the scent scares away predators). And the ceruminous glands in such situations also secreteA. Herane-Vives. Earwax sampling could measure stress hormone / Heliyon more sulfur - just for the company with sweat.

6. Penis and vagina have a common origin

The male scrotum and penis have a crease underneath. And she's there for a reason.

Until a certain stageK. L. Moore, T. V. N. Persaud, M. G. Torchia. The Developing Human: Clinically Oriented Embryology; Z. Wu Jin, Y. Jin, Xi. Wu Li, G. Murakami, J. Francisco Rodríguez ‑ Vázquez, J. Wilting. Perineal raphe with special reference to its extension to the anus: a histological study using human fetuses / Anatomy & Cell Biology the development of the embryo, male and female genital organs do not differ in any way: the set of "blanks" for them is the same. Only after the ninth week does sexual separation begin. Girls develop a vagina, and they also acquire a uterus. Boys have a prostatic uterus and the aforementioned perineal suture as a keepsake from the "blanks".

Penis and clitoris, scrotum and labia, uterus and prostatic uterus, prostate gland and Skene's glands are called homologousS. Arulkumaran, W. Ledger, S. Doumouchtsis, L. Denny / Oxford Textbook of Obstetrics and Gynaecology organs, that is, having a common origin. In general, this is written in biology textbooks, but for many adults it becomes a discovery.

By the way, it is precisely the same development of male and female embryos that explainsWhy do men have nipples? / Nature; Why do men have nipples? / Scientific Americanwhy all people have nipples. They are formed in the same way regardless of gender, it is just that in women they end up being functional, and in men they remain a by-product of development. Here.

7. The intestine has its own nervous system

In your spinal cord J. E. Hall. General Principles of Gastrointestinal Function which allows you to control all movements, there are one hundred million neurons.

But in the nervous system of the intestineJ. B. Furness / The Enteric Nervous System neurons are five times more, that is, five hundred million. Moreover, according to its structureS. A. Green, B. R. Uy, M. E. Bronner. Ancient evolutionary origin of vertebrate enteric neurons from trunk ‑ derived neural crest they are similar to the spinal cord and arise during embryogenesis in the neck, and then they are sent to the intestines.

This complex nervous system is called the enteric nervous system. It regulates the travel of food through the gastrointestinal tract and its absorption.

Usually the intestinal "second brain" is controlled by the body via the vagus nerve. But even if you cut it, the system will continue to function normally.

And the truth is, who needs this vagus nerve, we'll figure it out without it.

And yes, neurons in one only intestines more man J. E. Hall. General Principles of Gastrointestinal Function than in the brain of an ordinary cat. So, figuratively speaking, your guts will be smarter than the average cat. And they purr well if you don't feed them.

8. You can breathe with your anus

Well, at least after a little medical intervention.

Once we wrote about an amazing green-haired short-necked turtlethat lives in the Mary River in Australia. The animal has an interesting respiratory mechanism that comes in handy when it cannot breathe through its nostrils. The turtle exposes the back of the body above the water, draws air into the intestine through the cloaca and assimilates oxygen in this way. Evolution does amazing things at times.

But the turtle is okay. Mammals, as it turned out, can also breathe through the intestines.

A group of scientists managed to teachR. Okabe, T. F. Chen-Yoshikawa, Y. Yoneyama, Y. Yokoyama, S. Tanaka, A. Yoshizawa, W. L. Thompson, G. Kannan, E. Kobayashi, H. Date, T. Takebe. Mammalian enteral ventilation ameliorates respiratory failure / Med mice and pigs metabolize oxygen delivered rectally. They just gave them life-giving O₂ directly into the intestine through anal probes. In addition, in the same way, the subjects' organisms received injected oxygenated perfluorocarbons, which serve as substitutes for blood plasma. So both blood transfusion and oxygen delivery can be through the most seemingly inappropriate place for this.

But the most amazing thing is that such a method can work in humans, assumesVentilating the rectum to support respiration / Japan Agency for Medical Research and Development researcher Ryu Okabe of Tokyo University of Medicine and Dentistry. The fact is that the rectum has a network of thin blood vessels just below the surface of its lining, so that oxygen introduced through the anus is easily absorbed into the bloodstream.

The method, of course, requires further testing, since there is a possibility that part of the oxygen will be shamelessly stolen by intestinal symbiont bacteria. But scientists believe that in the future, rectal oxygen consumption will make life much easier for people with respiratory failure and pneumonia.

So jokes about "booty breathing" in emergency situations turned out to be not so jokes.