15 body secrets you don’t know

The human body is a complex and secret “machine” with many secrets. Although human beings are constantly exploring, they have only discovered a few secrets, and many have not yet been discovered, and these “small parts” are for us to know ourselves. The body played a huge role.

01 Your heartbeat is only 3 billion times in a lifetime
For a normal person, the number of heartbeats in a lifetime is about 3 billion. Therefore, protecting the heart is very important for everyone. Now that cardiovascular and heart diseases are beginning to be younger, everyone should be prevented.

02 Sneeze spreads at a speed of 100 mph
If you encounter someone sneezing in the subway, you should wear a mask even if you are not with you. Because the spread of bacteria in human sneezes is 100 miles per hour. If you are in a car, a sneeze will spread bacteria throughout the car, so remember to wear a mask in a crowded area.

03 Human bones contain 1/3 of the water
In addition to muscles, bones, blood, etc., the human body is mainly composed of water. The proportion of body fluids in the body of adult women is about 55%, and that of men is 60%. But human body fluids are not only stored in the skin, muscles, blood vessels, and organs, but also in the bones. In fact, the water in the bones accounts for 1/3 of the body’s total water.

04 There are as many bacteria as cells in humans
A normal person has about 38 trillion cells, and you may not know that the total number of bacteria on the body is about the same as the number of human cells. If all the bacteria are aggregated together, it is about 225 grams.

05 Why do people sweat?
According to data from the International Hyperhidrosis Association, there are 2 to 4 million sweat glands in the human body, most of which are located on the soles of the feet, palms, forehead and cheeks. Therefore, when a person is nervous or hot, a lot of sweat will come out of the forehead and palm of the hand.

06 How many hairs are there in a person?
Many people have a silly question when they are young: How many hairs are there? Now I finally know. The American Academy of Dermatology points out: People are born with 5 million hair follicles, of which more than 100,000 are located on the scalp. According to a rough estimate, a person has more than 100,000 hairs. And the hair renewal speed of men is faster than that of women, except of course for baldness.

07 The human body is mainly composed of four elements
The human body is mainly composed of four elements: oxygen, carbon, hydrogen and nitrogen. These four elements account for 96.2% of the human body. Of course, there are about 60 other elements such as calcium and phosphorus.

08 How many times does a person breathe in a day?
Exhalation and inhalation are basic physiological activities of human beings, but do you know how many times you breathe every day? People breathe between 17,280 and 23,040 times a day. This reminds us that people’s breathing frequency is different. Improving lung health can make one’s breathing healthier.

09 The surface area of ​​the lungs is too big for you to imagine
Human lungs are basically the same size, but special populations have larger lungs and stronger functions, such as athletes. What you don’t know is that the surface area of ​​our lungs is so large that we can’t imagine that the surface area of ​​all the lung lobes can cover a badminton court or half a tennis court.

Why should 10 people moisturize?
We drink water every day, this is to maintain people’s physiological functioning. Drinking water is one of the most direct methods of moisturizing. Do you know why moisturizing is needed? Because people are expelling water all the time, the amount of water drainage during exercise is 4 times that of normal breathing. When a person is sweating, he can exhale 60-70 ml of water per hour. Therefore, moisturizing not only affects a person’s skin, but also affects physiological functions.

11 Tooth decay is because you don’t have much saliva
A normal person produces 640 ml of saliva per day on average, and a bottle of Coca-Cola is about 350 ml. Therefore, the average saliva of a normal person is about two bottles of Coke a day. In fact, it is good to secrete a lot of saliva. Because saliva can wash away the stench in the mouth and freshen the breath. In addition, saliva is related to dental health. People with insufficient saliva levels are more likely to have tooth decay and oral infections.

12 Everyone is smart
In principle, everyone is smart. But why is there a difference in reality? It is because of the difference in the number of neural connections. There are at least 1 million neural connections in the human brain. If all of these connections are activated, humans will become “gods”. Whether you are learning a language or an instrument, you will quickly learn it.

13 Why do you cut your fingernails more frequently than your toenails?
We often cut our fingernails, but it takes a long time to cut our toenails. Why? It turns out that the growth rate of toenails is slower than that of snails. Toenails can only grow by 1 mm per month, while fingernails grow by 0.1 mm per day, which is 3 mm per month.

14 people have the longest taste memory
The sweet and bitter taste is felt through the human tongue. There are 2000 to 8000 taste buds on the human tongue, and each taste bud has 50 to 100 taste receptor cells. When we eat, we use these taste buds to convey the taste to the brain. This kind of taste memory has the longest time, so even after decades of separation, we will still remember the taste of our childhood.

15 A woman only has 500 mature eggs in her lifetime
When a woman is born, there are 1 million to 2 million eggs in the ovaries, but these eggs will not always exist intact. As they age, they will decrease year by year until menopause. During the entire reproductive period, there are only 500 mature eggs. Therefore, if women want children, it is best not to miss the best fertility period.

Light affects various physiological functions of mammals, including emotions. Many studies have shown that moderate exposure to solar energy during the day improves mood, and the use of “phototherapy” to supplement light can alleviate the symptoms of depressed patients; while at night from light pollution or excessive lighting from electronic devices, it is considered to be at risk of causing depressive symptoms.

Scientists use neural tracing tools to find a special neural circuit. This neural circuit starts in the retina. There are a type of ganglion cells distributed in the retina. They express a protein related to the regulation of the biological clock. These cells are sensitive to light. After they are activated by light, they send signals to the back of a nucleus called the lateral habenular nucleus in the brain, where a part of the nerve cells then project to the nucleus accumbens. These two brain regions are closely related to depression symptoms. Among them, the lateral habenular nucleus is often called the “anti-reward center” of the brain, which mediates many negative emotions. Its overactivity can induce depressive behavior; the nucleus accumbens has a great relationship with pleasure and participates in the formation of depression.

Can noise kill people?
We are always surrounded by noises of different loudness: the noise in the market, the loudness is 70 decibels; the noise of the printing workshop, the loudness is 90 decibels; the starting noise of the old aircraft is over 115 decibels. If it exceeds 115 decibels, the function of the cerebral cortex will be severely degraded; if it reaches 165 decibels, animals will die; if it exceeds 175 decibels, humans will also die. There are even “noise punishments” in wars.

Why do tomatoes become more sour after they are cooked?
The appetizer of tomato soup lies in its sourness, but if you eat tomatoes raw, you will find that it is not so sour. The tomato juice in the tomato soup has been diluted, how can it become more sour?

The acidic components in tomato are mainly citric acid and malic acid, both of which are weak acids, which means that they will be “retained” in the water and will not release all hydrogen ions at once, and hydrogen ions are The fundamental source of sourness.

Within a certain temperature range, the combination and release of hydrogen ions are in dynamic equilibrium. How can we release more?

Increasing temperature is one way. More hydrogen ions are released in the hot tomato soup. In addition, the tomato is cut and boiled, and the material structure that buffers and restrains the sour taste is also destroyed, and the acid is liberated.

On the other hand, the sweetness of the tomato itself is also reduced during the heating process. The sweetness of tomatoes mainly comes from glucose and fructose. The latter is more sensitive to temperature. Fructose is divided into different isomers, and the pyran-type fructose is sweeter. When the temperature rises, the pyran-type fructose will be converted to the furan-type, so the sweetness of the tomato decreases.

How to distinguish water turtles from tortoises?
The easiest way is to look at their toes. Water turtles have full or semi-webbed toes, while tortoises have thicker feet with no webs between their toes. Second, most tortoises have a high domed carapace that protects them from terrestrial carnivores. The shells of water turtles tend to be flatter and suitable for swimming in the water. Water turtles tend to be carnivorous, while tortoises are generally vegetarian.

Why doesn’t the palm of the palm get tanned?

People’s bare skin will be tanned in many places, only the palms and soles of the feet still maintain their “natural colors”. It is understandable that the soles of the feet are not exposed to the sun, but the palms of the hands seem to be not exposed to much sun, right?

Sunlight treats everyone equally, but the distribution of melanocytes in the skin is not. Tanning your skin in the sun is not the same as grilling a barbecue. The skin is tanned because the long-wave ultraviolet rays in the sun activate the melanocytes in the skin, allowing them to produce more melanin. There are fewer melanocytes in the palms of the hands and soles of the feet, so it is naturally difficult to get tanned.

Studies have also found that certain cells in this part of the skin can inhibit the growth of melanocytes and the synthesis of melanin. In addition, the palms of the hands and the soles of the feet often have to directly contact various objects, and the stratum corneum is relatively thick, which can also block part of the ultraviolet rays.

Why does the giraffe bow its head suddenly but not dizzy?
The neck of a giraffe can be as high as 7 meters from the head to the ground. Its lips and tongue can also be stretched, which can make up for the lack of its head and neck. Giraffes rarely drink water, and they can even keep dripping for a few weeks. The water needed by their bodies is often supplied by chewing coniferous food, rubber grass, mimosa, etc.

Giraffes have an extraordinarily strong heart and an extraordinarily thick heart muscle so that they can pump blood to the head. Its blood pressure is several times higher than human blood pressure, and it is also the highest among all animals.

Early observers wondered when they saw the giraffe lowering its head and drinking water. Why wouldn’t the blood pressure rush to the brain cause the giraffe’s fatal cerebral hemorrhage? It turns out that when the long neck of a giraffe suddenly rises or hangs down, in order to withstand the fluctuation of blood rushing into or out of the brain, it has a jugular vein control valve and a special cerebral vascular network. Giraffe’s amazing carotid artery network keeps blood pressure in the brain normal.

Is psychological counseling a simple accompany chat?
An experiment used functional near-infrared spectroscopy to study the brain synchronization between the counselor and the visitor in a psychological counseling situation and compare it with a chat situation. 34 visitors were randomly assigned to a counseling group or chat group for 40 minutes of psychological counseling or chatting. It was found that compared with the chat group, the client and the counselor in the psychological consultation group had stronger brain synchronization in the right temporoparietal complex. It just so happens that the right temporoparietal complex is a brain area related to social connection, cognitive empathy, and theory of mind. This further proves that the psychological counseling group has established a stronger emotional connection than the chat group. It can be seen that psychological counseling is by no means a simple chat.