10 things you don't know about your skin

Do you believe that a thin coat, covered from head to toe, can help protect your body from the wind, waterproof, strong but also flexible and constantly refreshing yourself? Oh! The shirt is your skin!

1. Skin is the widest part of our body. If stretched out, the skin has a surface area of ​​up to 2 m2, equivalent to the area of ​​a normal bed sheet. The skin weighs about 3 kg, about 5% of the body weight. The skin is 0.5 to 5 cm thick depending on the parts of the body: thinner in areas exposed to the environment and pressure; thicker in areas always exposed to things like feet.

2. The skin is composed of 2 layers. The outer horn layer is called the epidermis, consisting of 20-30 rows of dead cells stacked like a roof / tile roof (that's why the skin can stretch easily when we move. dynamic). Every day, thousands of cells peel off the skin in the form of extremely small scales (on the head, sometimes they exist in the form of dandruff on the hair), but this phenomenon does not wear the skin by the cells. That loss is constantly being replaced by the basic inner seed layer.

New cells are born with keratin - a protein that is difficult to absorb, has good tolerance to variations in temperature and humidity. That protein is the main ingredient in nails, nails, clogs, feathers, hair and horns (including rhino-nose). A new cell takes 3 to 4 weeks to reach the outermost layer of the skin (the life cycle of a cell). In this way, we lose about 18 kg during our lifetime.

Human skin structure (Photo: Nlm.nih.gov)

If the epidermis is cut or bruised, the skin will automatically heal without leaving any scars.

3. Under the epidermis are pigment cells (melanocytes). These cells produce melanin (melanin) that helps the body fight ultraviolet rays. When exposed to the sun, the pigment cells that produce melanin make the skin darker: our phenomenon is tanned. Next, these cells move to the outer layer of skin and peel along the keratin cells (horns), which is why the tanning gradually fades away.

Darker skin means more pigment. People with fairer skin are more prone to sunburn, because the amount of melanin on the skin is low - not being able to fight the sun's ultraviolet rays.

4. The second layer is called the skin layer. The upper part contains collagen and elastin, proteins that make skin flexible and flexible. As they get older, these protein materials also degrade. And when they combine with the production of subcutaneous fat (sebum), wrinkles are created.

The skin contains a lot of blood vessels. This layer stretches to fill the vessels when our bodies are warm. This causes the body to lose more heat and lower body temperature. That's why we often blush when it's hot.

When it is cold, the blood vessels of the skin shrink, limiting heat loss, and the skin becomes more pale. When the skin is injured, blood clots, covering the wound to prevent the body from losing more blood and avoiding the invasion of the bacteria.

5. The skin is also home to a lot of nerve endings. These wires can detect small contacts. Simple ends help to sense wounds ingrained into the epidermis. The tip of the finger is where the skin has the best sensitivity to the body.

6. Deep under the skin are sweat glands. Sweat plays a role in reducing the temperature of the skin, eliminating toxins (we sweat even during cold weather days!) And discharging excess salt (that's why sweat tastes good). salty). We produce an average of 250 to 500 ml of sweat per day and up to 2 liters in hot weather days. A person has about 3 million sweat glands, weighing about 100 grams. They often focus on the surface, armpits, soles of the feet and palms. There are about 350 sweat glands on one cm2 of the palm; 200 on 1 cm2 on the back of the hand.

Sweat also helps to catch slippery objects easier. It is believed that this is the main reason why primates keep sweat glands; why so many mammals lose this route: sweat glands help to climb trees.

7. The skin is also the site of many hair follicles (roots, body and skin). Oily glands from the skin layer produce sebum, the lubricant helps lubricate skin and hair. Without mucus, the skin will quickly dry out and crust, losing resistance. Each hair has a muscle fiber placed in the skin.

When cold or frightened, these muscles contract, build hair, form a phenomenon of chicken skin.

8. Under the skin, there is a type of fatty tissue, which acts as a barrier to help the body avoid changes in temperature: it prevents heat loss from occurring, protecting the body from being cold. When needed, the body uses these fatty tissues as an energy source. All ' leftovers ' are placed here.

9. While exposed to sunlight, vitamin D is formed under the skin.

10. Skin helps protect the body from wind, rain, changes in temperature, large sunlight and pathogenic germs.

Bui Thanh