The skin, a multipurpose organ, by Tomás Unger

This month, the Nobel Prize in Physiology and Medicine was awarded to two scientists who study how we feel pressure and heat. Although we intuitively know these two concepts, only in recent years has it been possible to understand the processes that intervene in these sensations.

. The fingertips are what we use most frequently to feel textures, shapes and temperature. This is due to the fact that they have a high concentration of nerves – which makes them more sensitive – and the shape of our hand – which makes the fingers versatile instruments for touching and grasping things.

Various regions of the skin They have different sensitivity and thickness, but all of this has nerve endings that allow us to feel what we touch, whether it is the skin on our back or even the scalp.

—Heat and pressure—

The sense of touch is essential for survival. People who are unable to perceive pain through skin –An extremely rare syndrome– constantly suffer burns, cuts and wounds as they cannot react in time.

What has earned American scientists David Julius and Ardem Patapoutian the Nobel Prize is the discovery of Julius, a biochemist, who studied the way we feel capsaicin, a substance that makes chili peppers spicy. He discovered that the receptor that responds to the presence of that substance is the same one that is activated at high temperatures, indicating pain.

“Different regions of the skin have different sensitivity and thickness.”

Patapoutian, a biologist, also investigated touch on a molecular scale, focusing on the temperature and pressure receptors involved in nociception, the process by which the skin alerts the brain to danger, be it chemical, mechanical, or thermal.

The identified nerve channels also transmit shock, pressure, and swelling, and contribute to the information that kinesthesia, or a sense of space and movement, gives to the brain. Patapoutian and his collaborators have found the genes responsible for nociception, Piezo1 and Piezo2.

—Inner layers—

It is the first line of defense against pathogens, ultraviolet solar radiation and harmful substances. It also protects against bumps and cuts, like a thin soft armor, to the muscles, skeleton, systems (blood, nervous and lymphatic) and internal organs.

The skin is in turn an organ, the largest of all: it covers an average area of ​​almost two square meters. It is a complex structure of three differentiated layers of cells, glands and tissues: epidermis, dermis and hypodermis. Each one has different components and fulfills specific functions.

The epidermis is the outer layer, which is constantly renewed; its basal cells push out old keratin-laden cells, which die and form a protective covering – an armor – at the microscopic level. Basal cells also produce melanocytes, which give color to the skin and protect against ultraviolet radiation.

This layer is covered by hairs and hairs, in some cases so small that they are imperceptible to the naked eye. These help the epidermis to protect the body from pathogens, regulate temperature and reduce the loss of water that the skin transpires.

The middle layer is the dermis, a fibrous tissue that supports and gives firmness and elasticity to the skin. The dermis is the most complex of the layers; In addition to the nerve receptors studied by Julius and Patapoutian, it contains hair roots, blood and lymphatic vessels, sebaceous or fat glands, and sweat glands, which help regulate body temperature. The dermis has two sublayers, one papillary, adjacent to the epidermis, and the other reticular, which borders the hypodermis.

; In any case, it is an essential structure that connects the dermis with the muscles and bones.

The hypodermis mainly contains fibrocytes – which provide structure and contribute to wound healing – macrophages (white cells that eat pathogens, cancer cells and other foreign or harmful materials) and most of the body’s fat, which is used to shelter and protect internal organs.

It should be noted that, although the skin It has three layers, the thickness of these and of the skin itself vary according to the region of the body and the functions it performs. For example, the epidermis tends to be thicker on the soles of the feet due to the need for greater hardness and protection of the surface, constantly exposed to pressure, friction and, in general, greater wear and tear when walking and running.

– Health and care –

The skinBeing our visible layer of the body, it is an important factor in the cultural perception of beauty, and therefore, a reason for vanity and concern. Cosmetology is a separate topic that could go on for many pages; The truth is that the good treatment and care of the skin does not require complicated measures, but it is important since it is an essential organ.

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