The skin is a true marvel of nature – structure and functions

The skin is a true marvel of nature. It surrounds our entire body like a protective shell, making it the largest organ. Depending on body size, the total surface area of the skin is one and a half to two square meters. Our skin can weigh up to 14 kilograms. Every single square centimeter of skin houses over 5,000 sensory cells and 150,000 pigment cells.

The skin is a true marvel of nature – The structure of the skin

Human skin has a multitude of diverse tasks. To fulfill all these functions reliably, it possesses a sophisticated structure. Under the microscope, three layers are visible: the epidermis, dermis, and subcutis, which are firmly connected to one another.

The uppermost layer of skin is the epidermis (stratum corneum)

This outer skin is the direct connection to the environment and thus represents the actual protective shell. The epidermis itself is divided into five layers. Its outermost layer, the horny layer, is only about 0.5 millimeters thick, depending on the body region and mechanical requirements. In areas subject to greater stress, such as the soles of the feet or the palms of the hands, the thickness of the horny layer can be up to two millimeters. This allows sunlight to be buffered and harmful bacteria and pathogens to be prevented from entering the skin. New cells are constantly formed in the lowest layer of the epidermis (stratum basale). These work their way up layer by layer and are eventually shed in the form of dead skin cells. This becomes visible as small skin flakes on the surface of the skin. The epidermis thus possesses a unique mechanism. This cycle of skin renewal takes an average of 28 days. With increasing age, this process slows down to up to 40 days.

The dermis, also known as the corium, forms the middle layer of the skin

This dermis (stratum papillare) consists of connective tissue fibers that ensure the skin’s elasticity, allowing it to withstand external forces. Unlike the epidermis, the dermis also contains blood and lymph vessels. Its task is therefore to supply the epidermis with important nutrients. Skin appendages such as sweat and sebaceous glands, hair follicles, and a multitude of nerves for perceiving touch, pressure, and vibration are also embedded in the dermis.

The lowest skin layer, also called the subcutis

This also consists of connective tissue, which is somewhat looser than in the dermis and contains deposits of fatty tissue. Since both skin layers consist largely of connective tissue, they are connected to each other in many ways via common connective tissue strands. The subcutis provides protection against the cold and serves as a storage site for fats. This is an important function should the skin ever be exposed to special challenges.

Our skin protects us inside and out – The functions of the skin

This complex structure enables the skin to perform important tasks as a sensory organ. Complex protective functions or metabolic functions are also part of this. All functions are closely linked and support each other. Through sensory cells and fine hairs, we can perceive haptic and thermal impressions from the environment. However, the skin is not only a receiver but also sends information about our emotional state, e.g., in the form of blushing, turning pale, or hair standing on end.

Elastic properties and protective barrier

Thanks to its elastic properties, our skin can withstand certain mechanical forces or can limit and protect against blows and impacts to a certain degree. Healthy skin also forms an important protective barrier against bacteria, viruses, or fungi. Through this effective defense mechanism, pathogens and other external influences such as pollutants or UV radiation can be repelled, thereby avoiding the triggering of inflammatory processes. At the same time, the skin can produce vitamin D, which is important for bones and muscles, under the influence of sunlight. This natural protective barrier also ensures that the body’s water balance is regulated. Through sweating, pollutants and waste products are excreted via water, while the horny layer simultaneously protects the body from dangerous dehydration.

Large-scale skin loss has serious consequences

If only 20 percent of the skin disappears from the body surface, e.g., due to severe burns or accidental wounds, this can be life-threatening for a person. In this case, the body is defenselessly exposed to infiltration by pathogens. In general, severe skin damage can lead to serious health consequences. Therefore, a general strengthening of the immune system and the skin barrier is crucial. Everyone can influence this themselves, e.g., through an adequate supply of water, a healthy diet and lifestyle, and skincare tailored to the skin type to maintain and protect healthy skin.

Interested in more information? Find more in our Skin Journal and on our website.