With an area of one and a half to two square meters, the skin is the largest sensory organ of the human body. It accounts for about one sixth of the body weight. The skin is not only an extremely large organ, but also a very tender one. On average, it only has a thickness of a few millimeters. The wafer-thin body shell is divided into three layers: epidermis, dermis and subcutis.
Protective shield epidermis
The epidermis or epidermis is only about 0.1 millimeters thick - on heavily used body parts, such as the soles of the feet, it can be up to five millimeters as the cornea. The skin surface is covered with a thin layer of water and grease, which keeps it supple and protects against bacteria and fungi. The uppermost layer of the epidermis consists of dead cells called keratin. These horny and glued together cells provide a very resistant protection against mechanical and chemical stimuli. Among them are various layers of horn-forming cells, called keratinocytes, which constantly divide and produce replenishment for the protective shield. These cells rest on the basal membrane, the boundary layer to the underlying dermis. They absorb nutrients and dispose of metabolic waste. The pigment cells or melanocytes, which form the brown pigment melanin for the body's own sun protection, are located in the lowest cell layer of the epidermis. In addition, immune cells of the immune system, the so-called Langerhans cells are found here.
Robust, elastic and sensitive - the dermis
The dermis, also called dermis or corium, consists of two layers: a thin upper zone of loose connective tissue and a thicker lower layer with horizontal bundles of strong connective tissue fibers (collagen fibers). The dermis contains blood vessels as well as nerve fibers with special end organs for the perception of pressure, touch, pain, temperature and itching.
Subcutaneous tissue - fat storage
The subcutis consists mainly of fatty tissue, which is subdivided by connective tissue strands into individual fat lobules. Due to the high proportion of fat cells, which serve as cold protection and energy storage, this skin layer is also referred to as subcutaneous fatty tissue. Here are the larger blood vessels and thicker nerve fibers. The hair roots, sebum and sweat glands are also at home here.
The skin - a real all-rounder
When it comes to functions, the skin also occupies a top position. So it serves as
- Protective shield of the body against the environment
- Protection against heat and cold
- Protective cover against pathogens and radiation
- Storage for nutrients and water
- Excretory organ for degradation products of the metabolism
- Host for drugs and hormones
- sense organ
The skin - mirror of the soul
Phrases such as "This gets under your skin, " "She blushes with shame, " or "I could get out of the skin" show how much skin and soul are connected. The blush of joy, shame or anger arises from the fact that the circulation of the facial skin triggered by certain hormones is increased for a short time in the air. You will be pale with fright, because the blood flow to the heart intensifies reflexively. Whether it is the comforting or unpleasant chill running down your spine or frightening your hair, it is always caused by a sudden contraction of the skin. In addition to these short-term effects, the emotional state can also trigger longer-lasting impairments of the skin. Stress, grief and other mental stress can cause sudden red spots or blemishes. Even over-sensitive reactions to environmental influences, the no-longer-tolerated the usual cream or the usual perfume can be triggered. Conversely, positive moods have a positive effect on the skin. Those who are balanced and happy seem to radiate from within.