Introduction
The skin (cutis) has two important functions for our body. On the one hand, it has a defensive and protective function, on the other hand it is responsible for the absorption of stimuli. It has the function to ward off harmful influences and to enable physiologically necessary exchange functions (heat exchange) and sensory impressions. The protective functions are very diverse.
1. protection and defense functions
- Protection against mechanical effects Is given to the skin by its tensile strength, stretchability and elasticity
- Protection against chemical noxae and microbial intruders The special structure of the granular layer and the skin surface film (e.g. fat content, pH 5.7, so-called acid mantle) form a barrier to the above-mentioned. If pathogens or molecules should penetrate into the skin, they trigger immunological defense mechanisms.
- Protection against dehydration The evaporation of water in a person without epidermis would be 20l per day.
- Protection against radiation noxae Radiation protection of the skin works by reflecting and absorbing light.
- Immune reactions Once noxious agents have overcome the protective barrier of the skin, the skin can trigger an immune reaction.
- Temperature regulation Temperature is regulated reactively by blood circulation and perspiration. In hot weather, the blood vessels of the skin are dilated and water leaks to the skin surface.
2. the stimulus recording
Merkel – cells are sensory receptors in the epidermis and are considered to be receptors for touch (mechanoreceptors). Numerous nerves and nerve endings are located in the dermis. Free nerve endings conduct cold and heat receptors.
Father – Paccini – corpuscles are mechanoreceptors for pressure and vibration. They are located deep in the dermis or in the deep fatty tissue of the inner surfaces of the hands and feet. Meissner’s corpuscles are touch receptors and are located in the connective tissue of the papillary layer of the dermis.
They are also mainly located on the inner surfaces of the hands and feet. Depending on the location of these tactile corpuscles, they also have different time behaviour. Some with very fast to slow adaptation (adaptation habituation).
- Pain
- Itching and
- Temperature
