Dermis is the thickiest layer of skin, the second one from top. A true Aladdin's cave, it has a wide sort of cells, which each has a clearly defined role. Dermis is also the feeder tissue of the skin, which brings the epidermis the nutrients it needs to be fit, especially through its contact with both the bloodstream and the nervous system! Discover dermis: a real treasure hunt!
The dermis structure
Dermis contains a lot of very different cells.
First, the fixed cells, including fibroblasts. These are star-shaped cells involved in the synthesis of collagen and elastin.
Then, the mobile cells, for instance cells from blood, an element of the immune system and able to enter the blood stream. They help the body against infection and prevent any harm. Among these cells, one may find: macrophages, mast cells, granulocytes, lymphocytes, and finally plasma cells.
Further, we add the renowned fibers of collagen and elastin: collagen fibers provide the mechanical strength of the skin, while elastin gives skin its elasticity and flexibility.
All these cells live in a kind of gel made of water. This gel comprises hygroscopic macromolecules (glycoproteins and proteoglycans), which help to maintain skin hydration and tonus.
Dermis: a friendly home
Dermis functions
- It feeds skin and in particular
epidermis
through tiny blood vessels and the dermo-epidermal junction.
- It is an important agent of the immune defense thanks to all the blood cells it contains.
- It is a kind of water reservoir and allows for the skin retaining some moisture.
- Fibers are a major factor to keep skin firm and flexible at the same time, while its tonus is unchanged.
The dermo-epidermal junction
This "barrier" between epidermis and dermis is a very important area for exchanges between these two layers. This junction is not flat; in fact so as to increase the surface of exchange, it is wave-like all over skin.
