The dermis layer is one of the main structures of the skin, and the following problems about the skin are related to the dermis layer:
1. Redness, sensitive skin, eye bags, dark circles
2. Skin edema
3. Wrinkles, contour deformation
4. Acne, various inflammations.
This article is divided into dermis layer structure, dermis layer composition, dermis layer function, four chapters of dermal care, the complete reading takes 5 minutes.1. The structure of the dermis layer
1.1 Papillary Dermis
The papillary dermis are papillary protrusions protruding to the bottom of the epidermis, which connect with the epidermis in a canine-toothed shape, and contain rich capillaries and lymphatic capillaries, as well as free nerve endings and cystic necrosomes..
1.2 Reticular Dermis
The reticular dermis is composed of collagen fibers, elastic fibers, cells, and intercellular plasm is thick and located below the papillary layer, in which larger blood vessels, lymphatic vessels, and nerves travel. There is no obvious boundary between the mastoid layer and the reticular layer, which together constitute the microcirculation of the skin and play a decisive role in the health, beauty and epidemic prevention of the skin.
2. Tissue of the dermis
The dermis is divided into three parts from the tissue: fibrous tissue, matrix and cells, belonging to irregular dense connective tissue, of which the fiber component is the mainstay, and there are a small number of substrates and cells between the fibers.
This article is different from the introduction of the epidermis layer in the previous article, the epidermis layer is explained by structure, and this article (dermis layer) is explained by tissue.
2.1 Fibrous tissue
2.1.1 Collagen fibers
Collagen fibers are fiber compositions composed of collagen and amino acids (glycine, proline and hydroxyproline), and are most abundant in the dermis. Collagen fiber is polymerized by collagen fibrils with a diameter of 70~140nm, collagen fiber toughness, strong tensile resistance, but lack of elasticity, in the dermis, the lower part of the direction is almost parallel to the leather surface, is a coarse fiber bundle, interwoven into a net, in different horizontal planes each extended, the lower part of the dermis collagen bundle is the thickest.
2.1.2 Reticulated fiber
reticular fiber is not an independent fiber component, only a naïve, slender immature collagen fiber, with a diameter of 0.2~1.0μm. It is mainly distributed in the papillary layer under the epidermis and around the skin appendages, blood vessels and nerves.
2.1.3 Elastic fibers elastic fibers
have strong elasticity, the main components are proteins, proteoglycans and microfibrils, and different elastic fibers can be distinguished according to their composition and positioning. Elastic fibers are thinner than collagen fibers, 1~3nm in diameter, wavy, interwoven into a net, and entangled between collagen fiber bundles. The number of elastic fibers in the dermis is small, accounting for 2%~4%.
2.2 Matrix
The matrix is an amorphous substance filled in the fibrous bundle space and between cells, and the main component is proteoglycans. Proteoglycans use the tortuous coiled long chain of hyaluronic acid as the skeleton, and combine many core protein molecules through linker proteins to form branch chains, which in turn are connected to many polysaccharide side chains such as keratin sulfate/chondroitin sulfate to form a molecular sieve three-dimensional configuration with many micropores, as shown below. Substances smaller than these voids such as water, electrolytes, nutrients and metabolites can pass freely and exchange substances; those larger than the voids (such as bacteria, etc.) cannot pass through and are limited to locality, which is conducive to phagic cell phagocytosis.
2.3 Cells
There are mainly fibroblasts, mast cells, macrophages, dermal dendritic cells, Langerhans cells and phageocytes, as well as a small number of lymphocytes and white blood cells, among which fibroblasts are the main resident cells in dermal connective tissue. Fibroblasts have the function of synthesizing and secreting three kinds of fibers and matrix, and play a very important role in the renewal of fibers and interstitium and wound repair.
3. The function of the dermis (skin)
3.1 The protective function
Prevents the loss of water, electrolytes and nutrients in the body, protects the internal organs and tissues from harmful factors such as external mechanical, physical, chemical and microorganisms, and maintains the stability of the internal environment.
3.2 Immune function
Immune cells in the skin mainly include Langerhans cells, lymphocytes, macrophages, mast cells, etc., distributed around the superficial capillaries of the dermis and interact, which play an important role in the activation, migration, proliferation and differentiation of immune cells, induction of immune response, inflammatory damage and wound repair.
3.3 Sensory function
The skin is one of the main sensory organs of the human body and can feel various external stimuli.
3.4 Absorption function
The skin has the ability to absorb external substances, which is called percutaneous absorption. The main absorption route of the skin is to penetrate into the stratum corneum cells, and then through the other layers of the epidermis to the dermis and be absorbed.
3.5 Secretion and excretion function
Small sweat glands secrete sweat, which has the functions of heat dissipation and cooling, skin protection, and excretion of metabolites. The sebaceous glands secrete sebum, which forms a lipid film on the surface of the skin and plays a role in lubricating the skin and hair.
3.6 Metabolic function
A variety of metabolic enzymes contained in the skin, which participate in the metabolism of sugars, proteins, lipids, water and electrolytes in the human body.
3.7 The external presentation function
To show the natural beauty of human skin.
Among them, the four functions of 3.4, 3.5, 3.6 and 3.7 complement each other and are inseparable, which can be uniformly summarized as skin microcirculation function.
Skin microcirculation: Refers to the blood circulation between the skin arterioles and microveins, the process of material exchange between blood and dermal tissue cells, the capillaries of microcirculation have only a layer of endothelial cells, the tube wall is very thin, allowing small molecules to enter and exit freely, and the higher concentration of oxygen and nutrients in the blood will be sent from the capillaries to the surrounding tissue cells, and the carbon dioxide and other wastes produced by the metabolism of tissue cells will be taken away by the blood and excreted from the body's excretory organs. Capillaries are distributed only to the dermis layer, and the dermis layer transports nutrients to the epidermis layer, and the waste products metabolized by the epidermis layer are metabolized through the dermis layer.
Dangers of poor skin microcirculation:
- When the tissue is inflamed, the microcirculatory blood flow slows down, the oxygen and nutrients brought to the tissue cells are reduced, and the cells are dystrophy or even die.
- Stasis of blood flow causes the water in the blood to be squeezed outside the blood vessels (red blood streaks, sensitive skin, eye bags, dark circles formation), causing tissue edema, tissue swelling will bring pain and other symptoms, improving microcirculation can reduce edema and pain, promote inflammation recovery.
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With age, the microvascular supply of the skin decreases, the blood supply and oxygen supply are insufficient, the skin nutrition is reduced, the skin elasticity is reduced, sagging and wrinkles, melasma, age spots appear, and crow's feet and bags appear prematurely around the eyes.
4. The care of dermis
The care of dermis, the core is around the auxiliary skin microcirculation, for normal skin auxiliary microcirculation:
4.1 brighten skin tone, lighten spots
4.2 promote cell regeneration, delay aging
4.3 Supplement collagen fibers, lighten wrinkles, repair contours
4.4 Eliminate redness, sensitive muscles, edematous muscles
As mentioned earlier, skin care products, even very expensive skin care products, can only act on the epidermis layer, and the effect on the dermis is minimal, so I think that the future care of the dermis layer needs to rely on physical level instruments, mainly radio frequency beauty devices, which can be better:
a. promote skin microcirculation
b. stimulate fibroblast activity
c. Dermal self-healing mechanism is activated by minimally invasive
Radio frequency beauty device is the pearl of physical skin care equipment, and it is one of the core high-tech ways of skin care in the future. The RF beauty device will be explained in detail in the following article.