Anatomical levels of skin

Anatomical levels of skin. Our skin is composed of many layers. The skin plays an important role in us. The average person’s skin is composed of epidermis, dermis and subcutaneous tissue. It is composed of three structures including tissue, so the maintenance of the stratum corneum of the skin is very important. The anatomical layers of the skin are shared below. Anatomical layers of skin 1

Analysis of 7 structures of skin

Analysis of 7 structures of skin: The layers of skin are divided into three major parts: epidermis, dermis, and subcutaneous tissue. Nerves, blood vessels, lymphatic vessels, skin appendages, etc.

1. Tissue structure of skin

1. Skin is the largest human body (organ) that covers the surface of the body and plays an important role in maintaining health and beauty. Healthy skin should be slightly hydrated, soft, pliable, acidic, elastic and shiny. The skin coverage of adult men is about 1.60 square meters, and that of women is about 1.40 square meters. The weight of the skin is about 14%--16% of the body weight.

2. The thickness of skin varies with a person’s age, gender, skin location, and health status. Generally, the skin thickness of various parts of the human body is between 0.5-4mm. The average thickness of men's skin is about 1.15mm. Among them, the skin of the upper eyelids and armpits is very thin, while the skin of the palms and soles of the feet is thicker.

If regular and moderate pressure is applied to any part of the skin, it will thicken the skin and improve the skin's protective effect, but it will have an impact on the digestion and absorption of the skin.

3. Skin color is related to the body’s race, gender, age, living environment, red blood cells in the blood and female hormones in the pineal gland.

4. Each cubic centimeter of skin contains millions of individual cells and an intricate network of blood vessels and nerves.

5. Skin PH value. Sweat and sebaceous glands form a layer of natural epidermis (green ecological protective film) covering the outer skin. The surface of healthy skin is acidic. The pH value of men's skin is close to the middle of 4.5-6, and the pH value of women's skin is close to the middle of 5-6.5.

2. The composition of the skin The skin is divided into three layers:

The epidermis, dermis, and subcutaneous tissue, with nerves and blood vessels in between. , lymphatic vessels, skin appendages, etc.

(1) Integument The integument is the outermost layer of the skin. It covers the whole body and has protective functions. The outer skin has no blood vessels (so it does not bleed easily after being scratched), but there are many tiny peripheral nerves. The outer skin can be divided into 5 layers according to the shape of the somatic cells. From the outside to the inside, they are: thin stratum corneum, transparent layer, granular layer, spinous cell layer, and dermis.

(2) Dermis The dermis is located deep in the epidermis, between the epidermis and subcutaneous tissue. It is mainly composed of connective tissue such as fibroblasts, elastic fibers, reticular fibers and amorphous growth matrix. There are also nerves and peripheral nerves, blood vessels, lymphatic vessels, muscles and their skin appendages.

(3) Subcutaneous tissue Subcutaneous tissue is also called "human adipose tissue". It is located directly under the dermis and has no obvious boundary with the dermis. In human anatomy, it is called superficial fascia. It is called cellular tissue in clinical medicine.

Human adipose tissue is a relatively loose layer of tissue. It is a natural shock-absorbing pad that can buffer outsiders from stress. In addition, it is also a conductor and insulator of heat and can store energy. In addition to fat, adipose tissue also contains rich blood vessels, lymph vessels, nerves, sebaceous glands and hair follicles.

(4) Skin appendages: Skin appendages include hair, sebaceous glands, sebaceous glands, and fingernails. They play very important functions. The damage of any appendages can cause symptoms. Anatomical layers of skin 2

(1) The skin is divided into three layers, from outside to inside, they are epidermis, dermis, and subcutaneous tissue.

(2) The epidermis, which is the outermost layer of the skin, is mainly composed of keratinocytes, dendritic melanocytes, Langerhans cells and a small number of neuroepithelial cells.

According to the different development stages and characteristics of keratinocytes, the epidermis can be divided into five layers. From the outside to the inside, they are the stratum corneum, the transparent layer, the granular layer, the spinous layer, and the basal layer. However, the complete The five layers only exist on the palms, soles of the feet (zhi) and the flexed sides of the fingers and toes, and are also called thick epidermis; the epidermis in other parts of the body is thin and lacks a transparent layer. The thickness of the epidermis is only 0.07~1.2mm.

(3) The dermis is connected to the epidermis on the upper side and the subcutaneous tissue on the lower side. It is divided into papillary layer and reticular layer from top to bottom. Collagen fibers and elastic fibers in the dermis are intertwined into a network, and also contain a small amount of matrix and cellular components. The thickness of genuine leather is 0.4~2.4mm. The dermis is the key layer for maintaining skin elasticity.

(4) The innermost layer of the skin is the subcutaneous tissue. Subcutaneous tissue is mainly composed of fibroblasts and adipocytes.

(5) In addition, the skin also has very important accessory organs, namely hair, hair follicles, sebaceous glands, sweat glands and nails.

(6) Because the skin is an important sensory organ and temperature regulating organ, it has rich nerve distribution, which can help us feel touch, pressure, heat and cold.

(7) There is no blood circulation in the epidermis of the skin, but there is a rich capillary network in the dermis.

(8) There is a network of lymphatic vessels in the skin, parallel to several major vascular plexuses.

(9) There are also muscles in the skin, the most common one is the arrector pili muscle. Striated muscles, the expressive muscles, can also be seen within the facial skin.

(10) In addition, there is a transparent weakly acidic film on the surface of normal skin, which is mainly formed by the emulsification of sebum secreted by sebaceous glands and moisture secreted by sweat glands, which is called sebum. Membrane is the first layer of protective film of the skin. Skin anatomy levels 3

Human skin structure diagram

The skin can be divided from top to bottom: epidermis, dermis, and subcutaneous layer.

Epidermis

The epidermis is the outermost layer of the skin, with an average thickness of 0.2 mm. The cells that make up the epidermis are called squamous epithelial cells (look like fish scales). According to the different cells The development stages and morphological characteristics can be roughly divided into five layers from outside to inside.

First, the stratum corneum: It is composed of several layers of keratinocytes. Although the stratum corneum only has a few layers of dead skin, it forms a wall-like structure for us to maintain the stability of the internal environment of our skin.

Second, the transparent layer: composed of 2 to 3 layers of flat transparent cells with disappeared nuclei, containing keratin.

Third, the granular layer: composed of 2 to 4 layers of flat spindle cells, containing a large number of basophilic hyaline keratin granules.

Fourth, spiny cell layer: It is composed of 4 to 8 layers of polygonal spiny cells, which gradually become flattened from bottom to top.

Fifth, basal layer: It is composed of a layer of cylindrical cells arranged in a grid. These cells continue to divide, gradually move upward, become keratinized, and deform, forming other layers of the epidermis, and finally become keratinized and shed.

The structure of hair on the skin

The hair located above the skin is called the hair shaft, and the hair located below the skin is called the hair root. The cavity where the hair root lives It's called a hair follicle. There are very rich capillaries under the hair follicles. The capillaries need to continuously provide sufficient nutrients to the hair follicles. Only when the nutrients are sufficient can the roots grow well, and only when the roots grow well can the branches and leaves above them grow well.

If the number of capillaries is reduced, the hair follicles will inevitably become drier and shriveled, and eventually the hair on them will fall off.