What is the epidermis: definition, layers and structure
The outer layer of the human body, as, indeed, any other living thing, has a complex structure. The skin consists of several different layers of cells, each of which has its own role. Probably many people know what the epidermis is. This is the topmost, visually visible layer of the skin. It is the state of this layer that the ladies constantly look after, trying to stay young and beautiful for many years. To do this, some beautiful young ladies conduct daily home sessions of cleansing, moisturizing or nourishing treatments. Many representatives of the beautiful half of humanity attend specialized beauty salons, where they are provided with various comprehensive services for the return of beauty, youth and skin health.
Of course, the use of all kinds of nourishing creams and anti-aging lotions is, of course, very good and useful for the outer membranes of our body.However, young beauties often forget that the skin receives the main nourishment from the deeper layers of the epidermis. Internal tissues also contribute to regular skin renewal.
The structure of the skin
It is believed that the skin - these are three layers of cells, tightly adjacent to each other. These include layers of the epidermis, dermis and subcutaneous tissue. The outer epithelial cover, in turn, also consists of five main layers. The layers of the epidermis of the skin are the basal, prickly, granular, shiny and horny zones. Here, the capillaries and blood vessels are completely absent, and the skin receives the main nourishment from a deeper layer, the dermis. The listed layers consist of cells that differ in shape, geometry, and structure; nevertheless, the main component that is present in each of them is keratinocytes.
Interestingly, the thickness of the skin can vary significantly. Depending on the location of the studied area, it can vary from 0.07 mm to 1.5 mm. The most dense layer of skin in any person is located on the palms and feet, and the thinnest and most delicate skin is in the area of the eyes, abdomen, pubis and underarms, as well as on the ears. Now, knowing what the epidermis is, let's take a closer look at its multilayer structure.
The outermost uppermost layer of the epidermis consists of 15–20 rows of tightly attached lifeless cells - corneocytes. There is no metabolism, as there are no organelles in the cells and they are filled with solid insoluble protein - keratin. The outer skin is considered a barrier, since its cells have a protective property to protect the underlying tissue from drying out, bacterial attacks and the harmful effects of the environment. Under the influence of some aggressive factors, the thickness of this layer of the epidermis may increase slightly, increasing the degree of protection.
For some time, the stratum corneum remains holistic due to the interaction between the cells and the extracellular fat (lipid layer). Gradually, this connection is broken, and the skin cells begin to peel off.
Brilliant, or Eleidin, layer
The thinnest, bright, uniform layer, which may not always be pronounced. In addition to corneocytes, the main component here will be eleidin, which is a product for further keratinization of cell masses.The layer consists of no more than four rows of nuclear-free, almost flat cells. It is found mainly in those areas of the skin where additional friction occurs - on the feet of the feet and the palms.
A very thin layer of small, flattened, slightly elongated diamond-shaped cells with transparent nuclei. They have already lost the ability to divide, and in their composition the presence of organoids is reduced and keratogyalin appears - the product for the formation of keratin. The main purpose of this layer is to secrete extracellular fats, which will subsequently fasten the horny cells of the epidermis of the face, hands, neck and other skin areas. In addition, the developed lipids will protect the skin from dehydration and aggressive environmental factors.
This epithelial layer is the thickest, it contains from 5 to 10 rows of polygonal cells. Each cell here consists of a nucleus, cytoplasm, organoids and water. This layer received its name due to the fact that a large number of desmosomes and keratin filaments present here are represented in the form of small processes. The cells themselves have a complex structure.With a careful study, two plates can be found, connected by alternating four electron-transparent and three electron-dense layers. Desmosomes not only provide the structure of the cell, they also guarantee a strong intercellular connection. Knowing the specifics and structure of the skin, that is, understanding what the epidermis is, it can be understood that the deeper the cells are located, the greater the number of desmosomes detected. Due to the structural differences of this layer, keratin synthesis begins here.
The deepest layer is the basal. This is the border between the dermis and the epidermis. It is a basement membrane, on which volumetric cuboid and cylindrical cells are located in one row, where the division process is ongoing. This layer is often called the germ layer, since it is from here that the formed cells begin their path, gradually passing through a certain phase in each epithelial layer. It should be remembered that as they move to the surface of the skin, they are constantly updated and undergo significant structural and biochemical transformations.The process of complete cell renewal, that is, the time cycle from the formation to shedding from the surface of the stratum corneum, takes about 30 days.
The basal layer includes keratinocytes, lymphocytes, basophils, tonofilamen, as well as melanocytes, which produce melanin production and protect the surface of the skin from the aggression of ultraviolet rays.
Epidermis in a smear
Staphylococcus is a conditionally pathogenic microorganism that lives on the body of each person and constitutes local immunity. These microbes can have a lot of subspecies, but not all of them survive in the human body. The most harmful for us are such staphylococci as Staphylococcus epidermidis, aureus, saprophyticus and haemolyticus. These bacteria can multiply, provoking various diseases of the skin, digestive system and mucous membranes of our body.
Epidermal staphylococcus (Staphylococcus epidermidis) is considered the most harmless to humans. He lives in different layers of the skin and does not cause much harm until there are favorable factors for its growth and development. Usually, this infection occurs on the background of medical interventions with the use of poorly processed instruments and in the domestic environment when in contact with the patient.It is well known cases when the defeat occurred as a result of a weakened immune system, a long course or exacerbation of chronic diseases. The main symptoms here are in the form of inflammatory neoplasms on the skin (acne, acne, carbuncles, boils), as well as nausea, vomiting and stomach disorders.
Knowing what the epidermis is, it is easy to guess that infected skin particles freely fall on the mucous membranes of the nose, mouth and eyes. Therefore, the detection of a moderate number of these bacteria is not at all a reason to start immediate treatment. A small presence of staphylococcus in the smear can even be considered the norm. However, if its quantity begins to exceed the allowable value (up to 10⁵ units), treatment is necessary. Otherwise, a large population of pathogenic microbes can cause serious complications.
Consequences of the disease
If time does not begin treatment for the formation of numerous pathogenic staphylococcal microflora, serious diseases can occur. Under conditions when the number of microorganisms begins to exceed the permissible values, the internal organs and whole systems of the body suffer. The main diseases that develop on the background of excessive seeding with a microbe are:
- Urinary tract infections, symptoms of cystitis and kidney damage;
- Erosive processes in the field of gynecology;
- Various forms of conjunctivitis;
- The occurrence of ENT diseases (sinusitis, laryngitis, tonsillitis, inflammation of the tonsils, adenoids and other similar diseases),
- Manifestations of furunculosis neoplasms on the skin and mucous membranes of the body.
Thus, the penetration of epidermal staphylococcus on the mucous membranes still does not give cause for concern. However, with an increase in its amount to 10⁵ or more units in the credits, immediate medical intervention is required.