The skin is a highly sophisticated and complex organ. It is composed of intricate internal networks that have specialized functions that work in harmony to provide the immune system at layer of defense from a pathogen attack.
The skin is approximated to be about 15% of an individual’s body weight. Its primary function is to protect your body from external environmental pollutants, physical trauma, and biological assailants. It also contributes to preventing dehydration from fluid loss and regulating internal body temperature.
Skin has a distinctive nature that sets it apart from other organs: it is continuous, containing an internal mucous membrane lining. Clinically, the skin is differentiated into three layers. Each layer is made of different specialized cells.
Three Layers of the Human Skin
Skin is broadly classified into three layers:
The outermost layer of the skin is known as the epidermis. This layer is primarily composed of two types of cells, dendritic and keratinocytes. The difference between the two cell types is in the nature of the cytoplasm.
Cytoplasm is the fluid which is present within every cell containing the cell organelles. In keratinocytes, the cytoplasm is distinctive and all the cells are interconnected through bridges that form a mesh.
Apart from these two cells, the epidermis also contains melanocytes (melanin-containing cells), Langerhans cells (cells that play an important function in antigen presentation) and Merkel cells (responsible for perceiving touch).
The epidermis is further subdivided into four layers based on the morphology and position of the keratinocytes. These are the basal cell layer, the squamous cell layer, the granular cell layer, and the horny cell or cornified layer.
The epidermis acts as the primary barrier to protect the internal organs from sunlight, chemical compounds, and microbial pathogens and provides mechanical resistance.
The middle layer of the skin is known as the dermis. This layer is the major contributor for skin elasticity, flexibility and tensile strength. The dermis and epidermis layer interact to maintain optimal function in both layer of the skin.
It is the layer of integrated filamentous, fibrous and connective tissue to perceive nerve induced stimulus. Also, this is the layer that contains cells like fibroblasts, lymphocytes and other blood cells. The primary component of the dermis region is collagen which is an important structural protein responsible for skin integrity. Collagen protein presents 70% of the skin dry weight.
The principle function of the dermis is to support the epidermis and maintain flexibility, integrity, and elasticity.
The innermost layer of the skin is the subcutaneous tissue which imparts buoyancy and stores energy. Subcutaneous tissue is predominantly made up of fat cells or lipocytes which produce a hormone called liptin. Liptin is an important regulator of body weight.
The efficiency of the skin as a barrier for external factors both biotic and abiotic is imparted through the syndicated functioning of all three layers: epidermis, dermis, and subcutaneous tissue. The epidermis, in its dynamic state, offers the first line of defense to the structure bolstered by the collagen contained in the dermis region.
Learn More About the Different Layers of Skin
Your skin is a vital organ that requires the utmost care. To learn more about the different layers of skin and their importance, contact our office to schedule a consultation with Dr. Howard Horlick.