Skin Structure 101

It is impossible to understand skincare without having somewhat of an understanding of the skin and how it fully works. Also, the skin is a complex biological organ that provides the outer protective wrapping for all the body parts. Therefore, the largest organ in the body, it is a waterproof, airtight and flexible barrier between the environment and internal organs, keeping the internal environment of our body stable.

The 3 Layers That Make Up Our Skin

The skin is divided into 3 layers, the epidermis, the dermis and the hypodermis.

Epidermis

The epidermis is the outermost and thinnest layer of the skin is a mosaic of cells glued together, its thickness depends on the location on the body. For instance, the epidermis of the forearm skin is thinner than that of the palm and on the eyelids, it is very thin, therefore allows maximum movement. The Epidermis protects against viruses bacteria and parasite infections, while also playing an integral role in protecting the skin from ultraviolet radiation. There are 3 main groups of cells in the epidermis:

1. Keratinocytes (skin cells). Keratinocytes migrate upwards over a period of about four weeks to the outer surface (stratum corneum) where it is shed.
2. Melanocytes (pigment cells). The melanin pigment protects the cells of the epidermis and the tissues in the dermis from sun damage. Lighter skinned people are more susceptible to developing sun-damaged skin because their melanocytes produce less melanin (skin pigment).
3. Langerhans cells (immune cells). These cells act as the first line of defence in the skin’s immune system.

Between the Epidermis and the Dermis, you have the Dermo-epidermal junction. This complex region is where the dermis and epidermis are attached to each other via specialized cells and molecules containing the basement membrane.

Dermis

The dermis lies beneath the epidermis and is 20 to 30 times thicker than the epidermis. Composed of a dense network of specialised proteins (collagen, elastin and hyaluronic acid) organised into fibres of differing sizes and properties. Within the extracellular matrix are blood and lymphatic vessels, nerves, the bottom part of the hair follicles and sweat glands.

• Collagen: The main structural protein found in skin and other connective tissues. Forming a scaffold-like structure it gives rigidity and support to the skin. Some types of collagen fibrils, gram-for-gram, are stronger than steel.
• Elastin: The Skin's 'Youth' Proteins. Elastin is a protein in connective tissue that is responsible for giving structure to the skin and organs. It allows your skin to resume shape after stretching or contracting.
• Hyaluronic Acid: A sugar molecule with a gel-like consistency that is naturally found in skin and joints. With its capacity to bind over 1000 times its weight in water, HA helps our skin attract and retain moisture, which can combat signs of aging.

Hypodermis (subcutaneous layer)

This is a specialized area under the dermis, which contains a network of collagen fibres and fat cells (adipocytes). Also, the thickness of the subcutaneous layer varies according to the location on the body and from person to person. Furthermore, it protects the body from external trauma and insulates from cold. Acting as the main storage site for fat and therefore energy. Also, there are many blood and lymphatic vessels and nerves passing through the subcutis.