Skin is the largest organ in the human body. It can be up to two square metres in extent. It covers our entire body and is responsible for protection. Further functions include:
Regulating body temperature
Decreasing water and bodily fluids loss (to prevent dehydration)
Containing our sensory receptors (nerves)
Synthesising biochemicals (for example synthesis of Vitamin D)
Excreting waste and toxins (sweating)
The thickness of our skin varies over the body. It also varies in thickness between men and women. It is proven that men do indeed have thicker skin.
The skin is made up of three layers:
The epidermis is the outermost layer of the skin. It contains no blood vessels. The easiest way to remember this is to think about when you get a paper cut. It usually doesn’t bleed because it only cuts through the epidermis.
This layer is made up of five layers: Stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale. Each layer has a function in the process of keratinization. Simply put, the process of keratinization is where the layers of the skin move up through the epidermis, change shape and form keratin until they reach the top layer and are then sloughed off, or desquamated. This is where exfoliation helps to remove these dead skin cells.
This process takes on average four weeks. This is usually why, when cosmetic products make claims, they will test the product over a minimum of four weeks. It takes about that length of time for changes in the skin to be evident, as the changes will take place from the basal layer.
The basal layer also contains melanocytes which produce melanin which determines the colour of your skin.
The dermis is home to most of the skin’s structure, such as sweat and oil glands, hair follicles, blood and lymph vessels and nerve endings. It is the dermis that responds to the senses of heat and touch.
The main components are elastin and collagen. This is what changes as we age. Younger skin has more collagen and elastin. This starts to break down as we age and is responsible for wrinkles and sagging skin. Collagen gives the strength and elastin the elasticity.
The hypodermis is the deepest layer of skin. It is also known as subcutaneous tissue. This is where fat cells (adipocytes) and fibroblasts are stored. Collagen is formed in this layer. The hypodermis conserves body heat and is the body’s shock absorber.
It also contains larger blood vessels and nerves than are contained in the dermis.
For more read Skin Bio Part 2