The skin also known as dermis or cutis is the largest organ accounting for approximately 16% of our body weight. Human skin is on average 1mm thick and consists of 3 primary layers. The Epidermis, Dermis and Hypodermis.
Our skin primary role is to act as an interface between our body and the environment. It protects human from noxious, toxic substances, UV light, heat and microorganisms. The skin is also the most extensive sensory organ of the body for detection of touch, heat and pain and the start of vitamin production.
The Epidermis is the outermost layer of the human body consisting of mostly keratinocytes which produce keratins, a protein that protects epithelial cells from damage or physical stress. Epidermis forms the waterproof, protective wrap over the body’s surface which also serves as a barrier to infection.
Other layers of the Epidermis are stratum corneum (dead flat cells), stratum lucidum (palm of hands and sole), stratum granulosum (cells without nuclear), stratum spinosum (Thickest layer of the epidermis) and finally basal layer. Basal layer is a single cell layer and the deepest of the epidermis and within which are found melanocytes cells responsible for producing melanin or the pigment that gives the skin its tone and light protection.
The Dermis connects the epidermis to the body. It consists of two layers namely the papillary and the elastic. There are also specialised cells and glands within the dermis; sebaceous glands responsible for producing sebum or skin oil, eccrine sweat glands which produce sweat and specialised nerve cell like Meissner’s corpuscles, Pacinian corpuscle, Ruffini corpuscles, Krause’s end bulb and free nerve endings. All of these nerves have different roles including sensing touch, pressure, pain and temperature.
The hypodermis is the largest layer of the skin. Many of the nerves and glands mentioned above are also found in the Hypodermis. This layer has a vast large quantity of fat cells. At the base of this layer, there are series of veins, arteries and lymph channels which collectively regulate blood flow and nerves to receive touch sensation and all of these lies on to of muscles.
When human skin ages, it becomes thinner and more easily damaged. Aging also decreasing the ability of skin to heal itself. Aging skin decreases in volume and elasticity due to various causes like less blood flow and lower glandular activity.
Anti-oxidants are substances that may protect cells from the damage caused by substances that are chemically reactive.
Ultraviolet Light (UVA radiation) is linked with aging effects such as wrinkles. Sunscreens are recommended to be used as a protection agent in areas with high level of UVA.