Among the various organs of the human body, the skin is one of the more interesting and diverse ones. The skin is much more than just a barrier. It is strong yet supple, fixes or regenerates itself when damaged, and it can change color to adapt to the climate. It is more active than many people realize; it synthesizes a number of compounds including immunoglobulin A, which is important to our immune defense system. The skin plays diverse roles in the body – it helps to regulate the body temperature and it initializes the process of vitamin D production in response to sun exposure. It has absorptive properties which allow it to take in things from the environment, from beneficial medications to harmful toxins. It also excretes toxins via the sweat glands, including phthalates, bioaccumulated toxic elements like cadmium and aluminum, and organochlorinated pesticides. It also secretes oils and acids that keep it supple and protect it from outside invaders.
The skin is part of the integumentary system which includes hair, nails, and certain exocrine glands, such as sweat glands. It is an impossible harmony of specialized cells working in intricate synergy. The skin must have strength and durability yet at the same time it must be flexible and able to repair itself. The skin has three layers – the epidermis, the dermis, and the hypodermis. Each layer has specialized functions. The epidermis is the outermost layer. It is the layer you see when you look at yourself. It is made up primarily of special cells called keratinocytes. As the name implies, these cells produce a substance called keratin, a protein that is durable and water-resistant. Your hair is made of keratin. As these cells mature, they get pushed up towards the surface and they produce lots of keratin. It takes about four weeks for a keratinocyte to go from formation to shedding off the skin’s surface, meaning that on average, we have a new skin layer every month. Increased rubbing makes epidermal cells grow faster, and if the rubbing doesn’t increase skin shedding, a thickened area of skin called a callus will develop. Calluses are a form of hyperkeratosis, a condition where the outer layer of the skin thickens. Another epidermal cell is the melanocyte, which secretes a black pigment called melanin. Skin color is determined by the amount of melanin production and may be regulated by either sun exposure or genetic predisposition.
The middle skin layer, the dermis, contains blood vessels, lymph vessels, nerves, sweat glands, and hair follicles. The dermis plays a vital role in body temperature regulation. When the body heats up in response to exercise or high temperatures, the blood vessels dilate allowing a greater volume of blood to circulate near the skin surface, releasing heat. In addition, sweat glands in the dermis produce more sweat which cools the body when the sweat evaporates on the surface. The hypodermis also contains blood vessels and nerves, but it has a high number of adipocytes (fat cells) which act as insulators and shock absorbers. The hypodermis also anchors the skin to the underlying bones and muscles. Keep your skin in mind every time you go for a check-up as skin changes occur with many different diseases and conditions.
By Peter Galvin, MGBLOG COMMENTS POWERED BY DISQUS