What is Skin?

Skin is one of the most amazing organs in the human body. You might be surprised to find out it’s the skin, which you might not think of as an organ. No matter how you think of it, your skin is very important, when we think of an organ the only body part that come s to mind is hear, liver, kidney, etc but in fact if you look at the dictionary definition of “organ”, like this definition from the Merriam Webster Collegiate Dictionary:

Organ – a) differentiated structure (as a heart, kidney, leaf, or stem) consisting of cells and tissues and performing some specific function in an organism b) bodily parts performing a function or cooperating in an activity

The skin is the soft outer covering of vertebrates. Human skin is similar to that of most other mammals, except that it is not protected by a pelt.

The basic facts about our skin are that it’s not only the largest organ in our body but also a study reveals that adults carry some 8 pounds (3.6 kilograms) and 22 square feet (2 square meters) of it. An adult’s skin comprises between 15 and 20 percent of the total body weight. Each square centimeter has 6 million cells, 5,000 sensory points, 100 sweat glands and 15 sebaceous glands.

This fleshy covering does a lot more than make us look presentable. In fact, without it, we’d literally evaporate. If it hadn’t been for our outer covering layer our body would have burnt and wouldn’t be able to handle any of the harmful chemicals in air, sunlight and the extreme changes in the temperature. The body wouldn’t even get the essential nutrients that it requires. The skin acts as a waterproofing sheet on the body. Our skin is extremely sensitive as it contains a variety of nerve endings that react to heat and cold, touch, pressure, vibration, and tissue injury.

The skin is made up of three layers. The outermost is the epidermis. This consists mainly of cells called keratinocytes, made from the tough protein keratin (also the material in hair and nails). Keratinocytes form several layers that constantly grow outwards as the exterior cells die and flake off. It takes roughly five weeks for newly created cells to work their way to the surface. This covering of dead skin is known as the stratum corneum, or horny layer, and its thickness varies considerably, being more than ten times thicker on the soles of the feet than around the eyes. The epidermis harbors defensive Langerhans cells, which alert the body’s immune system to viruses and other infectious agents.

 

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