By Eydie Kerfoot LE
The skin is the largest organ of the body (integumentary system) and has many jobs or functions. It is made up of multiple layers and protects the underlying muscles, bones, ligaments and internal organs.
The skin has three layers:
- The epidermis, the outermost layer of skin, provides an acid mantle for protection against microbes and it is a waterproof barrier which prevents epidermal water loss. Although, many consider this the “dead layer”, recent science has proven it is still living in the sense that it still sends messages throughout the body communicating what the cells need.
- The dermis, beneath the epidermis, contains tough connective tissue, nerve endings, blood vessels, hair follicles, oil and sweat glands. The dermis also holds collagen and elastin, proteins that keep skin firm and strong.
- The deeper subcutaneous tissue (hypodermis) is made of fat and connective tissue.
Each layer of your skin performs specific functions that help to cover and protect your body, regulate body temperature and provide you with a sense of touch.
Your skin is your body’s first defense against the elements and foreign invaders. It has a natural pH of 5.5 (acidic) in order to kill off bacteria and pathogens you come in contact with daily. It is important to have and maintain a healthy skin barrier not only for the health of your skin but, your overall health and well being. Skin plays an important role in protecting the body from various kinds of damage, such as loss of water or abrasion from outside.
The integumentary system includes the skin and its appendages (including hair and nails). The integumentary system has a variety of functions; it serving to waterproof, cushion, and protect the deeper tissues, excrete wastes, and regulate temperature, and is the attachment site for sensory receptors to detect pain, sensation, pressure, and temperature. It also provides for vitamin D synthesis and the protection of vitamin B folates. Healthy damaged skin can heal its self. Severely damaged skin will try to heal by forming scar tissue.
Skin performs the following functions:
Protection – The outermost layer of your skin, the epidermis, is the thin, tough part of your body that acts like a protective shell. Because they’re also the first to encounter damage, the cells of the epidermis are constantly renewing themselves, with dead skin cells falling off by the tens of thousands each minute.
One of the most basic functions of the epidermis is waterproofing. Have you ever wondered why your body never absorbs water when you get caught in the rain or take a shower? That’s because the epidermis contains a layer of cells called stratum corneum, which are packed tightly to protect your body against the absorption of harmful substances. This layer also protects your body from losing too much water.
When the epidermis is healthy, it protects the body from bacteria, viruses, infection and other unwanted substances. Protection starts with the natural layer of oil that appears on the outermost surface of the skin, providing the first barrier of protection. The stratum corneum also protects against the invasion of foreign substances. The epidermis also contains Langerhans cells, specialized cells that identify harmful substances and take them to white blood cells to be neutralized. It also contains melanin, the skin pigmentation that helps filter dangerous ultraviolet (UV) rays and prevents the skin from absorbing them, which can cause wrinkles and skin cancer.
The dermis is the layer of skin under the epidermis, and it’s made up mostly of soft tissue such as collagen, elastin, and fibrillin — tissues that make your skin elastic and flexible yet strong and structurally firm. The dermis layer also contains blood vessels, hair follicles, nerve endings, oil glands and sweat glands. It’s the latter of these that makes the dermis so important to heat regulation. The dermis controls body temperature through the production of sweat and the control of evaporation — a process known as insensible perspiration. Basically, the sweat glands of the dermis secrete sweat, which then evaporates on the surface of the skin. Because evaporation requires heat to work, the process of evaporating sweat actually helps to lower the temperature of your skin.
The dermis also regulates temperature by controlling red blood cells. When the body is cold, the red blood cells of the dermis contract, which helps to retain internal body temperature. When the body is hot, the red blood cells expand, allowing heat to be released through the surface of the skin.
The subcutaneous layer is made up of fat cells and fibrous tissue. Like the dermis, the subcutaneous layer helps to regulate body temperature. In this case, however, it provides insulation against the absorption of cold and the loss of heat.
Sensing – The dermis serves an important role in regulating body temperature. But it also performs another critical function: It contains the nerve endings that give you your sense of touch.
The nerve endings in the dermis identify five different kinds of sensations: heat, cold, pressure, pain and contact. This is because there are millions of nerve endings in the dermis, with higher concentrations in certain areas of the body. Places where the skin is thinner often have either a greater concentration of nerve endings or less protection, making them more sensitive.
Injuries to the skin can adversely affect your experience of touch. For example, even a minor burn can be quite painful, because it affects the nerve endings in your skin. Usually, a first- or second-degree burn can continue to hurt even after it has developed scar tissue because the nerve endings are continuing to react to the injury. What’s even more dangerous, however, is when you don’t feel any pain from a burn — that means that you’ve suffered from a third-degree burn, which penetrates the dermis. The reason you don’t feel pain with a third-degree burn is that the nerve endings in the dermis have actually been destroyed.