Healthremedy123.com – The skin is the largest organ in your body and acts as your first line of defense against disease and infection. It holds body fluids in, keeping us hydrated, and keeps harmful microbes (MYE-krohs) out.
Skin Forms a Barrier Against Harmful Elements
The outer layer, called the epidermis, makes new skin cells each day and sheds old ones every 30 days. The middle layer, the dermis, contains blood vessels, nerves, hair follicles and sebaceous (oil) glands. Like body armor, skin protects the vital organs of the integumentary system (ay-TEH-mentary) from outside elements such as heat, cold, microorganisms, and harmful chemicals. The skin forms a barrier against these harmful elements and helps the integumentary system regulate the movement of water, salts, and nutrients.
The skin is made up of three major layers – the epidermis, dermis, and subcutis – each with its own functions. The epidermis, also called the horny layer, is the outermost protective layer. Its surface contains closely packed, oily, dead cells that form a hydrolipid film that helps seal in moisture. Underneath the epidermis is the dermis, which has blood vessels and nerves as well as hair follicles and sweat glands. The subcutis contains fatty tissue that nourishes the dermis and epidermis.
The skin is one of a group of organs that are able to sense the thermal environment (see Werner 2010). It is the only non-hairy body surface that covers specialized heat-exchange organs. It possesses the first characteristic that Werner describes for an auxiliary feedforward control signal: it responds to changes in the thermal environment more quickly than does deep body temperature. This reduces the load error in the thermoregulation system and thus contributes to stable body temperature.
The Outer Layer of the Skin is Stratified Squamous Epithelium
For example, when the skin temperature drops, blood vessels in the outer layer of the skin (the epidermis) tighten up to conserve body heat. In addition, the body’s brown adipose tissue releases heat into the air through vasodilation and sweat secretion. The inner layer of the skin, called the dermis, contains nerves and blood vessels. The skin and its appendages (hair, nails, oil and sweat glands) are like body armor that protects the vital organs from the influences of bacteria, chemicals, sunlight and temperature extremes. It also provides a barrier against insensible fluid loss.
The outermost layer of the skin is a stratified squamous epithelium made up of proliferating basal cells that are differentiated into keratinocytes. This layer helps keep harmful microorganisms out of the body and essential water in2. A series of sphincterlike blood vessels control the flow of blood through the skin. The underlying subcutis layer stores fat to serve as an energy reserve and protects against injury. The hairs on the skin lie flat rather than erect, increasing the flow of air next to the surface and thus helping prevent heat from being trapped.
The skin and its nerve endings give the brain information about the temperature of objects you touch. For example, if you put your hand in a hot tub, the nerves tell your brain that your finger is burning and that you need to pull it away from the water. The skin can also help keep you warm. When the air temperature drops, blood vessels in the skin tighten and narrow to decrease heat loss from the body through the surface of the skin, a process known as vasoconstriction, according to the Cleveland Clinic. This is the same mechanism that creates goose bumps, which are an inherited thermoregulatory response from our furry animal ancestors. The skin also keeps you cool by absorbing sweat and turning it into vitamin D through sunlight exposure.
Skin Helps Keep Body Fluids in
The skin helps keep body fluids in, preventing dehydration (deh-HYE-duration). It also keeps harmful microbes out. It keeps the body cool by releasing sweat, which evaporates and helps lower body temperature. It releases vitamin D when it is exposed to sunlight.
The top layer, the epidermis, is made of cells that produce a protective coating called keratin. Cells in the epidermis are gradually pushed to the surface by newer cells. Once the epidermis is filled with keratin, it forms a hard shell or stratum corneum. Beneath the epidermis is the dermis, which contains blood vessels, nerves, hair follicles and oil glands. The dermis also has a network of nerve fibers that send signals to the brain about heat, cold and pain. We are happy to receive guest post submissions from you.