The Skin is The Sense of Touch
Skin has special receptors for heat, cold, pain, and pressure. The receptors for pain end protrudes into the area of the epidermis. Receptors for pressure in the tip of dermis. Receptors for the sense of touch and heat receptors located near the tip of the epidermis. The skin serves as a protective device inside, such as muscle and bone.
a. Parts of the skin
The skin consists of an outer layer called the epidermis and the inner layer or dermis. In the epidermal layer there is no blood vessels and nerve cells. The epidermis is composed of four layers of cells, namely:
-Stratum germinativum function form a layer on top of it.
-Stratum granulosum that contain keratin which causes the skin to become hard and dry
In addition, the cells of the granular layer generally produces a black pigment (melanin). Melanin content determine the degree of color, black, or brown.
-The lusidum Stratum is a transparent layer.
-The stratum corneum is the outermost layer.
Cross-section images of human skin and its receptors
The main constituent of the dermis is a tissue composed of fibers advocate white and yellow fibers. Yellow fiber is elastic / flexible, so that the skin can expand.
Stratum germinativum held growth to the dermis to form sweat glands and hair follicles
. Hair roots associated with blood vessels that bring food and oxygen,
but it is also associated with nerve fibers. At each base mover muscles attached to hair follicles hair. At the time cold or scared, muscles shrivel hair and hair becomes erect. Next to the dermis there is fat that serves as a cushion to protect the inside of the body from mechanical damage.
b. How is the Works of Skin
Excitatory acceptable skin a touch of heat, cold, pressure, and pain. When the skin receives the stimuli, the stimuli received by the receptor cells. Furthermore, the stimuli will be transmitted to the brain via nerves. By the brain, excitatory be processed. As a result, we feel the presence of a stimulus. The brain also ordered the body to respond to such stimuli.
c. Abnormalities of the skin
The skin is the outermost part (sense of touch) of the body so it is always in touch with their surroundings. Therefore, the skin is injured and attacked by fungi and other germs. Some skin diseases that we often encounter are:
1. Acne. Acne skin is easy to attack the face, neck, back, and chest. This disease arises due to hormonal imbalance and dirty skin. Children who enter adolescence and the people who coined the very oily skin prone to acne.
2. "Panu". "Panu" is caused by a fungus that is stuck to the skin. Panu appear as white spots or dots on skin and itchy. Panu arise because people do not keep the skin clean.
3. Ringworm. Ringworm appears on the skin as scaly white dots. In every circle there is a clear outline of the skin that is not exposed. Ringworm also cause itching. The disease is caused by a fungus.
4. Scabies. Scabies is also called the "seven-year itch". The disease is caused by parasitic insects are very small (Sarvoptes scabies) and can be transmitted to others
. 5. Eczema. Eczema is a skin disease that is acute or chronic. The disease causes the skin to become dry, reddish, itchy, and scaly.
6. Prickly heat. Prickly heat occurs because the sweat glands become clogged with dead skin cells that can not be completely wasted. The trapped sweat causing reddish spots are accompanied by itching. Dirt, dust, and cosmetics can also cause diaper rash.
