The skin is a layer of tissue found in the body surface . On the surface of the skin are sweat glands that excrete residual substances . Residual substances are excreted through the pores of the skin in the form of sweat . Sweat is composed of water and mineral salts , especially salts (NaCl ) which is the result of protein metabolism .
a. Parts of the skin
Human skin is divided into three parts , namely the epidermis ( the epidermis ) , the cuticle ( the dermis ) , and connective tissue under the skin . Each layer is composed of several layers of which has its own function . Consider the following picture .
Epidermis is the outermost skin is very thin and all. Epidermis consists of two layers , namely the stratum corneum and Malpighi layer .
stratum corneum
Stratum corneum layer of the epidermis is the outermost layer of dead and is so easy to peel , have no nucleus , and keratin -containing substances . This layer will always be new , if the peel is not going to hurt or bleed because there are no blood vessels and nerves .
Malpighi layer
Malpighi layer is the epidermis layer of the skin is under the horn . This layer is composed of living cells are constantly dividing. In this layer there are capillaries that contribute to the delivery of nutrients . Living cells that contain melanin . What is melanin ? Melanin is the pigment that colors the skin cells and protect cells from damage caused by sunlight .
Melanin production will increase if too much sunlight so the color will be darker . The other pigment is keratin . If keratin and melanin pigment join , then the skin becomes yellowish color . When malpighinya not contain pigment layer , then that person is called an albino . Each person has a different pigment that is found a variety of skin colors such as white , brown , olive, and black . On the surface of the epidermis contained pores which is the mouth of the oil glands and hair covered , except the epidermis is in the palms of the hands and feet are not hairy . Epidermis on the palms of the hands and feet consists of four layers , namely :
Excretory system in human skin tissue
stratum corneum ,
stratum granulosum ,
lusidum stratum , and
germinalis stratum .
2 ) Leather hides
Leather hides or dermis is the second layer of the skin . Limits to the epidermis by a basement membrane coated . The dermis is thicker than the epidermis . The dermis has an elastic fibers that allow the skin to stretch when people gain weight , and skin sagged when people become thin . In the dermis layer will you meet :
Capillaries , serves to deliver nutrients to the hair follicles and skin cells .
Sweat glands ( glands sudorifera ) , are scattered throughout the skin and serves to produce sweat .
Oil glands ( glands sebaceae ) , serves to produce oil so the skin and hair is not dry and shriveled .
Hair follicle , roots and hair shaft and hair oil glands . At the time of cold and fear , hair on our bodies was established . This is because the hair roots are near the smooth muscle that serves to uphold the hair .
Set of nerve pain , burning sensation nerves , nervous chills, and a touch of nerves .
3 ) The connective tissue under the skin
Connective tissue under the skin is under the dermis . This network does not have a clear boundary with the dermis , as the benchmark is the start there fat cells . In this there are many layers of skin fat . What is the function of the layer of fat ? Fat layer serves to protect the body against impact , hot body , and as a backup energy source .
b . The function of the skin
You have to know the parts of the skin . Do you know what the function of the skin ? Apart from being a expenditure , the skin also serves as a regulator of body temperature , the formation of vitamin D from provitamin D , a place to store excess fat , as a protector , and a sense of touch .
1 ) Equipment expenses
Skin as a means of spending the rest of the metabolism of a substance containing sweat and salt water as well as the rest of the other ingredients .
2 ) The temperature of the body
At the time the body is hot , the blood vessels will dilate and give off heat to the air , and plenty of water released in the form of sweat . Similarly, the body temperature will drop . How to release heat from the skin can also occur with the heat flux from the object being touched , such as clothing touching .
If the body is cold , the blood vessels will shrink , and sweat glands do not secrete sweat . This happens due to the heat from the body to reduce spending . To compensate for this situation , which plays a role in the tool excretion is renal cold state , so we often feel the urge to urinate during the cold .
3 ) The formation of vitamin D
Inside there is a leather pro-vitamin D which can be converted into vitamin D by ultraviolet rays of the sun in the morning . Vitamin D is essential for bone formation .
4 ) Place of storage
Skin and works as a network of bottom water storage . Adipose tissue under the skin as a fat storage . Fat reserves can be burnt to generate heat and energy to cope with the cold air . For this reason, usually people who have a lot of fat or obese people are more resistant to the cold .
5 ) Protective
The skin protects the body from physical disorders such as stress , and disorders that are chemical . In addition , the skin also protects the body from disorders that are biological , such as bacteria and fungi . The skin also keeps the body in order not to lose a lot of water and protect the body from ultraviolet rays .
6 ) Sense of touch
In the dermis there is a collection of nerve stimulation in the form that can capture temperature , pain , and pressure . These stimuli will be delivered to the brain as an information center so we can know what we touch .
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