Functions of the Skin
The main functions of the skin include:
- Protection of the human body
- Sensation i.e. transmitting to the brain information about surroundings
- Temperature regulation
- Immunity i.e. the role of the skin within the immune system
- Enables movement and growth without injury
- Excretion from the body of certain types of waste materials
- Endocrine function e.g. re. Vitamin D
It is useful to be able to describe each of the above functions of the skin in further detail with examples and explanations of the mechanisms that apply in each case.
Function of the Skin |
Example(s) |
How does the skin perform this function ?
What is/are the mechanism(s) ? |
1. Protection |
Of the body from:
- ultraviolet (UV) radiation e.g. sun damage
- dehydration
- microorganisms
e.g. bacterial invasion
- mechanical trauma / physical injuries
|
- The physical/mechanical barrier formed by the surface (stratum corneum layer) of the skin.
- Mechanical strength of the tissues that form the skin.
- Keratin - a type of protein that is found in the skin.
- Melanin - a dark-coloured light-sensitive pigment that is found in the skin and that protects against excessive amounts of ultraviolet (UV) radition, usually coming from the sun.
|
2. Sensation |
Pressure/touch, heat/cold, pain |
- Somatic sensory receptors
|
3. Temperature Regulation |
Retention or release of heat - depending on outside of body temperature |
- Release of sweat from sweat glands followed by evapouration of sweat from the surface of the skin (body)
- Regulation of blood flow to regions of skin, especially the extremities of the body (i.e. limbs / appendicular skeleton)
|
4. Immunity |
Destruction of microorganisms & interaction of skin with the body's immune system |
- Langerhans cells (of the epidermis)
- Phagocytic cells
- Epidermal dendritic cells
|
5. Permits movement & growth |
Growth of body / bodily tissues and adaptation of contours of body/skin during movement |
- Elastic properties of skin (epidermis and dermis)
- Recoil properties of the skin (epidermis and dermis)
- Elastic properties of subcutaneous tissue
- Recoil properties of subcutaneous tissue
|
|
See the structure of skin for info about layers of skin. |
|
6. Excretion |
Excretion of water, urea, ammonia and uric acid |
- Waste products released from the body via the surface of the skin, regulated by the volume and composition of sweat
|
7. Endocrine |
Synthesis of Vitamin D |
- Vitamin D (strictly D3, as there are different types of vitamin D) is made when an organic chemical in the skin called 7-dehydrocholesterol reacts with UVB ultraviolet light - usually due to natural daylight but could be from articifical sources - that falls onto the skin. Vitamin D3 is produced in the two innermost layers of the skin - called the stratum basale and stratum spinosum.
However, it is important to also be aware than excessive amounts of ultraviolet light, especially over a certain range of wavelengths, falling onto the skin may lead to sunburn and is also associated with an increased risk of skin cancer - which may occur later.
|
 |
|
|
|
Note that the information above summarises the main functions of the skin only.
Different textbooks and websites list different numbers of 'main functions' of the skin. Coursework and exam questions often ask for a specific number of examples of functions of the skin.
Generally, lists of functions of the skin such as in the table above are given in no particular order but there may be an order of importance of functions of the skin (or 'integumentary system') in or for specific situations. For example when playing badminton inside a leisure centre regulation of body temperature and excretion of waste products from the body may be more important that synthesis of vitamin D because the latter applies primarily in situations of natural daylight.
