Integumentary system
Skin
The skin is the body's largest organ. It forms a protective barrier against germs, injury and water loss, controls temperature, and lets us sense touch, heat and pain.
What it is
The skin is a layered organ covering the whole body, made of an outer epidermis, a deeper dermis and an underlying fatty layer.
Where it is
Covering the entire external surface of the body.
What it does
Protects against infection, injury, chemicals and UV; prevents water loss; regulates body temperature; makes vitamin D; and provides the sense of touch, temperature and pain.
How it works
The tough outer layer is constantly renewed, shedding dead cells and forming a waterproof barrier. The deeper layer holds nerves, blood vessels, sweat and oil glands, and hair roots. Sweating and changes in blood flow help control temperature.
When things go wrong
Common conditions affecting the skin
- Eczema and dermatitis
- Acne
- Psoriasis
- Skin infections
- Skin cancer
Education and reference only. This explains the anatomy in plain terms and is not a diagnosis. Sudden severe symptoms — such as severe chest pain, breathlessness or collapse — are an emergency; call 999.
Looking after it
Keeping your skin healthy
Protecting skin from too much sun (sunscreen, shade, covering up), moisturising, not smoking, and checking moles for changes all keep skin healthy.
Did you know?
An interesting fact
The skin is the body's largest organ, weighing several kilograms, and its outer layer is completely replaced roughly every month.
Answers
Skin: frequently asked questions
Is skin really an organ?
Yes — the skin is the body's largest organ. It protects against infection and injury, controls temperature, and provides the sense of touch.
How can I protect my skin from cancer?
Protect skin from strong sun (sunscreen, shade, clothing), avoid sunbeds, and get any new, changing or unusual mole or patch checked by a doctor.
Sources
Where this is drawn from
- NHS — Anatomy and body systems
- Gray's Anatomy for Students
- TeachMeAnatomy / TeachMePhysiology
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