1. The Skin

2. About the skin Largest organ of the body
Covers and protects everything inside the body
Controls body temperature
Allows us to have the sense of touch through nerve endings
Skin can become infected with bacteria, viruses and fungi
Mends itself when damaged

3. Structure of Skin

4. Epidermis Top layer (outer covering) Made up of flat, dead cells
These dead cells shed from our body
Inner part of the epidermis is made up of dividing cells
These cells push upwards and replace the dead cells

5. Dermis Inner layer Made up of different tissues and structures
Connective tissue
Binds structure of skin
Elastic fibres
Makes the skin flexible
Capillaries
Tiny blood vessels
Muscle fibres
Move the hairs
Sensory cells
Touch, pressure, heat, cold, pain
Nerve fibres
Activate muscles and glands, send messages to brain
Sweat gland
Goes up to the surface
Hair follicles
Hair grows through to the epidermis
Sebaceous gland
Produce oil to keep skin waterproof
Inner layer
Made up of different tissues and structures

7. Task: Answer the following
Epidermis
Die & flake off
Muscles
Sebaceous gland
Touch, pressure, heat, cold, pain
Which layer of the skin do cells divide and make new ones?
What happens to skin cells when they reach the outer layer?
What helps the hairs move?
What gland produces oils?
What do sensory cells helps us do?

8. Controls temperature Body temperature is normally 37°c
Hypothalamus- part of the brain that controls temperature
Too hot: Start to sweat
Blood vessels open up more (vasodilation)
Too cold: Goosebumps & Shiver
Hairs stand up
Warm air is trapped against the skin
Blood vessels constrict (vasoconstriction)

9. Skin facts Melanin is a pigment in our skin that gives us colour.
The darker you are the more melanin you have.
An albino person has no melanin
Keratin is produced in the epidermis
This helps keep skin waterproof
with the oil