The Skin
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
Structure of Skin
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
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Dermis
Connective tissue Binds structure of skin
• Inner layer
Elastic fibres Makes the skin flexible
• Made up of
Capillaries Tiny blood vessels
different tissues
and structures 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
Task: Answer the following
• Which layer of the skin do cells • Epidermis
divide and make new ones?
• What happens to skin cells when • Die & flake off
they reach the outer layer?
• Muscles
• What helps the hairs move?
• What gland produces oils? • Sebaceous gland
• What do sensory cells helps us • Touch, pressure,
do? heat, cold, pain
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)
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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