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 www.abpischools.org.uk/page/modules/skin/skin2.cfm?coSiteNavigation_allTopic=1

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

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?

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) http://www.abpischools.org.uk/page/modules/skin/skin3.cfm?coSiteNavigation_allTopic=1

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