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- Stem cells divide by mitosis to form new skin cells
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- Keratinocytes
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- Melanocytes
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- To produce melanin
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- Gives colour to hair
- Gives colour to skin
- Protects the skin from UV radiation (sun)
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- Newly formed keratinocytes fill with keratin
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- Many layers of dead flattened skin cells
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- Vitamin D
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- The action of sunlight acting on molecules in the epidermis
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- Provide oxygen and nutrients to the skin
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- Produces sebum
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- Lubricates the skin to prevent cracking to act as a physical barrier
- Contains chemicals that prevent the growth of bacteria
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- Pain receptor
- Pressure receptor
- Touch receptor
- Temperature receptor
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- Produces sweat
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- Carry sweat to the surface of the skin
- Hair Follicle
- Erector Muscle
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- Excess energy
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- Fat
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- Regulating body temperature to 37 degrees celsius
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- Hypothalamus
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- Widening of arterioles in the blood vessels in dermis
- Allows more blood to flow to the surface of the skin
- Heat is lost from the surface of the skin
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- Sweat gland produces sweat
- Sweat travels to surface of the skin through the sweat duct
- Exits the skin through the sweat pore
- This has a cooling effect
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- Narrowing of arterioles in blood vessels in dermis
- Prevent blood getting near the surface of the skin
- Which prevents heat loss
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- Forming of goose bumps
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- Erector muscle attached to the hair contracts
- This pulls the hair upright
- As the hair is pulled upright a layer of skin around that hair traps a layer of warm air near the surface of the skin
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- Acts as a physical barrier to prevent the entry of pathogens
- Produces melanin which protects against UV radiation
- Acts as a sense organ - detects pain, pressure, touch, temperature
- Thermoregulation
- Stores Energy