structure of the skin notes eq: describe the three layers of the skin. eq: identify and locate...
TRANSCRIPT
Structure of the Skin NotesEQ: Describe the three layers of
the skin.
EQ: Identify and locate accessory structures of the skin.
Skin Facts• Largest organ in the body.
• Most of the dust in your home is really dead skin.
• Skin accounts for about 15% of your body weight.
• You grow a completely new layer of skin every 28 days.
• Over 1000 species of bacteria are naturally found on human skin.
Layers of the Skin
• Cutaneous membrane• Epidermis + dermis
Layers of the Skin
• Epidermis• mostly dead cells• Thick skin – 5 layers; hands and feet• Thin skin – 4 layers; everywhere else• Melanocyte – produce skin pigment (melanin)
Squamous epithelium
Layers of the Skin
• Dermis• Living cells• Nerves, blood vessels, glands, collagen
and elastin
Dermal Tissue
Layers of the Skin
• Hypodermis (subcutaneous layer)• Mostly adipose (fat) tissue• Hair follicles
Hypodermal Cells
Accessory Structures of the Skin
• A – hair shaft
• B – sebaceous gland– Produce sebum– Lubricate hairs– Antibacterial
• C – hair follicle
Acne Formation
Accessory Structures of the Skin
• D – arrector pili muscle– Make hair stand up
• E – sweat gland– Homeostasis - as
sweat evaporates, it cools the body
– Body odor
Accessory Structures of the Skin
• F – blood vessel– Bring nutrients to
skin cells– Homeostasis –
warms the skin
• G – nerve receptor– Touch– Pain– pressure
Functions of the Skin Notes
EQ: What are the functions of the skin in the human body?
Recurring Theme
• Homeostasis– Means “steady state”– The body has mechanisms to keep its internal
conditions the same when the environment changes
Function of Epidermis
• Protection– Bacteria– Dirt– Minor wounds
• Melanocytes– Protection from UV
Function of Dermis
• Makes skin elastic and tough– Collagen– Elastin– Fibrillin
• Homeostasis – “goose bumps” caused by arrector pili muscles create insulation
Function of Hypodermis
• Insulation
• Padding
• Energy storage
Functions of Accessory Structures
• Hair – Homeostasis - warmth– Touch sensitivity– Protection from injury
• Melanocyte– Produces melanin– Protects from UV rays