Transcript Structure of the Skin Notes

Structure of the Skin Notes
EQ: 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