Integumentary System
CHAPTER 6
Integumentary System
• Dermatology – scientific study and medical treatment of the integumentary system.
• Integumentary System – consists of the skin and its accessory organs
– hair, nails, and cutaneous glands
• skin is the most vulnerable organ
• skin is the most vulnerable organ
– exposed to radiation, trauma, infection, and injurious chemicals
• body’s largest and heaviest organ
Skin and Subcutaneous Tissue
• consists of two layers:
– epidermis – stratified squamous epithelium
– dermis – connective tissue layer
– hypodermis
• another connective tissue layer below the dermis
• not part of the skin
• contains fat tissue (for insulation), blood vessels and nerves
• thick skin
– on palms and sole, and corresponding surfaces on fingers and toes
– has sweat glands, but no hair follicles or sebaceous (oil) glands
• thin skin
– covers rest of the body
– possesses hair follicles, sebaceous glands and sweat glands
Functions of the Skin
• resistance to trauma and infection
– keratin (mechanical protection)
– acid mantle (prevents bacterial from entering body)
- macrophages –“reach out and touching each other to detect bacteria”
• other barrier functions
– waterproofing
- resists dehydration
– UV radiation
– harmful chemicals
• vitamin D synthesis
– skin is first step of synthesis
– liver and kidneys complete process
• sensation
– skin is our most extensive sense organ
• thermoregulation
– thermoreceptors
– vasoconstriction (when cold)/ vasodilation (when hot)
• transdermal absorption
– administration of certain drugs steadily through thin skin
Structure of the Skin
Cell Types and Layers of the of the Epidermis
Hair Follicle
Hair Follicle
Epidermis
• keratinized stratified squamous epithelium
– dead cells at the surface packed with tough protein – keratin
– lacks blood vessels
– depends on the diffusion of nutrients from underlying connective tissue -dermis
– contains nerve endings for touch and
Integumentary System
• Dermatology – scientific study and medical treatment of the integumentary system.
• Integumentary System – consists of the skin and its accessory organs
– hair, nails, and cutaneous glands
• skin is the most vulnerable organ
• skin is the most vulnerable organ
– exposed to radiation, trauma, infection, and injurious chemicals
• body’s largest and heaviest organ
Skin and Subcutaneous Tissue
• consists of two layers:
– epidermis – stratified squamous epithelium
– dermis – connective tissue layer
– hypodermis
• another connective tissue layer below the dermis
• not part of the skin
• contains fat tissue (for insulation), blood vessels and nerves
• thick skin
– on palms and sole, and corresponding surfaces on fingers and toes
– has sweat glands, but no hair follicles or sebaceous (oil) glands
• thin skin
– covers rest of the body
– possesses hair follicles, sebaceous glands and sweat glands
Functions of the Skin
• resistance to trauma and infection
– keratin (mechanical protection)
– acid mantle (prevents bacterial from entering body)
- macrophages –“reach out and touching each other to detect bacteria”
• other barrier functions
– waterproofing
- resists dehydration
– UV radiation
– harmful chemicals
• vitamin D synthesis
– skin is first step of synthesis
– liver and kidneys complete process
• sensation
– skin is our most extensive sense organ
• thermoregulation
– thermoreceptors
– vasoconstriction (when cold)/ vasodilation (when hot)
• transdermal absorption
– administration of certain drugs steadily through thin skin
Structure of the Skin
Cell Types and Layers of the of the Epidermis
Hair Follicle
Hair Follicle
Epidermis
• keratinized stratified squamous epithelium
– dead cells at the surface packed with tough protein – keratin
– lacks blood vessels
– depends on the diffusion of nutrients from underlying connective tissue -dermis
– contains nerve endings for touch and