1. Membranes & Integumentary System (p. 81- 107)
Chapter 3
Membranes & Integumentary System (p )

2. Skin Our skin is an organ
It makes up about 15% of your total body weight
Considered the “Integumentary System” because it…
Contains glands and sensory receptors
Grows hair and nails

3. Membranes Surround and help protect the body’s surfaces 2 Categories
1. Epithelial membranes
2. Connective Tissue membranes

4. Epithelial Membranes
Provide a lining for internal and external surfaces of the body
Epithelial membranes are composed of…
Sheet of epithelial cells
Underlying layer of connective tissue

5. Epithelial Membranes There are 3 types of epithelial membranes
1. Mucous Membranes
2. Serous Membranes
3. Cutaneous Membranes

6. Mucous Membranes
Mucous: slippery solution that protects mucous membranes and aids in transporting substances
Line body cavities that open to the outside world
Respiratory tract (nose, lungs)
Digestive tract (mouth, stomach)
Urinary tract (bladder)
Reproductive tract

7. Serous Membranes
Serous fluid: a thin, clear fluid that serves as a lubricant between the parietal and visceral membranes to minimize friction and “wear and tear” on organs
Line body cavities that are closed to the outside world
Pleura (around the lungs)
Pericardium (around the heart)
Peritoneum (around the abdominal cavity)

8. Cutaneous Membrane What we know as “skin”
Keratinizing stratified squamous epithelium
Underlying dense fibrous connective tissue
Dry membrane when sweat is not present
Contain sweat glands

9. Connective Tissue Membranes
The only membrane only made up of connective tissue
Include no epithelial cells
Only one type: Synovial membranes
Line capsules that surround synovial joints (shoulders and knees)
Serve as cushions for tendons and ligaments surrounding joints
Synovial fluid: clear fluid which provides cushioning and reduces friction and wear on moving structures

10. Functions of the Integumentary System
1. Protection
First line of defense
Outermost layer of skin contains keratin
Tough protein also in hair and nails

11. Functions of Integumentary System
2. Water Barrier
Keratin and natural skin oils serve as a water barrier
Lessens evaporation of water
Prevents water entering body while swimming or bathing

12. Functions of Integumentary System
3. Temperature Regulation
Sweat glands and capillaries lie close to surface of the skin
Body is hot  capillaries dilate  allows heat to leave
Sweat glands activate, sweat evaporates, skin cools
Body is cold  capillaries constrict  blood flow moves toward core of body to minimize heat loss

13. Functions of Integumentary System
4. Vitamin D Production
Melanocytes: specialized cells in the skin that produce melanin
Melanin: pigment that protects the body against harmful UV rays
UVB rays convert modified cholesterol molecules into vitamin D
Vitamin D: essential for bone health

14. Functions of Integumentary System
5. Waste Elimination
Sweating eliminates chemical waste products from the body
Urea, uric acid, salts
**Sweat is acidic and helps protect the body against bacterial infections!**

15. Functions of Integumentary System
6. Sensory Perception
Cutaneous sensory receptors are part of the nervous system
Transmit nerve signals from the skin to the central nervous system
Touch, pressure, vibration, pain, temperature