1. The Integumentary System “The Skin” - Anatomy
Notes

2. Sheet-like structures
Membranes
Sheet-like structures
Cover and protect body surfaces
Secrete fluid for lubrication

3. Epithelial Membranes Cutaneous – skin
Serous – lines body cavity & covers surface of organs
Pleura – thoracic cavity
Peritoneum – abdominal cavity
Mucous – line surfaces (openings)
Secrete slimy mucus keeps membranes moist and soft

4. The Skin Did you know? – Draw a 1 inch square on your paper…
1 square inch of skin contains…
500 sweat glands
1000 nerve endings
yards of vessels
100 oil glands
150 pressure sensors
75 heat sensors
10 cold sensors
millions of cells
The whole organ makes up 16% of a person’s body weight

5. Layers of the Skin Epidermis (thin, outer layer) – layers of tissue
Superficial layers (keratinized cells – dry, dead) flake off
Deep layers = rapidly dividing cells (move toward surface)
Cytoplasm replaced by keratin – tough, waterproof protein
Deepest layers produce pigments
Melanin (melanocytes) – genetics/sun exposure
Areas with little melanin used to indicate blood flow (nails/lips)
flushed (normal)
blue (decrease blood flow) – cyanosis

6. Epidermis

7. Layers of the skin
Dermis (deep, thick layer) – cells scattered with fibers
Upper portion forms ridges/grooves – fingerprints
Lower portion contains collagen (strength), elastic fibers, & nerve endings – amount decreases with age

8. Dermis

9. Appendages
Hair – protection/warmth
Erector Pili muscles – goose bumps

10. Appendages Receptors (touch, pain, pressure, temp.)
Sensation becomes part of our awareness when transmitted to brain where info can be…
Amplified
Reduced
Eliminated

11. Appendages
Nails
Protection (hard, plate-like, keratinized cells)

12. Appendages Sweat (sudoriferous) Glands Eccrine gland – watery
Perspiration (eliminate waste, temp. control)
Apocrine gland – thick, milky
Armpit/groin (smell (BO) – bacteria)

13. Appendages
Sebaceous Glands – secrete oil for hair/skin
Sebum – lubrication (prevents drying/cracking)

14. The Skin