1. Chapter 6
Integumentary System

2. Organ
Two or more types of tissues grouped together that perform a specialized task.
Integumentary System
Skin plus accessory structures
Skin is the largest organ in our body

3. Functions of skin include
Forms protective coating
Retards water loss
Vitamin D synthesis
Temperature control
Houses sensory receptors

4. 3 Layers of Skin Epidermis Dermis Hypodermis Subcutaneous
Not part of skin

5. Epidermis Outermost layer of skin Stratified squamous epithelium
Outermost layers are keratinized
No direct blood supply – Receives nutrients by diffusion

6. Stratum Corneum Stratum Basale Outermost layer of epidermis
Tightly packed dead cells
Cells are keratinized
Keratin = water insoluble protein
Stratum Basale
Deepest layer of epidermis
Cells are nourished by dermal blood vessels
Site of cell growth and division
Stratum Basal contains Melanocytes

7. Figure 6.3 Epidermis of thick skin

8. Melanocytes
Secrete melanin – pigment
Number of melanocytes is similar in all people
Darker skin from darker and larger melanin granules
Albinism – mutation resulting in no melanin production

9. Figure 6.4a A melanocyte with melanin granules
Figure 6.5 The red eyes and pale skin reflect the lack of melanin in albinism.

10. Dermis Deeper layer of skin Dense irregular connective tissue
Contains dermal papillae
Blood vessels and nerves
Hair follicles
Sweat glands and Sebaceous glands

11. Figure 6.2 Section of skin

12. Sweat Glands
Secrete sweat onto skin surface
Eccrine glands – respond to elevated temperatures
Apocrine glands - anxiety, sexual arousal, and pain
Sebacous glands
Associated with hair follicles
Secretes Sebum – oil
Keeps hair and skin soft and waterproof

13. Figure 6.10 Illustration of sweat glands and sebaceous glands.

14. Hypodermis
Subcutaenous layer – not part of skin
Adipose Tissue, Areolar Tissue, Blood vessels
Binds skin to underlying organs
Adipose insulates the body

15. End of Chapter 6