1. The Integumentary System
The Skin and its Appendages

2. The Skin
Two main components
Epidermis
Dermis
(Hypodermis)

3. Epidermis Cells of the Epidermis Keratinocytes Melanocytes
Dendritic Cells (Langerhans cells)

4. Epidermis Layers of the Epidermis Thick Skin Thin Skin Stratum Basale
Stratum Spinosum
Stratum Granulosum
Stratum Lucidum
Stratum Corneum
Thin Skin
Absence of Stratum Lucidum

5. Epidermis Layers of Epidermis Stratum Basale (germinatum)
Single row of stem cells
10-25% melanocytes
very small amount of tactile cells

6. Epidermis Layers of the Epidermis Stratum Spinosum several cells thick
weblike intermediate filament network
melanin granules and dendritic cells present

7. Epidermis Layers of the Epidermis Stratum Granulosum
Keratinization Begins
Keratohyaline granules
Lamellar granules

8. Epidermis Layers of the Epidermis Stratum Lucidum
Only present in thick skin
2-3 rows of clear, flat, dead keratinocytes

9. Epidermis Layers of the Epidermis Stratum Corneum anucleate
20-30 cells thick
¾ of epidermis
high keratin content
thickened, glycoprotein covered plasma membranes
loses 50k cells/min

10. Dermis Composition Connective Tissue proper
Rich nerve and vascular supply
contains hair follicles, glands, and sensory receptors
Layers
Papillary Layer
Reticular Layer

11. Dermis Papillary Layer Thin areolar highly vascularized
low density (great for phagocytes)
Dermal papillae (form friction ridges in thin skin)

12. Dermis Reticular layer 80% of Dermis dense irregular connective tissue
blood vessel network (cutaneous plexus)
cleaveage and flexure lines

13. Appendages of the Skin Hair and Hair Follicles Nails Sweat Glands
Eccrine Glands
Apocrine Glands
Sebaceous (oil) Glands

14. Appendages of the Skin Hair and Hair Follicles Structure of hair
Structure of a hair follicle
Types and growth of hair
Hair thinning and baldness

15. Appendages of the skin Structure of a hair (fig 5.5) Regions
Produced by hair follicles
Conists primarily of dead keratinized cells
cells contain hard keratin
Regions
Shaft
Root
Concentric Layers
Medulla
Cortex
Cuticle

16. Appendages of the skin Structure of a Hair Follicle (fig 5.5)
Epithelium based
Hair bulb
Hair follicle receptor
Hair papillae
Peripheral connective tissue sheath
Epithelial root sheath

17. Appendages of the Skin Types and Growth of Hair Vellus Hair
Terminal Hair

18. Appendages of the Skin Hair Thinning and Baldness Alopecia
True Baldness (Male Pattern)

19. Appendages of the Skin Nails (fig 5.6)
Scale-like modification of epidermis
hard keratin
free edge, nail plate, root
nail bed
nail matrix
nail folds and cuticle

20. Appendages of the Skin Sweat (Sudoriferous) Glands
Eccrine (Merocrine) Sweat Glands
Apocrine Sweat Glands

21. Appendages of the Skin Sebaceous (Oil) Glands
Simple branched alvolar glands
secrete sebum
holocrine type glands
secrete into hair follicles and occasionally pores

22. Skin Functions Protection Chemical Barriers acid mantle
Physical Barriers
Biological Barriers
dendritic cells, macrophages, DNA

23. Skin Functions Body Temperature Regulation Heat Loss Vaodilation
heat loss through sweat evaporation
Heat conservation
Vasoconstriction

24. Skin Functions
Cutaneous Sensation

25. Skin Functions Metabolic Functions Produces vitamin D precursor
disarm cancer causing chemicals
activate some steroid hormones

26. Skin Functions
Blood Resevoir
5% of total blood volume

27. Skin Functions
Excretion
ammonia, uric acid, urea, salt, water.

28. Homeostatic Imbalances of Skin
Skin Cancer
Basal Cell Carcinoma
Squamous Cell Carcinoma
Melanoma
Asymmetry
Border Irregularity
Color
Diameter
Elevation

29. Study Guide
Will Post Wednesday