1. Skin Structure
Figure 4.4

2. Normal Skin Color Determinants
Melanin
Yellow, brown, or black pigments
Carotene
Orange-yellow pigment from some vegetables
Hemoglobin
Red coloring from blood cells in dermal capillaries
Oxygen content determines the extent of red coloring

3. Other things that effect skin color
Blushing
Blanching (pale from anger, anemia, etc)
Jaundice (excessive bile pigments from liver)
Bruises – black eye, etc

4. Skin Appendages Cutaneous glands are all exocrine glands
Sebaceous glands
Sweat glands
Hair
Hair follicles
Nails

5. Appendages of the Skin Sebaceous glands
Produce sebum (oil and fragmented cells)
Lubricant for skin
Prevents brittle hair
Kills bacteria
Most have ducts that empty into hair follicles; others open directly onto skin surface
Glands are activated at puberty

6. Appendages of the Skin
Figure 4.6a

7. Appendages of the Skin Sweat glands (aka “sudoriferous” glands)
Produce sweat
Widely distributed in skin (2.5 million!)
Two types
Eccrine – over 2.5 million on your body!
Open via duct to pore on skin surface
Apocrine
Ducts empty into hair follicles
Your axillary and genital regions

8. Appendages of the Skin
Figure 4.6b

9. Sweat and Its Function Eccrine gland: Composition Mostly water
Salts and vitamin C
Some metabolic waste
Function
Helps dissipate excess heat
Excretes waste products
Acidic nature inhibits bacteria growth

10. Apocrine gland:
Sweat also containe Fatty acids and proteins (Bacteria love to eat it!)

11. Appendages of the Skin Hair Produced by hair follicle
Consists of hard keratinized epithelial cells
Melanocytes provide pigment for hair color

12. Second Definition of MATRIX!!
We know it as the material created by connective tissue cells to fill up extracellular space.
BUT
It is also a term used to describe the “growth zone” of skin appendages.

13. Appendages of the Skin
Figure 4.7c

14. Appendages of the Skin Hair anatomy Central medulla
Cortex surrounds medulla
Cuticle on outside of cortex
Most heavily keratinized
Figure 4.7b

15. Appendages of the Skin Associated hair structures Hair follicle
Dermal and epidermal sheath surround hair root
Arrector pili muscle
Smooth muscle
Pulls hairs upright when cold or frightened
Sebaceous gland
Sweat gland

16. Appendages of the Skin
Figure 4.7a

17. Appendages of the Skin
Figure 4.8

18. Appendages of the Skin Nails Scale-like modifications of the epidermis
Heavily keratinized
Stratum basale extends beneath the nail bed
Responsible for growth
Lack of pigment makes them colorless

19. Appendages of the Skin Nail structures Free edge
Body is the visible attached portion
Root of nail embedded in skin
Cuticle is the proximal nail fold that projects onto the nail body

20. Appendages of the Skin
Figure 4.9