1. Skin Color Determinants

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 dermis capillaries
Oxygen
Content determines the extent of red coloring
The more oxygen, the more red the skin

3. Skin colors resulting from conditions
Cyanosis
Hemoglobin is poorly oxygenated, and the skin appears blue
Skin becomes cyanotic when a person has difficulty breathing or heart attack
Skin color can indicate emotions or disease
Redness or erythema
Red skin may indicate embarrassment, fever, hypertension, inflammation, or allergy

4. Skin colors cont’d
Pallor or blanching – looking pale – may be anger, fear, anemia, low blood pressure, or impaired blood flow
Jaundice – yellow cast – shows as a yellow skin tone – indicates liver** disorder in which excess bile pigments are absorbed into the blood
Black and blue marks – bruises – blood has escaped from the circulation and clotted in tissue spaces – also called hematomas**

5. SKIN APPENDAGES

6. Appendages of the Skin
Cutaneous glands are all exocrine glands that release their secretion to the skin surface via ducts
2 groups
Sebaceous (oil) glands
Sweat glands

7. Sebaceous glands (oil glands)
Found everywhere except palms of hands and soles of the feet
Produce oil or sebum
Lubricant for skin
Kills bacteria
Most with ducts that empty into hair follicles

8. Sebaceous Glands cont’d
Glands are activated at puberty
Blocked sebum gland’s duct forms a whitehead, a blackhead forms if it oxidizes
Acne is an active infection of the sebaceous glands

9. Sweat glands More than 2.5 million per person
Widely distributed in skin
Produce sweat
Two types
Eccrine
Apocrine

10. Eccrine (Merocrine) glands
Open via duct to pore on skin surface
More numerous and are found all over the body
Help regulate body temperature
If body temperature or external temperature is high, they secrete sweat

11. Apocrine glands Ducts empty into hair follicles
Found mainly in the axillary (arm pit) and genital regions
Begin to function in puberty
Function minimally in thermoregulation
Responsible for odor in humans

12. Sweat and Its Function Composition Function
Mostly water
Some metabolic waste
Fatty acids and proteins (apocrine only)
Function
Helps dissipate excess heat
Excretes waste products
Acidic nature inhibits bacteria growth
Odor is from associated bacteria

13. Hair Produced by hair bulb
Consists of hard keratinized epithelial cells
Melanocytes provide pigment for hair color
Figure 4.7c

14. Hair Anatomy Central medulla Cortex surrounds medulla
Cuticle on outside of cortex
Most heavily keratinized
Figure 4.7b

15. Associated Hair Structures
Hair follicle
Dermal and epidermal sheath surround hair root
Arrector pilli
Smooth muscle
Sebaceous gland
Sweat gland
Figure 4.7a

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

17. Nail Structures Free edge Body Root of nail
Eponychium – proximal nail fold that projects onto the nail body
Figure 4.9