Structure of the Skin (pp.202-209)

1. General structure
   a.  Covers area of 1.5 to 2.0 square meters
   b.  Accounts for about 15% of body weight
   c.  Usually 1 to 2 mm thick
   d.  Variations: thick and thin skin
   
2. Layers (table 7.1)
   a.  Epidermis
   b.  Dermis
   
3. Hypodermis (subcutaneous tissue)
   
4. Color
   a.  Sources of normal color
   
   • Hemoglobin
   • Melanin
   • Carotene
   b.  Abnormal coloration (table 7.2)
   
5. Markings
   a.  Birthmarks (hemangiomas)
   b.  Moles and freckles
   c.  Friction ridges
   d.  Flexion creases
   

Functions of the Skin (pp.209-211)

1. Barrier functions
   a.  Barrier to pathogens
   
   • Difficulty of physical penetration
   • Antibacterial effect of sebum
   • Acid mantle
   • Inflammation
   b.  Barrier to water
   c.  Barrier to UV radiation
   
2. Vitamin D synthesis
   
3. Cutaneous absorption
   a.  Gas exchange
   b.  Permeability to organic compounds
   c.  Absorption of vitamins, drugs, and poisons
   
4. Sensory roles
   
5. Thermoregulation
   a.  Heat-losing mechanisms
   
   • Vasodilation
   • Perspiration
   b.  Heat-retaining mechanism
   
   • Vasoconstriction
6. Social interaction
   

Hair and Nails (pp.211-216)

1. Hard and soft keratin
   
2. Hair (pili)
   a.  Lanugo, vellus, and terminal hair
   b.  Bulb, root, and shaft
   c.  Medulla, cortex, and cuticle
   d.  Pigments: melanin, trichosiderin
   
3. Hair follicle
   a.  Epithelial root sheath
   b.  Connective tissue root sheath
   c.  Hair receptors
   d.  Arrector pili muscle
   
4. Growth of hair
   a.  Growth and dormant phases
   b.  Alopecia (baldness)
   c.  Pattern baldness
   d.  Hypertrichosis (hirsutism)
   
5. Functions of hair
   a.  Vestigial (most body hair)
   b.  Thermoregulation (scalp hair)
   c.  Protection from sun (scalp hair)
   d.  Recognition of species, sex, etc.
   e.  Association with scent glands (pubic and axillary hair, beard)
   f.  Guard hairs (vibrissae)
   g.  Facial expression (eyebrows)
   
6. Nails
   a.  Structure (table 7.3)
   b.  Diagnostic value
   

Cutaneous Glands (pp.216-218)

1. Sudoriferous (sweat) glands
   a.  Merocrine glands and cooling
   
   • Location and structure
   • Formation of perspiration
   • Insensible perspiration
   • Diaphoresis
   b.  Apocrine glands and scent
   
   • Location and structure
   • Development and function
2. Sebaceous (oil) glands and sebum
   
3. Ceruminous glands and cerumen (earwax)
   
4. Breasts and mammary glands
   

Integumentary Aging and Diseases (pp.218-220)

1. Puberty
   a.  Estrogen and female skin
   b.  Testosterone and male skin
   c.  Effects of testosterone on both sexes
   
2. Senescence
   
3. Skin cancer
   a.  Basal cell carcinoma
   b.  Squamous cell carcinoma
   c.  Malignant melanoma
   
4. Burns
   a.  First-, second-, and third-degree
   b.  Partial- versus full-thickness
   c.  Treatment concerns
   
   • Fluid replacement
   • Infection and asepsis

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