2. Burns Thermal injury or lesion Estimating surface area
Contact with hot object
Contact with fire
Ultraviolet light
Electric current
Corrosive chemical
Estimating surface area
Rule of Palms
Rule of Nines

4. Burns First-degree burn Minor discomfort Reddening of skin
No blistering
Tissue destruction is minimal

5. First Degree Burn

6. Burns Second-degree burn Injury to the upper layers of the dermis
Damage to sweat glands, hair follicles, and sebaceous glands
Tissue death is not complete
Blistering
Severe pain
Generalized swelling
Edema
Scarring is common

7. Second Degree Burn

8. Burns Third-degree burn Destruction of both epidermis and dermis
Tissue death below follicles and glands
May involve muscles, fasciae, or bone
Insensitive to pain immediately after injury
Destruction of nerve endings
Scarring is a serious problem

9. Third Degree Burn

11. Appendages of the Skin Hair Distribution Types
Over entire body except palms of hands and soles of feet and a few other small areas
Types
Lanugo
Fine and soft hair covering the fetus by the 6th month of pregnancy
Usually lost by birth
Vellus
Stronger, finer, less pigmented hairs
Terminal
Replaces 80-90% of the vellus hair on the chest and extremities in males
Females have less vellus hair replaced than males

12. Appendages of the Skin Hair (cont.) Development of hair
Growth begins when cells of the epidermis spread down into the dermis, forming a small tube, the follicle
Follicles consist of two primary layers
Outer dermal root sheath
Epithelial root sheath
Internal layer
External layer
Stratum germinativum forms innermost layer of follicle and germinal matrix
Mitosis of cells of germinal matrix forms hairs

15. Appendages of the Skin Hair (cont.) Papilla Root Shaft Medulla Cortex
Small mound of the dermis protruding into germinal matrix
Contains a cluster of capillaries under germinal matrix
Root
Part of hair embedded in follicle in dermis
Shaft
Visible part of hair
Medulla
Inner core of hair
Cortex
Outer portion of hair
Cuticle
Covering layer

16. Appendages of the Skin Hair (cont.) Appearance of hair Color Growth
Result of different amounts, distribution, types of melanin in cortex of hair
Growth
Hair growth and rest periods alternate
Hair on head averages 5 inches of growth per year
Sebaceous glands
Attach to and secrete sebum (skin oil) into follicle
Male pattern baldness results from combination of genetic tendency and male sex hormones

17. Appendages of the Skin Nails
Consist of epidermal cells converted to hard keratin
Nail body
Visible part of each nail
Root
Part of nail in groove hidden by fold of skin, the cuticle
Lunula
Moon-shaped white area nearest root

18. Appendages of the Skin Nails (cont.) Nail bed Growth
Layer of epithelium under nail body
Contains abundant blood vessels and appears pink under translucent nails
Nails may have pigmented streaks
Separation of nail from nail bed is called onycholysis
Growth
Nails grow by mitosis of cells in stratum germinativum beneath the lunula
Average growth about 0.5 mm per week, or slightly over 1 inch per year

21. Appendages of the Skin Skin glands Two types of sweat glands
Eccrine glands
Most numerous sweat glands; quite small
Distributed over total body surface with exception of a few small areas
Simple, coiled, tubular glands
Function throughout life
Secrete perspiration or sweat; eliminate wastes; and help maintain a constant core temperature
3,000 per in2 on the palms of the hands

22. Appendages of the Skin Two types of sweat glands (cont.):
Apocrine glands
Located deep in subcutaneous layer
Limited distribution—axilla, areola of breast, and around anus
Large (often more than 5 mm in diameter)
Simple, branched, tubular glands
Begin to function at puberty
Secretion shows cyclic changes in female with menstrual cycle

24. Appendages of the Skin Skin glands (cont.) Sebaceous glands
Secrete sebum
Oily substance that keeps hair and skin soft and pliant
Prevents excessive water loss from the skin
Lipid components have antifungal activity
Simple, branched glands
Found in dermis except in palms and soles
Secretion increases in adolescence
May lead to formation of pimples and blackheads

25. Appendages of the Skin Skin glands (cont.) Ceruminous glands
Modified apocrine sweat glands
Simple, coiled, tubular glands
Empty contents into external ear canal alone or with sebaceous glands
Mixed secretions of sebaceous and ceruminous glands called cerumen (wax)
Function of cerumen to protect area from dehydration
Excess secretion can cause blockage of ear canal and loss of hearing

26. Cycle of Life: Skin Children
Skin is smooth, unwrinkled, and characterized by elasticity and flexibility
Few sweat glands
Rapid healing

27. Cycle of Life: Skin Adults
Development and activation of sebaceous and sweat glands
Increased sweat production
Body odor
Increased sebum production
Acne

28. Cycle of Life: Skin Old age
Decreased sebaceous and sweat gland activity
Wrinkling (Figure 6-21)
Decrease of body’s ability to cool itself

29. The Big Picture: Skin and the Whole Body
Skin is a major component of the body’s structural framework
Skin defines the internal environment of the body
Primary functions are support and protection