1. Skin Cancer, Burns, & Wounds
Hair shaft
Pore
Dermal papillae
(papillary layer
of dermis)
Epidermis
Meissner's corpuscle
Free nerve ending
Reticular layer of dermis
Sebaceous (oil) gland
Dermis
Arrector pili muscle
Sensory nerve fiber
Eccrine sweat gland
Pacinian corpuscle
Hypodermis
(superficial
fascia)
Artery
Vein
Hair root
Adipose tissue
Hair follicle
Eccrine sweat
gland
Hair follicle receptor
(root hair plexus)
Figure 5.1

2. Skin Cancer
Most skin tumors are benign* and do not metastasize*
A crucial risk factor for nonmelanoma skin cancers is the disabling of the p53 gene
Newly developed skin lotions can fix damaged DNA
*Benign = not likely to result in death
*Malignant = likely to result in death
*Metastasis = Cancer cells break off of tumor, and get carried by bloodstream to another part of the body where they grow into a new tumor

3. The three major types of skin cancer are:
Basal cell carcinoma
Squamous cell carcinoma
Melanoma

4. Basal Cell Carcinoma
Least malignant and most common skin cancer
Stratum basale cells proliferate and invade the dermis and hypodermis
Slow growing and do not often metastasize
Can be cured by surgical excision in 99% of the cases

5. Squamous Cell Carcinoma
Arises from keratinocytes of stratum spinosum
Arise most often on scalp, ears, and lower lip
Grows rapidly and metastasizes if not removed
Prognosis is good if treated by radiation therapy or removed surgically

6. Genetic Component: If a family member has had it, your risk increases
Melanoma
Cancer of melanocytes is the most dangerous type of skin cancer because it is:
Highly metastatic
Resistant to chemotherapy
Genetic Component: If a family member has had it, your risk increases

7. Skin Cancers
Figure 5.7a–c

8. Melanomas ofhave the following characteristics (ABCDE rule)
A: Asymmetry: the two sides of the pigmented area do not match
B: Border is irregular and exhibits indentations
C: MultiColored (pigmented area) is black, brown, tan, and sometimes red or blue
D: Diameter is larger than 6 mm (size of a pencil eraser)
E: Evolving: the mole changes over time, usually growing larger

9. Melanoma
Treated by wide surgical excision accompanied by immunotherapy
Chance of survival is poor if the lesion is over 4 mm thick

10. Primary Risk Factor for Cancer: El Sol!
Primary risk factor is exposure to UV light from sun or tanning beds
Most sun exposure occurs in youth – sunburns that peel linked to increased likelihood of melanoma
1 in 5 people in US get skin cancer, odds increase to 1 in 3 in “sunbelt” states
Exposure to UV light increases at higher elevations, when on the water, and when on snow
Avoidance: clothing, sunscreen, time of day, check-ups

11. Burns, Wounds, and Aging of the Skin

12. First-degree – only the epidermis is damaged
Burns
First-degree – only the epidermis is damaged
Symptoms include localized redness, swelling, and pain

13. Second-degree – epidermis and upper regions of dermis are damaged
Burns
Second-degree – epidermis and upper regions of dermis are damaged
Symptoms mimic first degree burns, but blisters also appear

14. Third-degree – entire thickness of the skin is damaged
Burns
Third-degree – entire thickness of the skin is damaged
Burned area appears gray-white, cherry red, or black; there is no initial edema or pain (since nerve endings are destroyed)

15. Estimates the severity of burns
Rule of Nines
Estimates the severity of burns
Body mapped into regions that are multiples of 9% of the surface
Burns considered critical if:
Over 25% of the body has second-degree burns
Over 10% of the body has third-degree burns
There are third-degree burns on face, hands, or feet

16. Rule of Nines
Figure 5.8a

17. Healing of Wounds and Burns 1
A. Inflammation, in which blood vessels dilate and become more permeable, which causes tissues to become red and swollen, is the body's normal response to injury. The increased blood flow brings extra nutrients (to assist growth of new cells) and white blood cells (to attack bacteria) to the wound. B. Superficial cuts are filled in by reproducing epithelial cells – mitosis occurs in the stratum basale.

18. Healing of Wounds and Burns 2
C. Deeper cuts are closed off by clots, covered by scabs, and eventually filled in by fibroblasts, making connective tissue. Blood vessels extend into the area, injured tissues are replaced, and the scab falls off. D. Large wounds leave scars and healing may be accompanied by the formation of granulations (bumpy regions).

19. Developmental Aspects of the Integument: Fetal
Epidermis develops from ectoderm
Dermis and hypodermis develop from mesoderm
Lanugo – downy coat of delicate hairs covering the fetus
Vernix caseosa – substance produced by sebaceous glands that protects the skin of the fetus in the amnion

20. Developmental Aspects of the Integument: Adolescent to Adult
Skin and hair become oilier and acne may appear
Skin shows the effects of cumulative environmental assaults around age 30
Scaling and dermatitis become more common

21. Developmental Aspects of the Integument: Old Age
Epidermal replacement of cells slows and skin becomes thinner
Skin becomes dry and itchy
Subcutaneous fat layer diminishes, leading to intolerance of cold
Decreased elasticity and loss of subcutaneous tissue leads to wrinkles
Decreased numbers of melanocytes and Langerhans’ cells increase the risk of skin cancer