1. The Integumentary System
Chapter 26
The Integumentary System

2. The Skin

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Functions of the Skin
Protection
Against invasion by bacteria
Underlying tissue from injury
Against loss of body fluid
Perception
Works with the nervous system to provide a sense of touch
Registers pain, heat, cold, and pressure
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Functions of the Skin
Absorption
Skin can absorb moisture and medication as well as some vital vitamins and minerals through the hair follicles and glands.
Excretion
Skin eliminates water, salt, and waste.
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5. Functions of the Skin Temperature control
When the temperature control center in the brain senses that the body is too warm, blood vessels dilate so that heat escapes through the skin surface.
When it is cold, the vessels constrict to prevent heat loss from the skin surface.

6. Structures of the Skin In 1 square centimeter of skin, there are:
3 million cells
24 sensory apparatuses for heat and cold
200 nerve endings
25 pressure apparatuses
4 yards of nerves
3,000 sensory cells
700 sweat glands
1 yard of blood vessels
15 sebaceous glands

7. How the Body Cools Its Surface
The skin contains sweat glands that produces moisture when the body is too hot.
This moisture evaporates from the skin surface to provide a cooling effect.

8. The Three Layers of Skin Tissue
Epidermis
Top layer
Dermis
Middle layer
Filled with fat, blood vessels, sweat and oil glands, and nerves
Subcutaneous
Inner layer
Contains blood vessels, nerves, and hair follicles
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4 Appendages of the Skin
Sweat glands
Produce moisture to cool the skin surface
Oils glands
Produce oils to prevent hair and skin from becoming dry and brittle
Hair
Nails
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10. The Process That Causes Wrinkles
With age, the elastic fiber in the dermis increases in size, and collagen in the dermis degenerates.
The support for the epidermis is decreased and wrinkles develop.
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11. What Causes a Suntan to Develop
When the skin is exposed to the sun, it may become reddened because of superficial blood vessel dilation.
The melanin pigment increases and moves to the surface to protect the underlying tissue.
A brownish coloration or suntan appears.
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Basal Cell Carcinoma
Slow-growing, locally destructive skin tumor; also called skin cancer
Usually occurs in areas where there are abundant sebaceous follicles
More common in persons over 40, especially those who are blond and fair skinned
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13. Squamous Cell Carcinoma
Invasive tumor that has metastatic potential
Usually occurs in Caucasian men over the age of 60
Working outdoors and smoking increases the risk for developing this cancer.

14. Ordinary Moles versus Melanoma
Shape
Border
Color
Diameter
Development

15. Factors that Contribute to the Development of Melanoma
Intense exposure to ultraviolet (UV) rays from sunlight
Blond or red hair
Fair skin with tendency to sunburn
Blue eyes

16. Blushing The skin has a rich supply of blood vessels.
When we blush, the vessels dilate and cause reddening of the skin.

17. Birthmarks and Moles
Birthmarks can be caused by coloration from a collection of blood vessels or from patches of skin pigment.
Moles are pigmented patches of skin.

18. Albinism
Persons who have little or no skin pigment to give it color are identified as albinos.
The hair is pale yellow or white.
The eyes appear red and are very sensitive to light.

19. Alopecia Loss of hair that usually occurs in the scalp
Physiologic alopecia
Temporary hair loss
Alopecia areata
Limited to small patches of hair loss
Male pattern baldness
Most common form of hair loss
Affects men over age 30

20. Cellulitis
Acute diffuse or spreading inflammation of the skin and subcutaneous tissue
Causes localized swelling, pain, heat, and redness
Usually the result of a streptococcus or Staphylococcus infection

21. Eczema
Acute or chronic skin disorder that results in dry, red, itchy, and scaly skin
Eczema can be irritated by diet, cosmetics, clothing, medications, soaps, and environmental elements, as well as emotional stress.

22. Dermatitis and Folliculitis
Inflammation of the skin
Can refer to any form of skin condition such as seborrhea, eczema, contact dermatitis, exfoliative dermatitis, or stasis
Folliculitis
Infection of the hair follicle with the formation of a pustule
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23. Furuncles and Carbuncles
Hard, painful nodules that develop over time and then rupture and release pus and dead cells through a drainage point
May develop from folliculitis
Carbuncles
Began as a nodule, then enlarge and have multiple drainage points

24. Herpes
Viral infection that causes groups of small, painful, clear vesicles
Type I: Lesions appear in the mouth and nasal area.
Type II: Lesions appear in the genitals.

25. Herpes Zoster Also called shingles
Acute infectious process from the same virus that causes chickenpox
Results in fever, malaise, and usually unilateral eruption of vesicles on the back, chest, or neck

26. Hirsutism and Impetigo
Excessive development of body hair that could be hereditary or the result of an endocrine system disorder
Impetigo
Contagious skin infection with macules and vesicles that erupt and form a characteristic yellow crust
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27. Keloids and Lyme Disease
Scars that develop excess dense tissue as they heal
Lyme disease
Tick-borne disease that is generally the result of a spirochete-infested deer tick

28. Pediculosis The infestation of parasitic lice Pediculosis capitis
Head lice
Pediculosis corpus
Body lice
Pediculosis pubis
Lice attached to pubic hair; commonly called crabs

29. Poison Ivy and Psoriasis
Dermatitis that results from contact with the poison ivy plant
Psoriasis
Chronic inflammatory skin condition that causes red papules covered with silvery scales

30. Rosacea and Ringworm Rosacea Ringworm
Chronic skin eruption that makes the face, especially the nose and cheeks, look flushed
Ringworm
Fungal infection that causes flat lesions that may be dry and scaly or moist and crusty

31. Scabies and Urticaria Scabies Urticaria
Skin infection caused by a skin mite; results in intense itching
Urticaria
Also called hives; a self-limiting reaction to allergens that results in distinct wheals surrounded by reddened areas

32. Verrucae
Also called warts; a benign viral infection of the skin that results in rough, elevated, rounded areas on the skin surfaces