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CHAPTER 20 The Integumentary System © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-2 Learning Outcomes 20.1 List the functions of skin. 20.2 Explain the role of skin in regulating body temperature. 20.3 Describe the layers of skin and the characteristics of each layer. 20.4 Explain the factors that affect skin color. 20.5 Identify and describe common skin lesions. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-3 Learning Outcomes (cont.) 20.6 List the accessory organs of skin and describe their structures and functions. 20.7 Explain the process of skin healing, including scar production. 20.8 Describe the effects of aging on skin. 20.9 List the different types of burns and describe their appearances and treatments. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-4 Learning Outcomes (cont.) 20.10 Describe the causes, signs and symptoms, and treatments of various types of skin cancer. 20.11 Describe the causes, signs and symptoms, and treatments of common skin disorders. 20.12 Explain the ABCDE rule and its use in evaluating melanoma. 20.13 Using the acronym CAUTION, list the seven warning signs of cancer. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-5 Introduction • Integumentary system consists of skin and its accessory organs • Accessory organs: – Hair follicles – Nails – Skin glands Skin is the body’s outer covering and its largest organ. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-6 Functions of the Integumentary System • Protection – First line of defense against • • Bacteria Viruses – Protects underlying structures from • • Ultraviolet (UV) radiation Dehydration © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-7 Functions of the Integumentary System (cont.) • Body temperature regulation – If too hot • • Dermal blood vessels dilate Vessels carry more blood to surface so heat can escape – If too cold • • Dermal blood vessels constrict Prevents heat from escaping © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-8 Functions of the Integumentary System (cont.) • Vitamin D production –Needed for calcium absorption • Sensation –Sensory receptors • Excretion – Small amounts of waste products are lost through perspiration © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-9 Apply Your Knowledge What are the functions of the integumentary system? ANSWER: The functions of the integumentary system are protection, regulation of body temperature, vitamin D production, sensation, and excretion. Super! © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-11 Epidermis • Most superficial layer • Two parts – Stratum corneum • Outermost layer • Mostly dead cells form an impermeable layer – Stratum basale (stratum germinativum) • Deepest layer • Cells constantly dividing and pushing older cells outward To Figure of Skin © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-12 Epidermis (cont.) • Keratinocyte – most common – Makes and accumulates keratin • Durable protein that makes the epidermis waterproof and resistant to pathogens • Melanocyte – Makes the pigment melanin • Traps UV radiation and prevents damage to underlying layers of the skin © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-13 Dermis • Deeper of the two skin layers • Contains all major tissue types, plus – Sudoriferous (sweat) glands – Sebaceous (oil) glands – Hair follicles and arrector pili muscles – Collagen, elastin, and nerve fibers – Blood vessels • Binds the epidermis to the subcutaneous tissue To Figure of Skin © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-14 Subcutaneous Layer • Hypodermis • Composed of – Adipose (fat) and loose connective tissue – Blood vessels and nerves • Functions – Storage in adipose tissue – Cushions and insulates underlying structures To Figure of Skin © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-15 Apply Your Knowledge Where are melanocytes and keratinocytes, and what is their function? ANSWER: Both are located in the epidermis of the skin. Keratinocytes make and accumulate keratin, which is a durable protein that makes the epidermis waterproof and resistant to pathogens. Melanocytes make the pigment melanin, which traps UV radiation and prevents damage to underlying layers of the skin. Excellent! © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-16 Skin Color • Determined by amount of melanin in the epidermis of skin • The more melanin, the darker the skin color – Range is from yellowish to brownish © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-17 Skin Color (cont.) • Oxygenated blood – Amount of oxygen dissolved in the hemoglobin of the red blood cells • Hemoglobin – a pigment in the RBCs – If blood is well-oxygenated, skin will be pink – If oxygen level in blood is low, skin will be pale or have a bluish color (cyanosis) © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-18 Apply Your Knowledge What affects skin color? ANSWER: The amount of melanin produced by the melanocytes and the oxygenation of the blood. Nice Job! © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-19 Skin Lesions • Any variation in the skin – As simple as a freckle – As serious as a tumor © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-20 Skin Lesions (cont.) Lesion Name Description Bulla A large blister or cluster of blisters Cicatrix A scar, usually inside a wound or tissue Crust Dried blood or pus on the skin Ecchymosis A black-and-blue mark or bruise Erosion A shallow area of skin worn away by friction or pressure Excoriation A scratch; may be covered with dried blood © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-21 Skin Lesions (cont.) Lesion Name Description Fissure A crack in the skin’s surface Keloid An overgrowth of scar tissue Macule A flat skin discoloration, such as a freckle or a flat mole Nodule A large pimple or small node Papule An elevated mass similar to but smaller than a nodule Petechiae Pinpoint skin hemorrhages that result from bleeding disorders © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-22 Skin Lesions (cont.) Lesion Name Description Plaque A small, flat, scaly area of skin Purpura Purple-red bruises usually due to clotting abnormalities Thin plaques of epithelial tissue on skin’s surface Scale Pustule An elevated (infected) lesion containing pus Tumor A swelling of abnormal tissue growth © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-23 Skin Lesions (cont.) Lesion Name Description Ulcer A wound that results from tissue loss Vesicle A blister Wheal Another term for hive © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-24 Apply Your Knowledge Match the following: C Keloid ___ ANSWER: A. A blister A Vesicle B. A crack in the skin’s surface ___ E Crust ___ C. An overgrowth of scar tissue B Fissure D. A small, flat scaly area of skin ___ F Ulcer ___ E. Dried blood or pus on the skin D Plaque ___ F. A wound that results from tissue loss © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-25 Accessory Organs • Hair follicles – Tube-like depressions in the dermis of skin – Generate hairs – Alopecia (baldness) occurs when follicles die – Arrector pili muscles attached to follicles cause goose bumps • Sebaceous glands – Produce sebum to keep hair soft – Prevent bacteria from growing on skin • Nails – Protect the ends of fingers and toes – Hard keratin Diagram © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-26 Accessory Organs (cont.) • Sudoriferous (sweat) glands – Located in the dermis of skin – Types • Eccrine gland – Produce watery type of sweat – Activated by heat • Apocrine gland – Produce thicker type of sweat with more proteins – Concentrated in armpit and groin areas – Activated by nervousness or stress Diagram © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-28 Skin Healing • Injury inflammation – Redness due to dilation of nearby blood vessels – Swelling because vessels leak fluid into spaces between cells – Pain because excess fluid activates pain receptors © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-29 Skin Healing (cont.) • Inflammation promotes healing – Extra blood to area Injury occurs – Extra nutrients for skin repair – Defensive cells Blood clot forms Scab replaces blood clot Collagen fibers replace scab Clotted blood and other dried tissue Bind the edges of wound; major component of scars © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-30 Apply Your Knowledge How does inflammation promote healing of the skin? ANSWER: Inflammation promotes healing by bringing extra blood, nutrients for skin repair, and defensive cells to the area of injury. Correct © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-31 Skin and Aging • Skin loses firmness due to – Loss of elastin and collagen fibers in dermis – Loss and shifting of underlying adipose tissues • Skin color changes – Dermis becomes thinner and more transparent – Paler due to decrease in circulation © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-32 Skin and Aging (cont.) • Melanocytes decrease – Those remaining gather “age” spots – Hair grays and becomes thinner • Decreased tolerance to temperature changes – Sudoriferous glands decrease in number • Decreased perspiration, hard to adjust to high temperatures – Loss in adipose tissue and decreased circulation • Increased sensitivity to cold © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-33 Apply Your Knowledge What happens to the skin in the elderly? ANSWER: As a person ages, the skin loses firmness, skin color changes, melanocytes decrease, and tolerance to temperature changes decreases due to a loss of adipose tissue and sweat glands. Very Good! © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-34 Burns • Second leading cause of accidental death in the U.S. • Rule of nines is used to determine extent (coverage) of burn – Extent of body surface area – 11 body areas Rule of Nines © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-35 Back © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-36 Burn Severity Superficial – first-degree Partial-thickness – second-degree Epidermis only Pain, redness, swelling Epidermis and dermis Pain, redness, swelling, blisters Full-thickness – third-degree All layers of skin and often underlying structures Skin appears charred Always requires medical attention Burns © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-37 1st Degree 2nd Degree 3rd Degree Back © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-38 Burns: Treatment • Do not remove anything sticking to the burn • Do not apply butter, lotions, or ointments • Cool with large amounts of water • Cover with sterile sheet or plastic bag © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-39 Apply Your Knowledge Using Figure 24-5, determine burn extent for a patient who has burnt his anterior face and both arms. Click for Figure 24-5 Rule of Nines ANSWER: Face = 4.5% Both arms, hands, and shoulders = 18% 4.5% + 18% = 22.5% It all adds up to a right answer! © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-40 Skin Cancer • Basal cell carcinoma – progresses slowly and rarely spreads to other body parts • Squamous cell carcinoma – more likely to spread to surrounding tissues • Malignant melanoma – more aggressive and occurs anywhere – Most arise from melanocytes © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-41 Basal Cell Carcinoma Signs and symptoms New growth or sore that will not heal Waxy, smooth, red, pale, flat, or lumpy May or may not bleed Treatment: Curettage and electrodessication Cryosurgery Mohs’ surgery Laser therapy © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-42 20-42 Squamous Cell Carcinoma • Less common than basal cell carcinoma • Found on face, lips, ears, and backs of hands • Signs and symptoms and treatments are the same as for basal cell carcinoma © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-43 Malignant Melanoma • Signs and Symptoms – From melanocytes – Appear on trunk, head, neck of men – Appear on arms and legs of women – Itches or bleeds • Treatment – Surgery and biopsy – Removal of lymph nodes – Chemotherapy and radiation therapy – Immunotherapy © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-44 Stages of Melanoma Stage 0 Only found in epidermis Stage I Spread to epidermis and dermis (1 to 2 mm thick) Stage II 2 to 4 mm thick plus ulceration Stage III Spread to one or more lymph nodes Stage IV Spread to other body organs or lymph nodes far from original melanoma © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-45 ABCDE Rule A Asymmetry – a mole should not become asymmetrical. It should look equal in size from side to side. B C D Border – a mole should not have irregular borders and edges should not blur into normal tissue. E Evolving – a mole that has been changing in size, color and appearance, or growing in an area of previously normal skin Color – a mole should not change or become mixture of colors. It should have even coloring. Diameter – a mole should not grow larger than the diameter of a pencil eraser (6 mm.) © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-46 24-46 Cancer Warning Signs C– A– U– T– I – O– N– Change in bowel or bladder habits A sore that will not heal Unusual bleeding or discharge Thickening or lump Indigestion or difficulty swallowing Obvious change in wart or mole Nagging cough or hoarseness © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-47 Apply Your Knowledge True or False: ANSWER: F Basal cell carcinoma is the most aggressive form of skin ___ cancer and can form anywhere. Melanomas are more aggressive. T Squamous cell carcinoma is more likely to spread to ___ surrounding tissues. T Lesions of melanoma appear on trunk, head, neck of ___ men and on arms and legs of women. F The borders of skin cancers are usually regular. ___ Borders are irregular. T Basal cell carcinoma progresses slowly and rarely ___ spreads to other body parts. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-48 Common Skin Disorders Alopecia • – Results in hair loss Dermatitis Cellulitis • – Inflammation of connective tissue in skin Eczema Inflammation of skin or a rash Chronic dermatitis Folliculitis Inflammation of hair follicles © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-49 Common Skin Disorders (cont.) • Herpes simplex • – Type 1 – cold sores – Type 2 – genital • – Head lice – Body lice – Pubic lice Herpes zoster – Shingles • Pediculosis Impetigo • Psoriasis – Inherited autoimmune disorder – Oozing skin lesions that eventually crust over © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-50 Common Skin Disorders (cont.) • Ringworm – Tinea corporis – Tinea capitis – Tinea pedis • Rosacea – Dilation of small facial blood vessels • Scabies – Contagious skin condition caused by mites • Warts – Harmless growths caused by a virus © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-51 Apply Your Knowledge Match the following: ANSWER: C Alopecia ___ A. Dilation of small facial blood vessels ___ E Folliculitis B. Inherited autoimmune disorder ___ F Impetigo C. Hair loss B Psoriasis ___ D. Growths caused by a virus ___ A Rosacea E. Inflammation of hair follicles ___ D Warts F. Oozing skin lesions Right! © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-52 In Summary 20.1 The functions of skin include protection, body temperature regulation, vitamin D production, sensation, and excretion. 20.2 When the body is warm, the dermal blood vessels dilate, allowing heat to escape and cool the body. When the body is cool, the same vessels constrict, preventing the heat carried by blood from escaping, keeping the body warmer. 20.3 The topmost layer of the skin is the epidermis. The dermis is the complex middle layer. The innermost layer, attaching the skin to muscle, is the subcutaneous layer. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-53 In Summary (cont.) 20.4 The amount of melanin affects and determines skin color. The amount of oxygen-carrying hemoglobin in our blood also affects skin color. 20.5 Skin lesions are split among three main types: primary lesions such as macules and vesicles; secondary lesions include ulcers and keloids; vascular lesions involve blood vessels and include telangiectasias and ecchymoses. 20.6 The accessory organs of skin include hair follicles, arrector pili muscles, sebaceous glands, sudoriferous glands, and keratin-filled nails. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-54 In Summary (cont.) 20.7 Injured skin becomes inflamed from dilating blood vessels which leak and cause swelling. A blood clot is formed, which is replaced by a scab, which is then replaced by collagen fibers that produce scar tissue. 20.8 Skin loses elasticity with aging as well as the youthful glow because of the loss of collagen and elastin fibers. The loss of melanin also causes graying and thinning of the hair. The loss of adipose tissue and decreased number of sudoriferous glands makes it difficult to readily adjust to temperature changes. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-55 In Summary (cont.) 20.9 First-degree burns affect only the epidermis and are known as superficial burns. Second-degree burns or partial thickness burns involve both the epidermis and dermis. Third-degree or full-thickness burns affect all skin layers and underlying structures, including muscle and bone. 20.10 There are three types of skin cancer: basal cell, squamous cell, and malignant melanoma. Signs of skin cancer vary, as do the treatment methods for each type. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-56 In Summary (cont.) 20.11 Common skin disorders: the signs, symptoms, and treatments for these conditions are found in the Pathophysiology section at the end of the chapter. 20.12 ABCDE is the acronym used to remember the signs of possible melanoma when looking at suspicious moles on the body. A = Asymmetry, B = Border, C = Color, D = Diameter, and E = Evolving. 20.13 The seven warning signs of cancer are: C = Change, A = A sore, U = Unusual, T = Thickening, I = Indigestion, O = Obvious change, and N = Nagging cough. © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 20-57 End of Chapter 20 We may have different religions, different languages, different colored skin, but we all belong to one human race. ~ Kofi Annan © 2011 The McGraw-Hill Companies, Inc. All rights reserved.