After completing this chapter, you will be able to: List the functions of skin, explain the role of skin in regulating body temperature, describe the layers of skin and the characteristics of each layer, explain the factors that affect skin color, list the accessory organs of skin and describe their structures and functions.
CHAPTER 23 The Integumentary System 23-2 Learning Outcomes (cont.) 23.1 Describe the functions of skin 23.2 Describe the layers of skin and the characteristics of each layer 23.3 Explain the factors that affect skin color 23.4 Summarize types of common skin lesions 23-3 Learning Outcomes (cont.) 23.5 Describe the accessory organs of skin along with their structures and functions 23.6 Explain the process of skin healing, including scar production 23.7 Describe the common diseases and disorders of the skin 23-4 Introduction • Integumentary system – Skin • • – Body’s outer covering Largest organ Accessory organs: • Hair follicles • Nails • Skin glands 23-5 Functions of the Integumentary System • Protection – First line of defense • Bacteria • Viruses – Protects underlying structures • UV radiation • Dehydration 23-6 Functions of the Integumentary System (cont.) • Body temperature regulation – If too hot • Dermal blood vessels dilate • More blood to surface so heat escapes – If too cold • Dermal blood vessels constrict • Prevents heat from escaping 23-7 Functions of the Integumentary System (cont.) • Vitamin D production – Skin must have sunlight – Needed for calcium absorption • Sensation – receptors • Excretion – perspiration 23-8 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 23-9 Skin Structure • Epidermis • Dermis • Hypodermis or subcutaneous layer 23-10 Epidermis • Superficial layer of the skin • Major layers – Stratum corneum • Outermost layer • Mostly dead cells form an impermeable layer – Stratum basale • Deepest layer • Cells constantly dividing and pushing older cells outward To Figure of Skin 23-42 Skin Cancer and Common Skin Disorders (cont.) • Malignant Melanoma – Signs / symptoms • Mole that itches or bleeds • ABCDE rule – Treatment • Surgery • Determination if cancer has spread • Chemotherapy and radiation therapy • Immunotherapy 23-43 Skin Cancer and Common Skin Disorders (cont.) Asymmetry – a mole should not become asymmetrical Border – a mole should not have irregular borders and edges should not blur into normal tissue Color – a mole should not change or become mixture of colors 23-44 Skin Cancer and Common Skin Disorders (cont.) Diameter – a mole should not grow larger than the diameter of a pencil eraser (6 mm.) Evolving – a mole that has been changing in size, color and appearance, or growing in an area of previously normal skin 23-45 Skin Cancer and Common Skin Disorders (cont.) Stages of Melanoma Stage Only found in epidermis Stage I Spread to epidermis and dermis (1 to mm thick) Stage II to mm thick and may be ulcerated Stage III Spread to one or more nearby lymph nodes Stage IV Spread to other body organs or lymph nodes far from original melanoma 23-46 Common Skin and Hair Disorders • Alopecia – Hair loss – Heredity • Dermatitis – Inflammation of skin or a rash – Eczema ~ chronic dermatitis • Cellulitis – Inflammation of connective tissue in skin – Red, tight, painful skin • Folliculitis – Swimmer’s rash – Inflammation of hair follicles 23-47 Common Skin Disorders • Herpes simplex – Type • Cold sores • Spread through saliva – Type – genital • Genital • Sexually transmitted – No cure (cont.) • Herpes zoster – Shingles – Chicken pox virus lies dormant – Symptomatic treatment – Vaccine 23-48 Common Skin Disorders • Impetigo – Oozing skin lesions that eventually crust over (cont.) • Pediculosis – Capitus ~ head lice – Corporis ~ body lice – Pubis ~ pubic lice – Highly contagious • Psoriasis – chronic, inflammatory skin condition 23-49 Common Skin Disorders • Ringworm – Three types • Tinea corporis • Tinea capitis • Tinea pedis – Dermatophytes – Antifungal agents (cont.) • Rosacea – Dilation of small facial blood vessels – Not curable 23-50 Common Skin Disorders • Scabies – Contagious skin condition caused by mites – Redness and itching – Treat entire family (cont.) • Warts – Harmless growths caused by a virus – Vary in appearance – OTC medications 23-51 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 T surrounding tissues _ Lesions of melanoma appear on trunk, head, neck of F men and on arms and legs of women are irregular _ The borders Borders of skin cancers are usually regular T _ Basal cell carcinoma progresses slowly and rarely spreads to other body parts 23-52 Apply Your Knowledge Using Figure for Rule of Nines, determine burn extent for a patient who has burns to his anterior face and both arms Click for 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! 23-53 In Summary 23.1 The functions of skin include: protection, body temperature regulation, vitamin D production, sensation, and excretion 23.2 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 23.3 The amount of melanin affects and determines skin color The amount of oxygen-carrying hemoglobin in the blood also affects skin color 23-54 In Summary (cont.) 23.4 Skin lesions are split among three main types: primary lesions such as macules and vesicles; secondary lesions, which include ulcers and keloids; and vascular lesions, which involve blood vessels and include telangiectasias and ecchymoses 23.5 The accessory organs of skin include: hair follicles, arrector pili muscles, sebaceous glands, sudoriferous glands, and keratin-filled nails 23-55 In Summary (cont.) 23.6 Injured skin becomes inflamed from dilating blood vessels that 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 23.7 Common diseases and disorders of the skin include alopecia, cellulitis, dermatitis, eczema, folliculitis, herpes simplex, herpes zoster, impetigo, pedicuosis, psoriasis, ringworm, rosacea, scabies, and warts 23-56 End of Chapter 23 We may have different religions, different languages, different colored skin, but we all belong to one human race ~ Kofi Annan .. .23- 2 Learning Outcomes (cont.) 23. 1 Describe the functions of skin 23. 2 Describe the layers of skin and the characteristics of each layer 23. 3 Explain the factors that affect skin color 23. 4... 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 23- 9... lesions 23- 3 Learning Outcomes (cont.) 23. 5 Describe the accessory organs of skin along with their structures and functions 23. 6 Explain the process of skin healing, including scar production 23. 7