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Unformatted text preview: Chapter 5 The Integumentary System Objectives 1. Name the tissue types composing the epidermis, dermis and hypodermis. List the major layers of each and describe the functions of each layer. 2. Describe the factors that normally contribute to skin color. Briefly describe how changes in skin color may be used as clinical signs of certain disease states and briefly discuss the evolution of skin color. 3. Compare and contrast eccrine and apocrine glands and discuss the significance of these glands in the evolution of the "naked ape." 4. Describe the functional relationship of arrector pili muscles to the hair follicles and the evolutionary significance of these muscles in humans. 5. Describe how the skin accomplishes at least five different functions. 6. Summarize the characteristics of the three major types of skin cancers. 7. Explain why serious burns are life threatening. Describe how to determine the extent of a burn and differentiate first-, second-, and third-degree burns. 8. Describe the interaction between sunlight and vitamin D 3 synthesis. I The Skin [integument (in-TEG- f8e5 u-ment; "covering"] A. Introduction (Fig. 5.1) 1. The body's largest [16% of total body weight], most accessible, familiar and probably most under-appreciated organ system; first line of defense against an often hostile environment; two major components: the cutaneous membrane and the accessory structures [hair, nails, glands] 2. Cutaneous membrane [skin] a. Epidermis : keratinized [ keratin =fibrous protein] stratified squamous epithelium; avascular but innervated * Thick or thin skin refers only to the epidermis, not to overall total skin thickness b. Dermis : fibrous connective tissue; may average more than 4 mm in thickness in some areas; vascular and innervated 3. Subcutaneous tissue [technically not part of the skin proper] a. Also called hypodermis or superficial fascia [FAY-shah]; it forms a connection between the skin and underlying structures; mostly loose fibrous and adipose tissue, but also blood vessels and nerves [I wonder what the target tissue is of a hypodermic needle vs. a intradermal injection?] * Fascia ["band"]: a general term for the fibrous C.T. masses in different locations in the body; fascia binds together the structures of the body with many collagenous fibers arranged irregularly, although under the skin fascia is mostly adipose * Deep fascia: surrounds muscles, blood vessels, & organs B. Epidermis (Fig. 5.2) 1. Cells a. Keratinocytes [ke-RAT-i-n f8e5 o-s f8e5 its; sometimes called "corneocytes"]: protection [90% of epidermal cells; filled with keratin, a tough, fibrous protein and basic structural component of hair and nails] b. Melanocytes : protection [5% of epidermal cells; see below under skin color] c. Merkel cells [discs]: touch [also called tactile epithelial cells] d. Langerhans cells [epidermal dentritic cells] : protection [antigen presenting cells (APCs) of immune system 2. Layers [strata; think "strat um means layer, as in strat...
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This note was uploaded on 01/09/2012 for the course BIO 242 taught by Professor Jimellinger during the Spring '12 term at Bellevue College.
- Spring '12