Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Memmler’s The Human Body in Health and Disease 11 th edition Chapter 6 The Skin in Health and Disease

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Integumentary System Skin and associated structures form integumentary system

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Structure of the Skin Skin consists of two layers Epidermis –Strata Dermis –Blood vessels, nerve endings, and glands

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Cross section of the skin.

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Epidermis Surface portion of the skin Stratum basale or stratum germinativum Stratum corneum

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Dermis Contains most of the accessory structures of the skin Blood vessels Nerves Sweat glands Oil glands Hair Dermal papillae

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Subcutaneous Layer Connects the skin to the surface muscles Loose connective tissue Adipose (fat) tissue Blood vessels Nerves and nerve endings

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Accessory Structures of the Skin Some structures of the integumentary system protect the skin and have some more generalized functions as well

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Sebaceous (Oil) Glands Produce a variety of secretions Sebum Vernix caseosa Eye lubrication

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Sudoriferous (Sweat) Glands Located in the dermis and subcutaneous tissue Eccrine type sweat glands Apocrine sweat glands Ceruminous glands Ciliary glands Mammary glands

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Hair Composed mainly of keratin and is not living Hair follicles Melanocytes Arrector pili

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Portion of skin showing associated glands and hair. ZOOMING IN How do the sebaceous glands and apocrine sweat glands secrete to the outside? What kind of epithelium makes up the sweat glands?

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Nails Made of keratin produced by cells that originate in the outer layer of the epidermis Nail root Nail plate Nail bed Lunula Cuticle

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Nail structure.

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Functions of the Skin Four major functions Protection against infection Protection against dehydration (drying) Regulation of body temperature Collection of sensory information

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Protection Against Infection Intact skin forms a primary barrier against invasion Interlocking pattern resists penetration Shedding removes pathogens Protects against bacterial toxins Protects against some harmful environmental chemicals

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Protection Against Dehydration Skin prevents water loss by evaporation Keratin in the epidermis Sebum release from the sebaceous glands

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Regulation of Body Temperature Loss of excess heat and protection from cold are important functions of the skin Constriction of blood vessels Dilation of blood vessels Evaporation of perspiration

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Collection of Sensory Information Skin has many nerve endings and other special receptors Free nerve endings Touch receptors (Meissner corpuscle) Deep pressure receptors (Pacinian corpuscle)

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Other Activities of the Skin Absorption of substances such as medications Excretion –Water –Electrolytes –Wastes Manufacture of vitamin D

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Observation of the Skin Skin attributes can indicate a serious systemic disorder

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Color Factors that influence skin color Amount of pigment in the epidermis –Melanin –Carotene Discoloration –Pallor: pale skin, reduced blood flow –Flushing: redness, as in fever –Cyanosis: bluish color of skin; lack of oxygen in blood –Yellow skin: jaundice, bilirubin in blood; carotenemia from excessive intake of carrots or other deeply colored vegetables

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Lesions Any wound or local damage to tissue Surface lesions –Macule –Papule –Vesicle –Pustule Deeper lesions –Excoriation –Laceration –Ulcer –Fissure

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Burns Categorized by Depth of damage –Superficial partial-thickness –Deep partial-thickness –Full-thickness Amount of body surface area (BSA) involved –Rule of nines –Lund and Browder method

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Tissue Repair Wound healing Occurs only in areas with actively dividing cells –Epithelial tissues –Connective tissues –Minimally in muscle and nervous tissue Is affected by –Nutrition –Blood supply –Infection –Age

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Effects of Aging on the Integumentary System Changes in Skin Tissues Pigment Hair Sweat glands Circulation Fingernails and toenails

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Care of the Skin Proper nutrition Adequate circulation Regular cleansing –Removes dirt and dead skin –Sustains slightly acid environment to inhibit bacteria Protection from sunlight –Exposure to UV light causes genetic mutations in skin that can lead to cancer, and causes premature aging.

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Skin Disorders Range from superficial to deep-seated

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Dermatitis Inflammation of the skin Dermatosis is any skin disease Atopic dermatitis

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Psoriasis Chronic, recurrent overgrowth of epidermis Sharply outlined red (erythematous) areas Flat areas (plaques) covered with silvery scales A hereditary pattern sometimes present Immune disorder may be involved

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Cancer Skin cancer is most common form of cancer in the United States Basal cell carcinoma Squamous cell carcinoma Melanoma

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Acne and Other Skin Infections Acne –Sebaceous glands disease Impetigo –Staphylococcal or streptococcal origin Viral infections –Herpes simplex virus –Herpes zoster virus (shingles) –Human papillomavirus (HPV) (wart or verruca) Fungal infections –Tinea or ringworm

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Alopecia (Baldness) Factors that affect baldness Heredity, aging, and male sex hormones (male pattern baldness) Systemic disease Drugs

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Allergy and Other Immune Disorders Often involve the skin Allergy—reaction to a substance Autoimmune disorders—reaction to one’s own tissues –Pemphigus –Lupus erythematosus –Scleroderma

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Pressure Ulcers Skin lesions that appear where the body rests on skin that covers bony projections. Also known as decubitus ulcers or bedsores