2/4/2016 Chapter 16: Skin Find this out on page 650 in your book: What the name for the system that includes skin? How much does our skin weigh? How much surface area does it cover? Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 1 Chapter Goals Name the layers of the skin and the accessory structures associated with the skin. Build medical words using the combining forms that are related to the specialty of dermatology. Identify lesions, signs, and symptoms, and pathologic conditions that relate to the skin. Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 2 1 2/4/2016 Chapter Goals Describe laboratory tests and clinical procedures that pertain to the skin and recognize relevant abbreviations. Apply your new knowledge to understanding medical terms in their proper contexts, such as medical reports and records. Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 3 Introduction ● the skin and its accessory structures (hair, nails and glands) make up the integumentary system of the body ● weighs 8-10 lb ● covers 22 square feet Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 4 2 2/4/2016 Functions of Skin provides protective membrane - guards the deeper tissues against excessive loss of water, salts and heat - protects against pathogens glands lubricate and cool the skin receptor for sensations (pain, temp, pressure and touch) helps maintain body temperature (thermoregulation) Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 5 Anatomy of the Skin Epidermis: outermost, thin cellular membrane - contains keratin Dermis: dense, fibrous, connective tissue layer - contains collagen Subcutaneous tissue (hypodermis): thick, fat- containing tissue Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 6 3 2/4/2016 Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 7 Acessory Organs of the Skin HAIR: cells filled with the hard protein; keratin Hair follicles: shafts that hold the hair Five million hairs on body; 100,000 on head Melanocytes at the root form the color Grow .5 inch (1.3 cm) per month Cutting does not affect growth Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 8 4 2/4/2016 Accessory Organs of the Skin (cont’d) Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 9 Accessory Organs of Skin (cont’d) NAILS: hard keratin plates covering toes and fingers lunula cuticle paronychium Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 10 5 2/4/2016 Accessory Organs of Skin (cont’d) GLANDS: sebaceous and sweat Sebaceous glands secrete oily sebum into hair follicle to lubricate. Sweat glands secrete into pores to moisten and cool. Both are subject to bacterial growth. Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 11 Accessory Organs of Skin (cont’d) Sebaceous gland: Oil secreting gland in the dermis that is associated with hair follicles Eccrine sweat gland: Most numerous sweat producing exocrine gland Apocrine sweat gland. Sweat gland located in the axilla (armpit) and genital areas Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 12 6 2/4/2016 Colors – combining forms ● memorize this table Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 13 Skin Pathology CUTANEOUS LESIONS ● a lesion is an area of abnormal tissue anywhere on the body - it may be caused by trauma or disease crust - collection of dried serum and cellular debris (scab, eczema, impetigo, seborrhea) cyst - thick-walled, closed sac / pouch containing fluid or semisolid material erosion - wearing away of the epidermis (dermoepidermal junction) - occur due to inflammation or injury Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 14 7 2/4/2016 Skin Pathology CUTANEOUS LESIONS fissure - grove or crack-like sore macule - flat lesion < 1cm in diameter (freckles, tattoo marks, flat moles) nodule - solid, round or oval elevated lesion > 1cm in diameter (enlarge lymph node or solid growths) papule - small (< 1cm), solid elevation of the skin (pimples - if confluent called plaques) Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 15 Skin Pathology CUTANEOUS LESIONS polyp - growth extending from the surface of a mucous membrane (type of papule commonly found in nose / sinuses, colon, bladder and uterus) pustule - papule containing pus (small abscess) ulcer - open sore on the skin or mucous membranes (deeper than an erosion) vesicle - small collection (papule) of clear fluid (serum); blister (vesicles form in burns, allergies, dermatitis) Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 16 8 2/4/2016 Skin Pathology CUTANEOUS LESIONS wheal - smooth, edematous (swollen) papule or plaque that is redder or paler than the surrounding skin (often accompanied by itching and are seen in hives, anaphylaxis and insect bites) Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 17 Cutaneous Lesions (p 662) 1. Crust 2. Cyst 3. Erosion 4. Fissure 5. Macule 6. Nodule 7. Papule 8. Polyp 9. Pustule 10.Ulcer 11.Vesicle 12.Wheal Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 18 9 2/4/2016 Signs and Symptoms alopecia: absence of hair where it normally grows alopecia or baldness may be hereditary (male pattern baldness) or it may be caused by disease, injury or treatment (chemotherapy) alopecia areata - autoimmune disease - hair falls out in patches without scarring or inflammation Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 19 Signs and Symptoms ecchymosis: blue-black marks (bruise) on the skin caused by hemorrhages into the skin from injury or spontaneous leaking of blood from vessels Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 20 10 2/4/2016 Signs and Symptoms petechia: small pinpoint hemorrhage smaller versions of ecchymoses - both ecchymoses and petechiae are forms of purpura (bleeding into the skin) Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 21 Signs and Symptoms pruritus - itching symptom associated with most forms of dermatitis arises from stimulation of the nerves in the skin urticaria: acute allergic reaction with red, round wheals on skin commonly due to food allergies (shelfish and strawberries) localized edema occurs as well Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 22 11 2/4/2016 ABNORMAL CONDITIONS acne: papular and pustular eruption of skin with increased production of sebum acne vulgaris (ordinary) is a buildup of sebum and keratin in the pores of the skin Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 23 ABNORMAL CONDITIONS burns: injury to tissue due to heat, chemical, electric shock, lightning or radiation. first-degree burn - superficial epidermal lesions, erythema, hyperesthesia and no blisters second-degree burn (partial thickness) - epidermal and dermal lesions, erythema, blisters and hyperesthesia second degree burn Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 24 12 2/4/2016 ABNORMAL CONDITIONS burns: injury to tissue due to heat, chemical, electric shock, lightning or radiation third-degree burns (full thickness) - epidermis and dermis are destroyed (necrosis) and subcutaneous layer damaged, leaving charred, white tissue third degree burn Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 25 ABNORMAL CONDITIONS cellulitis: diffuse acute infection of skin marked by local heat, redness, pain and swelling abscess formation and tissue destruction can occur without appropriate antibiotic therapy eczema: inflammation of skin with erythematous, papulovesicular lesions caused by allergy chronic or acute atopic dermatitis is accompanied by pruritus treatment usually corticosteriods Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 26 13 2/4/2016 ABNORMAL CONDITIONS exanthematous viral diseases: rash (exanthem) of the skin due to virus examples: rubella (German measles), rubeola (measles) and varicella (chicken pox) Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 27 ABNORMAL CONDITIONS gangrene: death of tissue associated with loss of blood supply ischemia from injury, inflammation, frostbite, diabetes or arteriosclerosis can lead to necrosis followed by bacterial infection and putrefaction impetigo: bacterial inflammatory skin disease characterized by vesicles, pustules and crusted-over lesions contagious pyoderma caused by Staphylococci or Streptococci treatment with systemic antibiotics and cleaning lesions Copyright © 2011, 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. 28 14 2/4/2016 ABNORMAL CONDITIONS psoriasis: chronic recurrent dermatosis marked by itchy, scaly, red plaques covered by silvery gray scales not infectious or contagious but autoimmune - caused by in