1 Integumentary System

2 Composed of several tissues Maintains homeostasis Protective covering Retards water loss Regulates body temperature Houses sensory receptors Contains immune system cells Synthesizes chemicals Excretes small amounts of waste

3 Skin Cells help produce Vitamin D needed for normal bone and tooth development some cells (keratinocytes) produce substances that simulate development of some white blood cells

4 Layers of Skin Skin is one of the largest organs of the body Epidermis Dermis - “true skin” Subcutaneous layer beneath dermis not part of skin

5 Epidermis lacks blood vessels keratinized thickest on palms and soles ( mm) contains melanocytes which provide melanin rests on basement membrane made of stratified squamous as cells are pushed from the deeper portion, they tend to die

6 Dermis contains dermal papillae binds epidermis to underlying tissues made of irregular dense connective tissue on average mm thick contains muscle cells, nerve cell processes, specialized sensory receptors, blood vessels, hair follicles, and glands

7 Subcutaneous Layer Called “hypodermis” Made of loose connective tissue and adipose tissue insulates Contains major blood vessels

8 Hair Follicles epidermal cells tube-like depression extends into dermis hair root hair shaft hair papilla dead epidermal cells melanin arrector pili muscle – when the muscle contracts, hair is pulled into an upright position (cold temp. or fright activates them)

9 (nerve receptor)

10 Nails protective coverings nail plate nail bed lunula – actively dividing region in the fingernail cuticle – fold of skin over the nail

11 Sebaceous Glands usually associated with hair follicles holocrine glands secrete sebum – prevents the skin from drying out absent on palms and soles

12 Sweat Glands sudoriferous glands – activated by heat, pain, fever and nervousness widespread in skin originates in deeper dermis or hypodermis eccrine glands – respond to elevated body temperature apocrine glands – respond to emotional stress and begin to function during puberty Causes body odor

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14 Regulation of Body Temperature

15 Heat Production and Loss Radiation Primary source of heat loss Infrared heat rays escape from warmer surfaces to cooler surroundings. Conduction Heat moves from the body into the molecules of cooler objects in contact with its surface Ex. Sitting on a cold desk Evaporation Sweat glands secrete sweat to the surface of the skin. As the sweat evaporates, it carries heat away from the surface cooling the skin.

16 Problems in Temperature Regulation Hyperthermia – abnormally high body temperature Hypothermia – abnormally low body temperature

17 Skin Color Genetic Factors (greatest impact on skin color) varying amounts of melanin varying size of melanin granules albinos lack melanin Environmental Factors sunlight (melanocytes help to protect deeper cells from sunlight) UV light from sunlamps X-rays All of the above factors darkens melanin Physiological Factors dilation of dermal blood vessels constriction of dermal blood vessels accumulation of carotene jaundice - indicator of liver malfunction

18 Healing of Cuts Blood escapes from the dermal blood vessels. Platelets begin sticking together to form a clot. The blood clot and dried tissue fluid form a scab. Fibroblasts migrate to the injury site and produces new connective tissue.

19 Healing of Burns First degree burn – superficial partial-thickness Second degree burn – deep partial-thickness Third degree burn – full-thickness autograft - using burn victims own skin that hasn’t been damaged homograft - using cadaver skin from a skin bank various skin substitutes Amniotic membrane Artificial membranes of silicone, polyurethane, or nylon

20 Healing of Burns First degree Superficial, skin red and dry Involves only epidermis Rx – cold water Heals in one week (example: sunburn) Second degree Epidermis and dermis Pain, swelling, redness, and blistering Subject to infection Rx – pain medication, dry sterile dressing Healing within two weeks Third degree Epidermis, dermis, and subcutaneous layers (full thickness) Loss of skin, blackened skin May be life threatening Rx – prevention of infection, fluid replacement, skin grafting

21 Rule of Nines

22 Burn Victim 002/oct/texas_dwi/index.htmlhttp:// 002/oct/texas_dwi/index.html

23 Don’t forget about Stems Test 2 Tomorrow and your Skin Quiz Friday!

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25 Common Skin Disorders Acne –Disorder of sebaceous glands –Sebum plugs pores and area fills with leukocytes (white blood cell) –Also, blackheads, cysts, pimples and scarring Albinism – absence of melanin Alopecia – baldness Athlete’s foot –Contagious fungal infection –Usually contracted in public baths and showers –Rx – antifungal agents

26 Common Skin Disorders Acne Alopecia Albinism Athlete’s Foot

27 Common Skin Disorders Boils (carbuncles) –Painful, bacterial infection of hair follicle or sebaceous glands –Rx – antibiotics, excision and drainage of affected area Dermatitis –Non-specific skin inflammation –Rash – reaction to soap, plants, etc. –Skin blotches – caused by stress Eczema –Acute or chronic inflammatory skin disease –Skin dry, red, itchy and scaly –Rx – remove cause, hydrocortisone to help alleviate symptoms Excoriation - abrasion

28 Common Skin Disorders Boil Dermatitis Eczema Excoriation

29 Common Skin Disorders Herpes –Herpes simplex I Viral Fever blister or cold sore –Shingles (herpes zoster) Viral infections of nerve endings On chest or abdomen, accompanied by severe pain Impetigo –Acute, inflammatory and contagious –Seen in babies and young children –Caused by staphylococcus or streptococcus –Vesicles that rupture and develop distinct yellow crusts

30 Common Skin Disorders Herpes Simplex IShingles Impetigo

31 Common Skin Disorders Pruritis - itching Psoriasis –Chronic inflammatory skin disease –Dry reddish patches covered with silvery-white scales Ringworm –Contagious fungal infection –Raised, itchy circular patches with crusts Scabies –Communicable – transmit from one person to another –Severe itching –Mite burrows in skin, lays eggs, eggs hatch

32 Common Skin Disorders Scabies Ringworm Pruritis Psoriasis

33 Common Skin Disorders Skin cancer –Associated with exposure to sun (UV rays) –Most common type of cancer in people –Skin cancer cells are most likely to occur from nonpigmented epithelial cells Basal cell carcinoma (Cutaneous carcinoma) –Occurs mostly in middle-aged people who have a light complexion and work or plays outdoors –Most common, least malignant –Usually on face –Rx – surgical removal or radiation Squamous cell carcinoma –Mostly scalp and lower lip –Grows rapidly, metastasizes to lymph nodes –Rx – surgical removal or radiation –Prognosis good with early diagnosis

34 Common Skin Disorders Basal Cell Carcinoma Squamous Cell Carcinoma

35 Common Skin Disorders Melanoma –Malignant –Occurs in melanocytes –Metastasizes to other areas quickly –Brown or black irregular patch that occurs suddenly –Change in existing wart or mole may indicate melanoma –Rx – surgical removal of melanoma and surrounding area and chemotherapy

36 Common Skin Disorders Melanoma

37 Common Skin Disorders Skin lesions –Pustule – small collection of pus in the top layer of skin –Tumor –Ulcer (superficial and decubitus – lying down) –Vesicle Urticaria (hives) –Itchy wheals or welts –Usually allergic reaction to drugs, food, etc. –Rx – avoid allergen Warts (verrucae) –Caused by virus –Some disappear spontaneously, others removed with liquid nitrogen, chemicals, or laser

38 Common Skin Disorders Urticaria Warts

39 Life Span Changes Skin becomes scaly Age spots appear Epidermis thins Dermis becomes reduced Loss of fat Wrinkling Sagging Sebaceous glands secrete less oil Melanin production slows Hair thins Number of hair follicles decrease Nail growth becomes impaired Sensory receptors decline Body temperature unable to be controlled Diminished ability to activate Vitamin D

40 Clinical Application Acne Vulgaris most common skin disorder sebum and epithelial cells clog glands produces whiteheads and blackheads (comedones) anaerobic bacteria trigger inflammation (pimple) largely hormonally induced Androgens (hormone) stimulate sebum production treatments include antibiotics, topical creams, birth control pills