INTEGUMENTARY SYSTEM

1. INTEGUMENTARY SYSTEM The skin is the largest organ.

2. Skin Functions • Physical barrier • General senses: touch, pressure, pain, temperature • Vitamin D source • Temperature regulation • Excretion of wastes

3. Types of cells: • Keratinocytes • produce keratin • totally replaces epidermis every 25-45 days • Melanocytes • produce melanin • Langerhans • dermal macrophages • Merkel cells • sensory receptors for touch

4. Skin Layers • Epidermis - Stratified squamous epithelium that is keratinized • Dermis - Irregular dense fibrous connective tissue

5. Major Layers of Skin • Epidermis • stratum corneum • outermost • thickest • dead, flaky, dandruff • stratum lucidum • (clear) • stratum granulosum • increased keratinization

6. Major Layers of Skin • Epidermis • stratum spinosum • (prickly layer) • stratum basale • (stratum germinativum) • mitotic division • Contains melanocytes

7. Skin Layers • Dermis • Papillary layer contains: • Dermal papillae • Meissner’s corpuscles (touch receptors) • Reticular layer • Arteries • Veins • Glands • Pacinian corpuscles (pressure receptors)

8. Skin Color • Melanin • Yellowish to reddish-brown to black • Racial differences result from kind and amount of melanin • Freckles: local accumulation of melanin • Melanin increase due to damage from ultraviolet radiation • Excessive exposure to sun damages elastin fibers, depresses immune system, and alters DNA possibly leading to skin cancer

9. Carotene • Yellowish, orange • Accumulation due to diet • Hemoglobin - reddish

10. Color variations • Redness (Erythema) • blushing, fever, inflammation, allergy • Pallor • fear, anger, stress, anemia • Jaundice • yellowish color due to bile; liver disorder • Bronzing • Addison’s disease ; adrenal cortex disorder • Bruises (hematoma) • clotted blood beneath skin

11. Accessory Structures • Sudoriferous (Sweat) Glands • Eccrine glands • covers most of body; especially hands, feet, and head • Eccrine secretion contains water, salts, vitamin C, antibodies, waste (urea, uric acid, ammonia), and lactic acid

12. Accessory Structures • Sudoriferous (Sweat) Glands • Apocrine glands (axial and genital areas) • Apocrine secretions add fatty substances and proteins • Breakdown of aprocrine secretions by bacteria causes body odor • Begin functioning at puberty

13. Accessory Structures • Specialized Sudoriferous (Sweat) Glands • Ceruminous glands - secrete wax • Mammary glands - secrete milk instead of sweat

14. Sebaceous (Oil) Glands • Secrete sebum • softens and lubricates skin and hair • waterproofs • activated by hormones during puberty • Whitehead - gland blocked by accumulated sebum • Blackhead - dried, oxidized sebum • Acne - active inflammation of sebaceous glands • Seborrhea (Cradle cap) - overactive sebaceous glands

15. Hair & Hair Follicles • Structure of hair • Shaft - projects from skin • Root - embedded in skin • 3 layers of ketatinized cells • medulla - core • cortex - surrounds core • cuticle - outermost layer

16. Hair & Hair Follicles • Structure of follicle • Hair bulb - expanded end of follicle • Hair papilla - dermal papilla protruding into hair bulb; supplies nutrients; stimulates growth • Hair matrix - produces hair; active division; older cells pushed to top, increase keratinization & die • Arrector pili -muscle that raises hairs; causes goose bumps

17. Distribution, Types, & Growth of Hair • Vellus - fine body hair of children and females • Terminal - coarse hair of scalp and eyebrows • Growth stimulated by androgens • Affected by nutrition • Average growth rate = 2mm per week • Hair Cycles vary • scalp follicles active approx. 4 yrs • eyebrow follicles active 3-4 months

18. Hair Thinning & Baldness • After 40’s resting cycles lengthen • Hair not replaced as fast as lost • Baldness = alopecia • Male Pattern Baldness • Genetically determined • Sex influenced

19. Nails • Scale-like modifications of epidermis • Structure • Free Edge • Body • Root • Nail Bed - epidermis beneath nail body • Nail Matrix - proximal portion of nail bed • Lunula • Nail folds • Eponychium (cuticle)

20. Skin Disorders • Warts - nonmalignant epithelial growth caused by a virus • Cold sores (fever blisters) • small fluid-filled blisters around lips & mouth • caused by a herpes simplex virus • Acne - inflammation of sebaceous glands • Impetigo - inflamed lesions caused by staphylococcus infection • Decubitus ulcers (bed sores) caused by irritation and inadequate circulation

21. Skin cancers • Most skin tumors benign (ex. Warts) • Basal Cell Carcinoma • least malignant • approx. 30% of caucasians will develop this • 99% cure rate • Squamous Cell Carcinoma • Scaly elevation arising from the stratum spinosum

25. Cutaneous melanoma • Arise from melanocytes • 2 types • melanocarcinoma • malignant melanoma • Irregular growths with variety of pigmentation (brown, gray, black, or blue) • Occur in all age groups, usually in people who sunburn easily • More common in people who get short intense exposure to sunlight. • Survival rate is low. • May begin in regular skin or mole

27. ABCDE rule • A - Asymmetry • B - Border irregularity • C - Color • D - Diameter • E - Elevation

28. ABCD’s of Skin Cancer

32. First-degree burns - involves only epidermis Second-degree burns - involves both epidermis and dermis Third-degree burns - complete destruction of both layers, probable involvement of subcutaneous tissue Burns also classified by the extent of burn area Classification of Burns

33. RULE of NINES Head = 9% Anterior Thoracic = 9% Posterior Thoracic = 9% Anterior Abdomen = 9% Posterior Abdomen = 9% Left Arm = 9% Right Arm = 9% Anterior Left Leg = 9% Posterior Left Leg = 9% Anterior Right Leg = 9% Posterior Right Leg = 9% Genitals = 1% Classification of Burns