The Integumentary System

1. The Integumentary System

2. The Integumentary System • Integument is__________ • Skin and its __________make up the integumentary system • A fatty layer (_________) lies deep to it • Two distinct regions • __________ • __________

3. Functions of skin • ____________ • Cushions and insulates and is waterproof • Protects from chemicals, heat, cold, bacteria • Screens UV • Synthesizes __________ with UV • Regulates _______ _________ • Prevents unnecessary ________ loss • __________ reception (nerve endings)

4. Epidermis • Keratinized stratified squamous epithelium • Four types of cells • __________ – deepest, produce keratin (tough fibrous protein) • __________ - make dark skin pigment melanin • ___________– associated with sensory nerve endings • ____________ cells – macrophage-like dendritic cells • Layers (from deep to superficial) • Stratum _______ or germinativum – single row of cells attached to dermis; youngest cells • Stratum _________ – spinyness is artifactual; tonofilaments (bundles of protein) resist tension • Stratum __________ – layers of flattened keratinocytes producing keratin (hair and nails made of it also) • Stratum ___________ (only on _______ and _______) • Stratum ____________ – horny layer (cells dead, many layers thick) (see figure on next slide)

5. Epithelium: layers (on left) and cell types (on right)

6. Remember… • Four basic types of tissue • ___________ – epidermis just discussed • ____________ tissue - dermis • __________ tissue • __________ tissue

7. Dermis • Strong, _________ connective tissue: your “hide” • _______: fibroblasts, macrophages, mast cells, WBCs • Fiber types: ________, _______, reticular • Rich supply of ________ and ________ • Critical role in _________ regulation (the vessels) • Two layers (see next slides) • ___________ – areolar connective tissue; includes dermal papillae • ____________ – “reticulum” (network) of collagen and reticular fibers

8. *Dermal papillae *Dermis layers * *

9. Epidermis and dermis of (a) thick skin and (b) thin skin (which one makes the difference?)

10. Fingerprints, palmprints, footprints • Dermal __________ lie atop dermal ridges • _________ the overlying epidermis into epidermal __________ • Are “_______ _________” because of sweat pores • _____________ determined _____________ creases • Deep dermis, from _____________ folding Fibers • __________: strength and resilience • Elastic fibers: stretch-recoil • ______________: stretch marks • ____________ lines (or lines of cleavage) • The direction the bundles of fibers are directed The dermis is the receptive site for the pigment of tattoos

11. Hypodermis • “Hypodermis” (Gk) = _________ the skin • “Subcutaneous” (Latin) = ________ the skin • Also called “_________ _________” “fascia” (Latin) =band; in anatomy: sheet of connective tissue • ______ tissue which stores fat and anchors skin (_______ tissue and _________ cells) • Different patterns of accumulation (male/female)

12. Skin color • Three skin pigments • ________: the most _________ • _________: from ________ and _____ _____ • _________: the ______ of light skin • _______ in granules passes from ________ (_____ number in all races) to keratinocytes in stratum basale • _________ by lysosomes • _________ in color • Protection from UV light vs vitamin D?

13. Skin appendages • Derived from epidermis but ______ into dermis • Include • Hair and _____ follicles • __________ (oil) glands • _________ (sudoiferous) glands • Nails

15. Nails • Of hard __________ • Corresponds to ________ and _______ • Grows from nail _______

16. Hair and hair follicles: complexDerived from epidermis and dermisEverywhere but ______, ______, ______, parts of _______ *“arrector pili” is smooth muscle * Hair bulb: epithelial cells surrounding papilla Hair papilla is connective tissue________________

17. Functions of hair • _______ – less in man than other mammals • Sense _______ touch of the skin • _______ - scalp • Parts • ________ imbedded in skin • ________ projecting above skin surface • Make up of hair – ______ _______ • Three concentric layers • _________ (core) • __________ (surrounds medulla) • __________ (single layers, overlapping)

18. Types of hair • _______: fine, short hairs • __________ hairs • __________: longer, courser hair • Hair growth: averages 2 mm/week • _______: growing • Resting phase then shed • Hair loss • Thinning – age related • Male pattern baldness • Hair color • _______ of melanin for black or brown; ________ form of melanin for red • _________: _______ melanin and ____ ______ in the medulla • ____________ determined though influenced by hormones and environment

19. Sebaceous (oil) glands • Entire body except ______ and ________ • Produce _________by holocrine secretion • Oils and lubricates

20. Sweat glands • Entire skin surface except ______s and part of ______ genitalia • Prevent overheating • _____ cc to _____ (is mostly water) • Humans most efficient (only ______ have) • Produced in response to _____ as well as ______

21. Types of sweat glands • Eccrine or merocrine • Most numerous • True sweat: 99% water, some salts, traces of waste • Open through pores • Apocrine • Axillary, anal and genital areas only • Ducts open into hair follices • The organic molecules in it decompose with time - odor • Modified apocrine glands • Ceruminous – secrete earwax • Mammary – secrete milk

22. Disorders of the integumentary system • Burns • Threat to life • ________ loss of body fluids • ___________ and fatal _________ shock • Infection • Types • First degree – _______: redness (e.g. _______) • Second degree – _______ and upper _____: ______ • Third degree - full thickness • Infections • Skin cancer

23. Burns First-degree (epidermis only; redness) Second-degree (epidermis and dermis, with blistering) Third-degree (full thickness, destroying epidermis, dermis, often part of hypodermis)

24. Critical burns Estimate by “rule of 9’s” • Over ____ of the body has ________ burns • ______ of the body has second-degree burns • Third-degree burns on _____, _____, or _____

25. Tumors of the skin • Benign, e.g. warts • Cancer – associated with UV exposure (also skin aging) • _______ keratosis - premalignant • ______ cell - cells of stratum basale • _______ cell - keratinocytes • _______ – melanocytes: most dangerous; recognition: • A - Asymmetry • B - Border irregularity • C - Colors • D - Diameter larger than 6 mm

26. Skin Cancer Sqaumous cell carcinoma Basal cell carcinoma Melanoma