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The Integumentary System

The Integumentary System. Chapter 4. Integumentary System. Structure Epidermis Dermis Subcutaneous Functions of the skin. The “Birthday Suit”. Combination of 4 main tissues Epithelial – outer layer Connective – underlies & connects dermis Smooth Muscle – erect hair

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The Integumentary System

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  1. The Integumentary System Chapter 4

  2. Integumentary System • Structure • Epidermis • Dermis • Subcutaneous • Functions of the skin

  3. The “Birthday Suit” • Combination of 4 main tissues • Epithelial – outer layer • Connective – underlies & connects dermis • Smooth Muscle – erect hair • Nervous – sensory receptors • Structure allows it to carry out many functions • Protection, hydration, sensation, color, temperature regulation, etc. • Very durable

  4. Protection Temperature regulation Sensations Storage of chemical compounds Excretion of wastes Synthesis of compounds Determines characteristics Functions of the Skin

  5. Structure of the Skin • 2 principal parts • Epidermis • Dermis • Beneath the Dermis • Subcutaneous

  6. Epidermis • Stratified squamous epithelium • Approximately every month we shed entire skin surface • Consists of keratinocytes

  7. Stratum Germinativum Cuboidal cells Mitosis occurs Stratum Spinosum Germinal cells shrink Cells look spiny Stratum Granulosum Produces keratohyaline & keratin Cells die Stratum Lucidum Found only in thick skinned or calyces areas (hands, feet, elbows, knees) “Clear layer” Filled with keratin Stratum Corneum Multiple dead layers “Cornified” Waterproof Layers of the Epidermis (bottom to top)

  8. Layers of the Epidermis

  9. Variations in Skin Color • Pigments • Melanin • Produced by melanocytes • Protects skin from UV rays • Carotene • Red pigment of “gingers” • Lack of pigment • Albino • Dermal blood supply • “Blushing”

  10. Epidermis & Dermis • Epidermis is avascular (contains no vessels) • Dermis is highly vascular (contains blood vessels) • Epidermis receives nourishment from dermis • Cells furthest away from nourishment die

  11. Dermal Layer • 2 layers • Papillary layer • Reticular layer Connective tissue • Loose Fibrous (collagen firm & elastic) • Adipose • Contains • Blood vessels • Nerves • Glands • Hair follicles

  12. Papillary Layer • Most superficial layer • Loose connective tissue • Surface area increased by papillae • Form fingerprints for grip

  13. Reticular Layer Deeper layer • Dense, irregular connective tissue (collagen) • Contains • Blood vessels • Glands • Deep pressure receptors

  14. Subcutaneous Layer • Loose connective tissue • Packed with adipocytes (fat cells) • Stabilizes position of skin, shock absorber, energy storage/source

  15. Epidermal Appendages • Hair • Glands • Nails

  16. Hair (Pili) • Came with mammals • Embryological development & distribution • Life span of hair • What does hair do for mammals?

  17. Functions of Hair • Protection • Thermoregulation • Sensory • Minor? role in humans • beauty

  18. Hair Structure • Shaft • Superficial • Root • Below surface

  19. Hair Structure • Medulla • Soft core • Cortex • Hard core • Gives hair stiffness • Cuticle • Outermost layer

  20. Hair Develops in Follicles • Location • Deep in dermis • Structure • External root sheath • Internal root sheath • Bulb • Contains matrix • Hair papilla • Contains blood vessels and nerves http://www.tgfolk.net/sites/gtg/tfb-elect.html

  21. Arrector Pili • Smooth muscle attaches to follicle • Raises hairs • Emotional response, cold • Function- traps air

  22. Glands • Sebaceous glands • Connected to hair follicles • Secrete a waxy, oily substance (sebum) • Develop in utero at about 5 months • Secretion increases at puberty

  23. Glands • Sweat glands • Eccrine glands • Found just about everywhere (esp. palms & soles) • Produce “perspiration” • Water, salt, met. wastes http://www.pg.com/science/skincare/Skin_tws_35.htm

  24. Glands • Sweat glands(scent glands) • Called Apocrine sweat glands • Specific type of sweat gland • Found near hair follicles • Axillary & genital regions • Develop at puberty http://www.pg.com/science/skincare/Skin_tws_35.htm

  25. The Skin with Sweat Glands

  26. Nails • Dorsal surfaces of ends of fingers & toes • Primate feature • Grasping

  27. Nail Structure • Nail body • Free edge • Nail root • Matrix • Lunula (moon)

  28. Skin Cancer- Melanoma Squamous Cell Carcinoma Basal Cell Carcinoma

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