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Unformatted text preview: Chapter 5: The Integumentary System
Bonnie S. Gunn The Integumentary System Skin Epidermis Outermost layer (may be keratinized) Dermis Connective tissue Hypodermis Adipose and Areolar tissue Composes 9-11 lbs. (~7%) body weight Functions of the Integumentary system Protection Chemical, physical, mechanical Temperature regulation Cutaneous sensation Metabolic functions Synthesis of Vitamin D Blood reservoir Holds 5% of blood volume Excretion Some nitrogen wastes lost in sweat Cells of the Epidermis Keratinocytes Keratin: Protein for protection Melanocytes Melanin: Protein that protects against UV radiation Merkel Cells Associated with sensory nerve for touch Langerhan's cells From bone marrow: Activate macrophages in immune system (star shaped) Diagram showing the main features in epidermis of thin skin Thick skin (palms, fingertips, soles of feet) Thin skin (no lucidum And thinner layers, rest of body) Layers:
Stratum Corneum cornified Stratum Lucidum clear layer only in thick skin Stratum Granulosum keratinizing Stratum Spinosum melanin, etc Stratum Basal germinativum Skin structure: Dermis and Epidermis Dermis Strong, flexible connective tissue Two Layers Papillary: Areolar connective tissue Reticular: Dense irregular connective tissue Dermal ridges-epidermal ridges-finger prints Skin color Dependent on the amount of Melanin present Freckles: Accumulation of melanin Other pigments of the body Carotine: Carotenoids, (Chromophores)
reds and yellows Xanthophores: silvers Melanophores: Browns and blacks Structural pigments Bound pigments Refractile pigments Color Changes in Skin Redness (erythmia): Blushing, inflammation, etc Pallor (blanching): Low blood pressure, fear, emotional stress Jaundice: Yellow, liver disorder where bile stored in tissues Bronzing: Addison's disease, hypofunciton of the adrenal cortex Bruising: Black and blue, hematomas from blood clotted under skin Types of glands Sweat Eccrine: common sweat glands, duct opens to a pore Apocrine: ducts empty to hair follicles Ceruminous: Apocrine secreting earwax Sebaceous (oil glands) Holocrine: secrete sebum (oil). Has a bactericidal function Cutaneous glands Structure of Hair Made of hard and soft keratin Outermost cuticle covering Pigments by melanocytes Red hair: tricosiderin iron pigment Gray or white hair: lack of melanin,
replaced with air bubbles in the shaft Structure of a hair and hair follicle Structure of a hair and hair follicle Common Hair Disorders Alopecia Thinning of hair (both sexes) Male pattern baldness genetically determined, in response to rising testosterone levels Other modifications of the epidermis Cuticle nail formed from the epidermal layers Structure of a nail: surface view Skin Cancer Basal cell carcinoma proliferation of the stratum basal; 99% curable by surgery Squamous cell carcinoma proliferation of the keratinocytes of the stratum spinosum; likely recovery with surgery Melanoma only 5% of cases, but increasing rapidly (3-8% per year!). Metastasizes rapidly. Deadly if over 4mm thick. Melanoma detection ABCD(E) rule A: Asymmetry sides of mole do not match B: Border Irregularity indentations on lesion borders C: Color several colors (brown, blue, black, even red) D: Diameter Pencil eraser size in diameter E: Elevated Rises above skin level Estimating the severity and extent of burns Severity 1st degree epidermis damaged 2nd degree Epidermis, dermis, with blistering 3rd degree Epidermis, dermis, hypodermis destroyed Danger: 10% 3rd degree 25% 2nd degree 3rd degree on hands, face, or feet. Possible respiratory problems due to swelling The End ...
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