Integumentary System

Integumentary System - Human Anatomy& Physiology Integumentary System Lecture Notes Ziser 2005 1 S kin(In teg u m en tary S ystem considered an

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Unformatted text preview: Human Anatomy & Physiology: Integumentary System, Lecture Notes, Ziser, 2005 1 S kin (In teg u m en tary S ystem ) considered an organ or an organ system body’s largest organ ‡ organ of greatest surface area:15-20 sq ft. (1.5-2 m 2 ) General Functions: 1. protection mechanical chemical bacterial UV desiccation 2. tem perature hom eostasis > te m p ‡ sw eat glands, flushing < te m p ‡ arrector pili, pale 3. excretion affects fluid & electrolyte balance sw e a t g la n d s re le a se : w ater, salts, am m onia oil glands release: lipids, acids 4. sensation touch (light touch, w ind, etc) pressure h e a t cold pain 5. synthesis vitam in D precursor passes through capillaries in skin and light converts it to vitam in D 6. nonverbal com m unication eg. hum ans and other prim ates have m uch m ore expressive faces than other anim als Layers of Skin: epiderm is derm is hypoderms Human Anatomy & Physiology: Integumentary System, Lecture Notes, Ziser, 2005 2 Epidermis stra tifie d squam ous epithelium upper layers de a d , fille d w ith ke ra tin (w a xy p ro te in ) low er layers living cells replaced every 35-45 days subdivided into 5 identifiable layers: a. stratum basale low erm ost layer of epiderm is single cell layer thick only cells that get adequate nutrition and oxygen by diffusion from tissues below actively dividing cells bordered below by basem ent m em brane b. stratum spinosum several layers thick less m itosis fla tte n e d , irre g u la r, spinelike projections [ basale + spinosum = stratum germ inativum ‡ grow ing layers] c. stratum granulosum very thin; 2-3 cell layers thick as cells m ove up from s. b a sa le th e y d ie & g e t fla tte r a n d th in n e r keratinization begins here d. stratum lucidum thin translucent band only found in thick areas of epiderm is: soles of feet palm s of hand e. stratum corneum thickest of all layers; 3/4 th ‘s the thickness of epiderm is 20-30 cell layers thick dead cells com pletely filled w ith keratin w a te r re s is ta n t m ain protection against biological and chem ical assault ta ke s keratinocytes 30-40 days from their form ation in s basale until they flake off of the s corneum cells of epiderm is: Human Anatomy & Physiology: Integumentary System, Lecture Notes, Ziser, 2005 3 1. stem cells ‡ undifferentiated cells found only in deepest layer 2 . keratinocytes ‡ m ost cells in epiderm is synthesize keratin 3 . m elanocytes ‡ also in deepest layer synthesize pigm ent m elanin 4 . M erkel cells ‡ touch receptors, attached to nerve cell 5 . dentritic cells (Langerhans cells) ‡ found in s spinosum and s granulosum are m acrophages that stand guard against toxins, m icro b e s a n d o th e r p a th o g e n s th a t p e n e tra te th e skin ‡ if detected they alert im m une system D e rm is (= h id e ) strong, flexible, connective tissue gives skin its strength and resilience gel-like m atrix contains collagen, elastic and reticular fibers rich in nerves, receptors, blood vessels, lym ph vessels...
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This note was uploaded on 12/04/2010 for the course BIO 130 taught by Professor Pfeiffer during the Spring '10 term at SUNY Rockland.

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Integumentary System - Human Anatomy& Physiology Integumentary System Lecture Notes Ziser 2005 1 S kin(In teg u m en tary S ystem considered an

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