Integumentary System(Chapter 5)Lecture MaterialsforAmy Warenda Czura, Ph.D.Suffolk County Community CollegeEastern CampusPrimary Sources for figures and content:Marieb, E. N. Human Anatomy & Physiology 6th ed. San Francisco: Pearson BenjaminCummings, 2004.Martini, F. H. Fundamentals of Anatomy & Physiology 6th ed. San Francisco: PearsonBenjamin Cummings, 2004.Amy Warenda Czura, Ph.D.1SCCC BIO130 Chapter 5 Lecture SlidesIntegument = “covering”~16% of body mass: ~2 meter2Composed of:1. Cutaneous membrane A. Epidermis - superficial epithelium B. Dermis - underlying CT w/ blood supply2. Accessory structures A. Hair B. Nails C. Exocrine glandsAmy Warenda Czura, Ph.D.2SCCC BIO130 Chapter 5 Lecture SlidesFunctions:1. Protect underlying tissues from infection, exposure and dehydration2. Excrete salts, water, and organic waste3. Maintain normal body temp(conserve and radiate heat)4. Synthesize Vitamin D3 for calcium metabolism5. Store nutrients (fat)6. Sensory detection:touch, pressure, pain, and tempEpidermis (on handout)Amy Warenda Czura, Ph.D.3SCCC BIO130 Chapter 5 Lecture SlidesAmy Warenda Czura, Ph.D.4SCCC BIO130 Chapter 5 Lecture SlidesThe corrugated border between dermis and epidermis helps bond epidermis to dermis(increased surface area for attachment)In thick skin epidermal ridges show on the surface as fingerprints:function to enhance grippingAmy Warenda Czura, Ph.D.5SCCC BIO130 Chapter 5 Lecture SlidesEpidermis water resistant but not water proof:Insensible perspiration = water loss throughepidermis: ~500ml (1 pint) / day (more ifdamaged, e.g. burn)Callus = thickening of epidermis, due to repeat frictionBlister = separation of epidermal layers orepidermis from dermis, space fills with interstitial fluidSkin ColorPigment based: epidermal pigments and bloodpigments contribute to the color1. Epidermal Pigmentation A. Carotene: yellow-orange, from diet-converted into Vitamin A-localized to epithelium-functions in normal maintenance of epithelia and photoreceptors-excess accumulates in stratum corneumAmy Warenda Czura, Ph.D.6SCCC BIO130 Chapter 5 Lecture SlidesB. Melanin: brown, from melanocytes-for UV protectionMelanocytes: in stratum basale-synthesize melanin from tyrosine (amino acid)-packaged in melanosomes-transferred to cytoplasm of keratinocytes-cluster around top side of nucleus-eventually digested by lysosomesAmy Warenda Czura, Ph.D.7SCCC BIO130 Chapter 5 Lecture SlidesEveryone has ~1000 melanocytes /mm2:-pale people: small melanosomes, present onlyin stratum basale and spinosum-dark people: larger, greater number ofmelanosomes, retained up through stratumgranulosumFreckle = overproduction of melanin fromsingle melanocyteUV exposure:-some needed for Vitamin D3 production-excess = damage (DNA mutation)-fibroblasts → altered CT structure,wrinkles-epidermal cells, melanocytes →cancers:squamous cell carcinomamelanomaAmy Warenda Czura, Ph.D.8SCCC BIO130 Chapter 5 Lecture Slides2. Dermal Circulation: hemoglobin pigment-oxygenated blood = red color, hemoglobin inRBCs, through skin looks pink *vasodilation → skin looks more red *vasoconstriction → skin looks more pale-Cyanosis = low oxygen, blood deep purple,skin appears blue/purple results from low temp, heart failure, asthmaAbnormal skin color:-Jaundice: liver fails to excrete bile,accumulates in skin, yellow-Addison’s Disease: pituitary secretes excessadrenocorticotropic hormone, stimulatesmelanocytes, excess melanin, bronzing-Albinism: genetic mutation in melaninbiosynthesis pathway, lackpigmentation in skin, hair and eyes-Vitiligo: autoimmune disease → destructionof melanocytesAmy Warenda Czura, Ph.D.9SCCC BIO130 Chapter 5 Lecture SlidesVitamin D3 Production:Cells of stratum spinosum and basaleUV energy + cholesterol = Vitamin D3Vitamin D3 used by kidney to synthesize thehormone calcitriolCalcitriol necessary to signal small intestine toabsorb calciumNo VitD → no calcitriol → no calciumabsorption → weak bonesDermis (on handout)Amy Warenda Czura, Ph.D.10SCCC BIO130 Chapter 5 Lecture SlidesCollagen fibers from reticular layer blend intopapillary and subcutaneous layers to attachintegument to body-wrinkles = dermisstretched beyondits elastic capacity,collagen fibers damaged-stretch marks = collagen & elasticfibers torn-collagen & elastinfibers arranged inparallel bundlesaligned to resist theexpected directionof force = lines ofcleavage-cuts parallel to lines ofcleavage will heal fasterand with less scar than those perpendicularAmy Warenda Czura, Ph.D.11SCCC BIO130 Chapter 5 Lecture SlidesDermis highly vascularized: must “feed” itselfand epidermis aboveContusion = bruise, trauma that rupturesblood vessels but does not break skin,blood pools in dermis and must beremoved by phagocytes (slow process)Amy Warenda Czura, Ph.D.12SCCC BIO130 Chapter 5 Lecture SlidesSensory perception in integumentSkin highly innervated for sensory perception,mostly in dermis:1. Tactile discs/Merkel cells-deep layers of epidermis, superficial touch2. Free nerve endings -superficial dermis,pain and temperature3. Tactile/Meissner’s corpuscles -superficial dermis, light touch4. Lamellated/Paciniancorpuscles - deep dermis, pressure and vibrationAmy Warenda Czura, Ph.D.13SCCC BIO130 Chapter 5 Lecture SlidesSubcutaneous Layer a.k.a. Hypodermis-areolar and adipose CT-tightly interwoven with reticular layer ofdermis-not part of cutaneous membrane-stabilizes position of skin while permittingindependent movement of skin andmuscles-children: even layer of adipose-puberty: adipose shiftsmale: neck, arms, abdomen, lower backfemale: breast, buttocks, hips, thighs-no vital organs: safe for “SubQ” injection,vascular for quick absorptionAmy Warenda Czura, Ph.D.14SCCC BIO130 Chapter 5 Lecture SlidesAccessory Structures of the Integument:1. Hair follicles and hair2. Sebaceous glands3. Sweat glands4. NailsAll of these structures are anchored in thedermis but are derived from epidermal tissueHairHuman body: ~2.5million hairs, 75% on bodyEverywhere except: palms, soles, lips, andcertain genitaliaHair itself is dead, but is derived from liveepidermal tissueHair and Hair Follicle Structure (on handout)Amy Warenda Czura, Ph.D.15SCCC BIO130 Chapter 5 Lecture SlidesGlassy MembraneHair MatrixHair follicleAmy Warenda Czura, Ph.D.16SCCC BIO130 Chapter 5 Lecture SlidesAmy Warenda Czura, Ph.D.17SCCC BIO130 Chapter 5 Lecture SlidesShape of the shaft determines feel:-flattened shaft = kinky hair-oval shaft = silky and