CBIO 2200 1nd Edition Lecture 9 Outline of Last Lecture I. Tissue GrowthII. Tissue DevelopmentIII. Stem CellsIV. Tissue RepairV. Tissue Shrinkage (Atrophy) and DeathVI. Programmed Tissue DeathVII. Tissue EngineeringChapter 6I. Integumentary SystemII. Functions of skinIII. The Skin and Subcutaneous TissueIV. Layers of EpidermisOutline of Current Lecture I. The DermisII. The HypodermisIII. Skin ColorCurrent LectureI. The Dermisa. Blood vesselsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.b. Sweat glandsc. Sebaceous (oil) glandsd. Nerve endingse. Dermal papillae – ridges above dermisf. Epidermal ridges – ridges right under skin (makes fingerprints)g. Two layersi. Papillary layer – layer that is closest to epidermisii. Reticular layer – layer under papillary layerh. Stretch marks (striae) – created by the breaking of the collagen fibers and epidermis loses supporti. Hair follicles and nail rootsi. Smooth muscle (piloerector muscles) also called arrector pili – contracts in response to stimuli (responsible for goose bumbs)ii. Eponychium (cuticle) – “Epi” – above; “onychium” – nail; dead epidermis above the nail1. Top layer is epidermis2. Inside is dermisII. The Hypodermisa. Not true layer of skinb. Subcutaneous tissue – adipose tissuec. There is where a lot of medication is put into blood because of blood vessels thatare presentIII. Skin colora. Three pigments contribute to skin colori. Melanin – depends on how much melanin is produced (depends on UV exposure) and how it is dispersed in the cell1. Two forms:a. Eumelanin – brown to black pigmentb. Pheomelanin – red to yellow pigment2. Darker skin = more melanin that is spread out in cell3. Lighter skin = clump in one are of cellii. Hemoglobin – pigment that carries oxygen; red tintiii. Carotene – yellow/orange pigment; concentrates in stratum corneum andsubcutaneous fatb. Colors of diagnostic valuei. Cyanosis – blueness; lack of oxygenii. Erythema – redness; blood flow increaseiii. Pallor – pale; lack of blood flowiv. Albinism – genetic lack of melanin (non-functional tyrosinase allele – important for synthesis of melanin) v. Jaundice – yellowing of skin and sclera; something wrong with livervi. Hematoma (bruise) – clotted bloodIV. Hair and Nailsa. Pilus – another name for hair; pili – plural of pilusi. Stratified squamous epithelium (keratinized)b. Hard keratin in hair and nailsc. Zones of the hairi. Bulb – part that is in contact with blood vessels; receives nutrientsii. Root – the remainder of follicle that is still under skiniii. Shaft – portion of hair above skind. Three layersi. Medulla – contains keratinii. Cortex – flattened cells covering medullaiii. Cuticle – lays over cortex like shingles (conditioner lays shingles down); also contains hard keratine. Structure of the hair folliclei. Outer connective tissue sheathii. Inner Epithelial root sheath – makes up hair follicleiii. Dermal papilla – in bulb; dermis along with connective tissue go up into hair bulbiv. Hair matrix – area right above dermal papillae; where hair has mitotically active cells (where hair grows)f. Hair colori. Brown and Black hair – rich in eumelaninii. Red hair - pheomelaniniii. Blonde hair – eumelaniniv. Gray and white hair – absence of melanin; medulla is replaced by airg. Three kinds of hair grow over the course of our livesi. Lanugo – before we’re born; present at birth; fine hair on skinii. Vellus – replaces lanugo; on hands; fine hair on children and femalesiii. Terminal – some parts of body replace vellus; pubic, eyebrows, eyelash, etc.; longer and courser h. The hair cyclei. Consists of three developmental stages1. Anagen: grow from dermal papillae; 6-8 yearsa. Mature anagen phase 2. Catagen: hair comes away from dermal papillae and becomes “club hair”; 2-3 weeks3. Telogen: dermal papillae will start to ascend which will push hair out of way and a new hair will start to growii. Alopecia – thinning or loss of hair (due to medication, age, male pattern baldness, etc.); once hair comes out, no replacement growsi. Nailsi. Hyponychium – skin immediately under nail; “nail bed”ii. Eponychium – cuticle V. Cutaneous Glandsa. Five types in skini. Merocrine sweat glandsii. Apocrine sweat glandsiii. Sebaceous glandsiv. Ceruminous glandsv. Mammary glandsb. Sweat glandsi. Merocrine (eccrine) sweat glands1. Myo-epithelial cells: muscle-like epithelial cells; squeeze sweat outof ductsii. Apocrine sweat glands: mix with bacteria and give body odor “bromhidrosis” – body odor1. Associated with production of pheromones c. Sebaceous glands – found everywhere except thick glandsi. “Sebum” – oil d. Ceruminous glands – only found in external ear canal; secrete sebum and combine dead epithelial cells which makes cerumen (ear wax)e. Mammary glands – breasts; modified fat tissue; only active once pregnancy has occurred; not glandular until pregnancyVI. Skin cancera. Induced by UV rays of the sunb. Three types:i. Basal cell carcinoma – 1. Most common2. Seldom metastasizes (cells break off and begin growing somewhere else)a. Excision will generally cureb. Easy to cure3. Cells in stratum basaleii. Squamous cell carcinoma – 1. Second most common2. Keratinocytes in stratum spinosum3. Tends to metastasize to lymph nodes4. Excision, unless metastasized then need chemotherapyiii. Malignant melanoma – 1. Skin cancer that arises from melanocytes2. Metastasizes rapidly3. Usually fatal if unresponsive to chemotherapy4. ABCD rule for recognizing malignant melanomaa. Asymmetry b. Border irregularity – uneven edgesc. Color – 2 or more shadesd. Diameter – should be less than 6mm, if over may be malignant5. Clark’s level for diagnosing malignant melanomaa. Level one – only epidermisb. Level two – dermisc. Level three – papillary layerd. Level four – reticular layere. Level five – subcutaneous fat; called “full thickness”c. Generally occur in head and neck areaVII. Burnsa. Leading cause of accidental deathb. Makes you become dehydrated, electrolyte imbalance, and infection are main concernsc. Estimate extent of burns using the rule of ninei. You divide the body up into regions of 9%1. Thorax2. Abdominal3. Arms – front and back4. Legs – front and back5. Head – front and back6. Groin – 1%d. Debridement eschar – dead skin