CBIO 2200 1nd Edition Lecture 9 Outline of Last Lecture I Tissue Growth II Tissue Development III Stem Cells IV Tissue Repair V Tissue Shrinkage Atrophy and Death VI Programmed Tissue Death VII Tissue Engineering Chapter 6 I Integumentary System II Functions of skin III The Skin and Subcutaneous Tissue IV Layers of Epidermis Outline of Current Lecture I The Dermis II The Hypodermis III Skin Color Current Lecture I The Dermis a Blood vessels These 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 c d e f g II III IV Sweat glands Sebaceous oil glands Nerve endings Dermal papillae ridges above dermis Epidermal ridges ridges right under skin makes fingerprints Two layers i Papillary layer layer that is closest to epidermis ii Reticular layer layer under papillary layer h Stretch marks striae created by the breaking of the collagen fibers and epidermis loses support i Hair follicles and nail roots i 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 nail 1 Top layer is epidermis 2 Inside is dermis The Hypodermis a Not true layer of skin b Subcutaneous tissue adipose tissue c There is where a lot of medication is put into blood because of blood vessels that are present Skin color a Three pigments contribute to skin color i Melanin depends on how much melanin is produced depends on UV exposure and how it is dispersed in the cell 1 Two forms a Eumelanin brown to black pigment b Pheomelanin red to yellow pigment 2 Darker skin more melanin that is spread out in cell 3 Lighter skin clump in one are of cell ii Hemoglobin pigment that carries oxygen red tint iii Carotene yellow orange pigment concentrates in stratum corneum and subcutaneous fat b Colors of diagnostic value i Cyanosis blueness lack of oxygen ii Erythema redness blood flow increase iii Pallor pale lack of blood flow iv Albinism genetic lack of melanin non functional tyrosinase allele important for synthesis of melanin v Jaundice yellowing of skin and sclera something wrong with liver vi Hematoma bruise clotted blood Hair and Nails V a Pilus another name for hair pili plural of pilus i Stratified squamous epithelium keratinized b Hard keratin in hair and nails c Zones of the hair i Bulb part that is in contact with blood vessels receives nutrients ii Root the remainder of follicle that is still under skin iii Shaft portion of hair above skin d Three layers i Medulla contains keratin ii Cortex flattened cells covering medulla iii Cuticle lays over cortex like shingles conditioner lays shingles down also contains hard keratin e Structure of the hair follicle i Outer connective tissue sheath ii Inner Epithelial root sheath makes up hair follicle iii Dermal papilla in bulb dermis along with connective tissue go up into hair bulb iv Hair matrix area right above dermal papillae where hair has mitotically active cells where hair grows f Hair color i Brown and Black hair rich in eumelanin ii Red hair pheomelanin iii Blonde hair eumelanin iv Gray and white hair absence of melanin medulla is replaced by air g Three kinds of hair grow over the course of our lives i Lanugo before we re born present at birth fine hair on skin ii Vellus replaces lanugo on hands fine hair on children and females iii Terminal some parts of body replace vellus pubic eyebrows eyelash etc longer and courser h The hair cycle i Consists of three developmental stages 1 Anagen grow from dermal papillae 6 8 years a Mature anagen phase 2 Catagen hair comes away from dermal papillae and becomes club hair 2 3 weeks 3 Telogen dermal papillae will start to ascend which will push hair out of way and a new hair will start to grow ii Alopecia thinning or loss of hair due to medication age male pattern baldness etc once hair comes out no replacement grows i Nails i Hyponychium skin immediately under nail nail bed ii Eponychium cuticle Cutaneous Glands VI a Five types in skin i Merocrine sweat glands ii Apocrine sweat glands iii Sebaceous glands iv Ceruminous glands v Mammary glands b Sweat glands i Merocrine eccrine sweat glands 1 Myo epithelial cells muscle like epithelial cells squeeze sweat out of ducts ii Apocrine sweat glands mix with bacteria and give body odor bromhidrosis body odor 1 Associated with production of pheromones c Sebaceous glands found everywhere except thick glands i 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 pregnancy Skin cancer a Induced by UV rays of the sun b Three types i Basal cell carcinoma 1 Most common 2 Seldom metastasizes cells break off and begin growing somewhere else a Excision will generally cure b Easy to cure 3 Cells in stratum basale ii Squamous cell carcinoma 1 Second most common 2 Keratinocytes in stratum spinosum 3 Tends to metastasize to lymph nodes 4 Excision unless metastasized then need chemotherapy iii Malignant melanoma 1 Skin cancer that arises from melanocytes 2 Metastasizes rapidly 3 Usually fatal if unresponsive to chemotherapy 4 ABCD rule for recognizing malignant melanoma a Asymmetry b Border irregularity uneven edges c Color 2 or more shades VII d Diameter should be less than 6mm if over may be malignant 5 Clark s level for diagnosing malignant melanoma a Level one only epidermis b Level two dermis c Level three papillary layer d Level four reticular layer e Level five subcutaneous fat called full thickness c Generally occur in head and neck area Burns a Leading cause of accidental death b Makes you become dehydrated electrolyte imbalance and infection are main concerns c Estimate extent of burns using the rule of nine i You divide the body up into regions of 9 1 Thorax 2 Abdominal 3 Arms front and back 4 Legs front and back 5 Head front and back 6 Groin 1 d Debridement eschar dead skin from burn can cause infection e Classified by severity how much of skin is involved i First degree partial thickness burn just epidermis e g sunburn ii Second degree involves part of dermis e g severe sunburn iii Third degree Involvement from epidermis to subcutaneous called full thickness burn f Treating burns with skin grafts and artificial grafts for third degree burns i Graft options 1 Autograft graft