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43 Cards in this Set
- Front
- Back
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Cutaneous membrane
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contains the skin, which a protective barrier from environmental damage
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Skins main function
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protects against pathogens and holds things together
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Largest organ
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skin,
-16% of weight 22 sq ft 4.5 - 5 kg |
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Thickest & thinnest
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Heel is thickest, 4 mm thick
eyelids are thinnest, .5 mm |
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epithelial tissues (5)
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Continuous turn overs, growing from bottom and up.
1. Basale 2. Spinosum 3. Stratum Granulosum 4. Stratum Lucidum 5. Stratum Corneum |
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1. Stratum Basale
aka stratum germinativum |
-deepest layer of epidermis
-single cubodial/columnar -all karyocytes w HUGE nucleus (NOOOO! keratin) -stem cells present -tonofilaments -HPV affects this layer (keratin occurs early) -Skin graphs (epi to basale) |
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Tonofilaments in basale
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cytoskeleton for strength and flexibility, connected through desmosomes; only going through 1 layer. Irregular to stretch in different ways.
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2. Stratum Spinosum
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-8-10 layers of Keratinocytes (thorn looking b/c tonofilaments)
-Melanocytes ONLY found in this layer |
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Tonofilaments in Spinosum
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Move through a bunch of layers for strength and flexing. They dehydrate and get pulled so they look thorny
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3. Stratum granulosom
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-3-5 layers of flat keratinocytes, 1/2 dead, 1/2 alive b/c apotosis
-every cell entering this layer must die, all dead after |
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Apotosis
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Where keratin occurs because the tonofilaments are converted to keratohyalin which converts to keratin (process of keratinization); occurs in 3rd layer... granulosome
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The top two layers of the skin are ______
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dead
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2 layers of the skin
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Epidermis and dermis
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Epidermis
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what we see on the outside, constantly sheds. Have Keratinized Stratified squamous cells
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Keratinized Stratified Squamous
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4 types of cells in Epidermis
-Keratinocytes (90%) that make keratin -Melanocytes (8%; color) -Longerhand cells (immune SKIN cells ONLY); Antigen presenting cell -Morkel Cells that line sensory receptors to amplify sensation of touch and send to the nerve |
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System with the most Morkel cells
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Reproductive system has the most, fingers second.
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Skin Color
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-Melanin (2 types) give skin color but mostly hair
-Hemoglobin -Keratin -Moles |
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Melanin (2 types)
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Hair color
-phelomelanin - yellow to red -eumelanin - brown to black |
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Hemoglobins
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for oxygen trnasport but also color
-pink to red if oxygen bound -blue if no oxygen |
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Keratin
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-precursor for vitamin A
-protein for strength |
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Moles from melanocytes
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-form from 1 single cell
(1 mole from 1 melanocyte) -benign growth, not cancer -everyone has same number of melanocytes -not about number, about the pigment being made |
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Melanocytes conditions
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-Albinism (cant make melanin); albinos
-insomnia - no melanin = no internal clock -Vitilego - Affects blacks, parts of melanocytes cant make melanin = no color |
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Dermis layer with tattoos
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hips back and upper arms are the thickest dermal layers; most tattoos
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Dermis layer
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-thickest, below epidermis
-has capillaries, collagen and elastic fiber, involuntary muscles, nerve ends, lymph vessels, hair follicles, sudoriferous glands (sweat), and sebacous glands (oil) |
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Cells in the dermis
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Fibroblasts, macrophages, and adipocytes
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Striae
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-stretch marks
- collagen pulled too far, cant return -blocks elasticity |
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Reticular fibers in the dermis
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give the lines of cleavage in hands in feet
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Epidermal ridges
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give fingerprints
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Sebacous glands
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-glands to secrete sebum (oil)
-9:10 in hair follicles -contain triglycerides, cholesterol, ions, proteins and inorganic salts |
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Sebum
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-oil with a low ph to prevent bacteria = no growth
-prevents hair from drying -water retention prevention -keeps skin soft -prevents microbe colunization |
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Blocked sebaceous glands
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sebum gets clogged, dries out from the air and turns black = blackhead. Infected becomes pimple. Squeezing occurs craters. Best to clean.
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2 regions of the dermis
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Papillary region, reticular region
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Papillary region
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1/5 thick contains aerolar tissue with think collagen and elastic fibers
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Reticular regions
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-NO reticular connective tissue
-Largest portion of the epidermis -has dense irregular tissues of collagen and elastic fibers -below the papillary -weblike structures -for elasticity and extensibility -shows hydration -pull skin - no recoil - dehydrated |
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Thermoregulation of the dermis
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-sweat
-blood reservoir (8-10% of all blood in the vessels), injury -protection from microbes infection, abrasion, heat and chemicals -Tactile sensations -helps with secretion and absorbtion -Vitamin D sysnthesis |
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Tactile sensations
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-cutanous sensations of pain, pressure, vibration, tickle, sense of touch
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Vitamin D
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precursor already in the skin, the suns UV light activates it
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Acne
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-inflammation of the sebacous gland
-bacteria sets up colonization -connective tissues form around sebacous glands in infection to protect but becomes displaced and creates pressure -cysts then form (pimples) -cystitis; cystic acne is bacteria that causes it |
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3-4 million Sweat glands; 2 types
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-Eccrine & Apocrine
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Eccrine
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-secrete sweat out to the reticular and coil
-most common -forehead, palms, feet -NOT lips, nailbeds, penis, clit or ear drums = no sweating -sweat made of ions, ammonia, urea, glucose and water to eliminate waste -ions are charged -sweat has lactic acid, uric acid, and amino acid |
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Apocrine
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-Not as common
-Tubular coiled gland -most common spots in armpit, groin, areolar areas (nipples) and beards -activate at puberty |
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Ceruminous gland
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-MODIFIED SWEAT GLAND
-not a sweat gland -makes earwax -qtips push in wax, cause cilia to step moving = loss of hearing -need earwax to pretect infection and for the ear drum cilia |
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Subcutaneous Fascia
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innermost layer of the skin with elastic and fibrous connective tissue and fatty tissue. Attaches to the muscles
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