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50 Cards in this Set
- Front
- Back
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What are the functions of the skin?
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protection
water/temp regulation sensory VIt D production Lipid soluble drug absorption (topical steroids) contributes to overall homeostasis by regulating and protecting body and playing main role in sensory |
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What is some qualities of skin structure?
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16 % body weight, 2 sq meters, 4.5-5 kg
thinnest on eyelids; thickest on heels (avg 1-2 mm) 3 layers: epidermis - thinner, epithelial tissue dermis - thicker, connective tissue hypodermis - subQ layer, fat and areolar tissue, attaches to skin and underlying tissues |
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What are the major cells in the Epidermis?
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Keratinocytes:
-90 %, 4-5 layers -produces protein keratin which protects tissues from microbes, heat and water loss -produce lamellar granules which are waterproofing agents and inhibit entry of foreign materials Melanocytes: -8%, from ectoderm -produce pigment melanin which is yellow-red or brown-black pigment absorbs UV light -transfer melanin to keratinocytes Langerhans cells: -from red blood marrow and migrate to epidermis -immune cells, damaged by UV light Merkel Cells: -least numerous, deepest layer -sensory receptors for touch along with merkel disc |
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What are characteristics of Stratum Basale?
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known as stratum germinativum
deepest layer made up of single row of cuboidal or columnar cells some are stem cells (produce new keratinocytes) have melanocytes and merkel cells in them contain tonofilaments which attach to desmosomes desmosomes bind cells of this layer with each other, with stratum spinosum and with hemidesmosomes hemidesmosomes attach keratinocytes with basement membrane bet w/ epidermis and dermis |
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What are characteristics of Stratum Spinosum?
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superficial to stratum basale
8-10 layers of keratinocytes spine like processes have desmosomes contain melanocytes and langerhans cells |
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What are characteristics of Stratum Granulosum?
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3-5 layers of keratinocytes which may undergo apoptosis
contain keratohyalin granules which convert tonofilaments --> keratin lamellar granules --> release water repellant sealant marks transition between active cells below and dead cells above |
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What are characteristics of Stratum Lucidum?
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only in thick skin
3-5 layers of clear, flat, dead keratinocytes packed w/ keratin filaments |
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What are characteristics of Stratum Corneum?
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25-30 layers of dead, flat keratinocytes packed with keratin filaments
shed and replaced by deeper strata skin friction causes abnormal thickening called callus |
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How does the epidermis grow?
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new cells move from basale layer to top
accumulate more and more keratin (keratinization) and lose more and more cell organelles and nucleus and become dead most metabolically active = stratum basale, nearest to blood vessels for nutrients 4 weeks to grow 0.1 mm epidermal growth factor (EGF) responsible for stratum basale to increase activity when outer layers of epidermis are stripped away shed from scalp is called dandruff |
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What are skin grafts?
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transfers patch of healthy skin from a donor to cover wound
surgical procedure to provide temporary covering skin regeneration is not possible if stratum basale or stem cell destroyed by injury, this is where skin grafts come into play |
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What are the types of skin graft?
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split-thickness:
-most common -takes 2 top layers from donor (epidermis and superficial dermis) -donor site = medial side of thigh or arm full-thickness: -takes entire thickness of skin from donor (includes muscles and blood supply sometimes) -donor site = back or abdominal wall muscles and skin composite: -wounds in bone, tendon, cartilage, or loss of muscle -ex. nose construction these two long lasting: autograft = skin from same person isograft = identical twin short lasting before body rejects: allograft = from another human (7-10 days) xenografts = from animals, usually pigs (3-5 days) if superfical allo and xenograft can provide enough protection to allow skin to regenerate on its own apligraft and transite = foreskin of circumsized infants autologous skin transplantation = keratinocytes cultured to produce thin sheet to cover burn |
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What is Psoriasis?
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autoimmune chronic, non-infective and common disorder
appears as thick, red, silvery, scaly patches psoriatic arhritis = 30 % people with psoriasis associated with conditions such as diabetes, heart disease, obesity 7.5 mil Americans have it |
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What are the types of Psoriasis?
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plaque, guttate, inverse, pustular, and erthyrodermic
plaque (most common) appears as raised red lesions covered with white silvery buildup of dead cells called scales occurs when immune system sends faulty signal to speed up division of keratinocytes and move them quick from basale to corneum shed prematurely in 7-10 days or build up to form lesions forms flaky scales at surface (usually knee, elbows, and scalp) |
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What are characteristics of the dermis?
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CT below epidermis
fibroblasts, macrophages, and adipocytes contain blood vessels, nerves, hair follicles, sweat and sebaceous glands essential for survival of epidermis because epidermis is not vascularized fibers have great tensile strength and and elasticity due to presence of CT Leather is from dermis |
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What are the regions of Dermis?
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Papillary (superficial):
-areolar CT (elastic and collagen) -dermal papilla (finger-like) -papilla contain capillary loops, meissners corpuscles (touch), free nerve endings (temp, pain, tickle & itch) Reticular (deep & 4/5 of dermis): -dense irregular CT (fibroblasts, collagen, elastic provide strength, extensibility, and elasticity) -attached w/ subcutaneous layer -hair follicles, sweat and sebaceous glands between irregular collagen |
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What are Striae and Lines of Cleavage?
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striae - slight tears in dermis due to extreme stretching as red or silvery white streaks (pregnancy or obesity)
lines of cleavage - "tension lines" indicating direction of collagen fibers impt for plastic surgeons |
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What are epidermal ridges?
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surface of palms, fingers, soles, and toes make ridges and grooves
form during 3-4 months of fetal life as downward projections of epidermis into dermal papillae (loops and whorls) increase friction and grip fingerprints - sweat and epidermal ridges, serve as basis for identification because genetically determined together dermal papillae with epidermal ridge strengthen skin against shearing forces |
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What is Dermatoglyphics?
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study of pattern of epidermal ridges
dermis impt source of nutrition for overlying epidermis |
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How is skin color determined?
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determined by three pigments:
melanin - yellow/red (pheomelanin) or brown/black (eumelanin) pigment produced by melanocytes (located mostly in epidermis, absorbs UV) # of melanocytes same in all people, differences in skin color due to amount of pigment (melanin) produced and transferred to keratinocytes age spots and freckles are places of accumulation of melanin mole or nevus = overgrowth of melanocyte |
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How is melanin synthesized?
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Melanocytes synthesize melanin from AA tyrosine in a melanosome by enzyme tyrosinase
UV light increases production of melanin and gives tan to protect against radiation |
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What are Carotene and Hemoglobin?
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Carotene:
-yellow orange pigment found in stratum corneum, dermis, and subcutaneous layer -precursor for Vit A (forms pigment for vision) -gives orange color in skin (light skinned people) when deposited under skin Hemoglobin: -pink to red color in skin -located in erythrocytes flowing through dermal capillaries |
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What is Albinism?
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inherited (recessive) inability to produce melanin
affects mammals, fish, birds, reptiles, and amphibians have melanocytes but cannot synthesize tyrosinase therefore melanin missing from hair, eyes, and skin |
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What is Vitiligo?
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partial or complete loss of melanocytes, leads to white spots
autoimmune, genetic, and environmental factors common in people with thyroid conditions melanocyte loss may be related to malfunction of immune system prominent in face, hands, and wrists depigmentation around orifices: mouth, eyes, nostrils, genitalia, and umbilicus |
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What is Jaundice?
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also known as Icternus
yellowish discoloration of skin, mucous membranes, and conjunctiva of eyes not a disease but can signify some pathology is present yellow pigment bilirubin builds up in ECF scratching is a common sign of Jaundice |
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What are the 3 types of Jaundice and examples?
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Pre-hepatic:
-hemolysis (leading to large amounts of bilirubin in the blood), malaria, sickle-cell anemia, and thalassemia Hepatic -hepatitis and liver cirrhosis Post-hepatic -bile stones (bilirubin blocked from going into digestive system) and pancreatitis |
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What is Erythema?
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redness of the skin
caused by engorgement of capillaries in dermis with blood associated with erythema marginatum, migrans, multiforme, nodosum, toxicum etc |
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What is the Subcutaneous layer?
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also called SubQ or Hypodermis
not part of skin but attaches skin to underlying tissues and organs contains lamellated (pacinian) corpuscles - detect external pressure applied to skin |
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What are the accessory structures of skin?
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hair, skin glands, nails
hair (pilli) functions: -proection -reduction of heat loss -sensing light touch (through hair plexuses) Nails - protect body sweat glands - regulated body temp |
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What is Hair?
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dead, keratinized epidermal cells
consists of: shaft - above surface of skin root - penetrates into dermis and sometimes subQ layer both layers consist of concentric layers: -medulla, cortex, and cuticle |
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What is the hair follicle?
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surrounds root and has:
external - continuation of epidermis internal - produced by hair matrix and forms cellular tubular sheeth between external root and hair both together make up epithelial root sheath dermal root sheath - dense dermis surrounding hair follicle bulb -base of hair follicle -onion shaped -has nipple shaped papilla which contains blood vessels -has germinal layer called matrix (from stratum basale) depilatory - substance that removes hair but doesn't affect root allowing re-growth |
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What are the sebaeous (oil) glands and arrector pili?
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sebaceous (oil) glands - smooth muscle cells associated with hairs
arrector pili - smooth muscle that extends from superficial dermis to dermal root sheath around side of hair follicle arrector pili stimulated autonomically during physiological (cold) and emotional (fright) stress reason for goosebumps |
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What are the stages of hair growth?
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growth (anagen) - hair grows longer
regression (catagen) - hair follicle atrophies and stops growing resting (telogen) - old hair falls out and new cycle begins growth stage - 2 to 6 years regression stage - 2 to 3 weeks resting stage - 3 months 85 % in growth stage |
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What are the types of hair?
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Lanugo - fine, nonpigmented, downy hair covering whole body during fetal life
terminal hairs - at birth, long, coarse, heavily pigmented hairs of eyebrows, eyelashes, and scalp Vallus hairs - same as terminal but places other than listed in terminal hair color - determined by amount and type of melanin in keratinized cells (produced by melanocytes) dark hair = eumelanin blond and red hair = pheomelanin white hair = decrease of melanin |
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What are characteristics of hair loss?
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normal = 70-100 hairs a day
caused by illness, radiation, chemo, age, genetics, gender, emotional stress, lack of nutrition (weight loss diets), increase in hair loss up to 3-4 months after child birth alopecia - partial or complete loss of hair caused by genetics, aging, endocrine disorders, chemotherapy or skin disease chemotherapeutic agents - interrupt life of rapidly diving hair matrix cells |
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Whats the role of hormones and hair?
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puberty males gain more hair due to androgens
puberty females androgens increase hair in axillae and pubic regions hirsutism - excessive amount of androgen, especially in pre-pubertal age androgenic alopecia - androgens inhibit hair growth (male pattern baldness) minoxidil - first drug for enhancing scalp hair growth |
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What are the major skin glands?
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epithelial cells which are examples of exocrine glands
sebaceous -simple, branched acinar glands -secrete oily substance called sebum (TG, cholesterol, Protein, and inorganic salts) which prevents dryness and brittleness and is antibacterial and moisturizing, cause acne during puberty -in superficial dermis -present in breasts, face, neck, and superior chest (large glands) -trunks and limbs (small glands) -NOT IN PALMS AND SOLES -open directly in lips, glans penis, labia minora, eyelids Suderiferous: -simple, coiled tubular glands -secrete sweat through pores -two types: Eccrine and Apocrine -sweat contains water, NaCl, ammonia, urea, uric acid, AA, lactic acid, glucose -hypotonic (more fluid than salts) -thermoregulator Ceruminous: -modified sweat glands in external ear -produce cerumen (ear wax) -secretory portion is in SubQ layer deep to sebaceous glands, excretes directly onto surface of ear canal or into ducts of sebaceous glands -form stick barrier that prevents entry of foreign organisms |
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What are Eccrine and Apocrine glands?
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Eccrine (merocrine):
-starts after birth -thermoregulatory -all over but most common in forehead, palms, soles -NOT in lips, nail beds of fingers and toes, glans penis, glans clitoris, labia minora, and eardrums -secretory portion is deep dermis -excretory duct opens at surface of epidermis as pore -sweat first appears on forehead and scalp, last in palms and soles -insensible (no moisture), sensible (moisture), and emotional (cold sweat in palms, soles, and axillae) Apocrine: -axilla, groin, areola of breasts, bearded regions of face -secretion via exocytosis (like merocrine) instead of being pinched (like apocrine) -secretory = SubQ layer -excretory = hair follicles -viscous and milky (lipids and proteins) -odorless but when bacteria present there is musky odor -starts at puberty -active in emotional and sex but NOT thermoregulatory |
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What happens when Cerumen is impacted?
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accumulation in the external auditory canal
accumulation causes impaction (firmly wedge) prevents sound from reaching eardrums need wax dissolving enzymes cotton-shwabs not recommended |
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What are the parts of a Nail?
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plates of tightly packed hard dead keratinized epidermal cells
body - vision portion (like stratum corneum) lunula - white crescent shaped at proximal end free edge - projects out from body hyponychium (nail bed) - below thickened stratum corneum, secures nail to fingertip root - goes into groove of skin eponychium - narrow band of epidermis that adheres to lateral border of nail wall matrix - proxial part of epithelium deep to root (germinative layer) |
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How do nails grow and what is their function?
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transformation of superficial cells of matrix into nail cells
1 mm/week help to grasp small objects, protect against trauma and allow for scratching |
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What do Epidermis and Dermis derive from?
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epidermis = ectoderm
-nails, hair, skin glands vernix caseosa - fatty substance that protects epidermis of fetus dermis = mesoderm |
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What is a First Degree Burn?
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only epidermis
mild pain, erythema, edema BUT NO BLISTERS heals within 3-6 days ex. mild sunburns, flames, flash from explosion |
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What is a Second Degree Burn?
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epidermis and papillary layer of dermis
some skin function lost redness, edema, BLISTERS 3-4 weeks healed w/o grafting ex. flames, flash, scald, contact burns |
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What is a Third Degree Burn?
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epidermis, dermis and SubQ Layer
most skin functions lost thrombosed vessels, no elasticity marble white, mahogany, or charred dry wounds edema with SENSORY LOSS slow regeneration, requires skin graft ex. flame, electricity, prolonged exposure, chemicals |
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What is a Fourth Degree Burn?
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up to muscles, fascia, or bone
all function lost black charred may require amputation, escharotomy, or fasciotomy escharotomy - surgical incision into necrotic tissue, prevents ischemia fasciotomy - cuts fascia to relieve tension or pressure ex. chemicals, high voltage shock, prolonged exposure to flame |
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What are the classifications of depth of burns?
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Superficial - epidermis only
Partial Thickness: -1st or 2nd degree superficial partial - papillary deep partial - reticular Full Thickness: -3rd or 4th degree TBSA: -Total Body Surface Area -major is 3rd degree over 10 % or 2nd degree over 25 % -also 3rd degree of face, hands, feet, or perineum |
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What is the Rule of Nines?
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9 % anterior + 9 % posterior of head and neck or upper limbs
4 times 9 % ant and post of trunk including butt 9 % of ant and post of lower excluding butt 1 % perineum when more than 70 %, 1/2 victims die |
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What are some complications of burns?
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shock
bacterial infection reduced circulation kidney damage decreased immunity electrolyte imbalance |
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What are the Early Warning Signs of MM?
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Asymmetry - lacks symmetry
Border - irregular borders like notched, indented, scalloped or indistinct Color - uneven coloration Diameter - moles more than 6 mm Elevation - mole above surface |
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What are the differences between thick and thin skin?
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Thick:
-areas such as palms, palmar surface of digits, and soles -thick strata lucidum, spinosum, and corneum -Epidermal ridges well developed and more numerous dermal papillae -NO hair follicles or Arrector pili mm -NO sebaceous glands -DENSE sensory receptors -MANY suderiferous glands Thin: -all parts of body EXCEPT palms, digits, and soles -NO Stratum Lucidum, thin spinosum and corneum -Lacking Epidermal ridges due to less developed dermal papillae -HAS Hair follicles and Arrector Pili mm -HAS sebaceous glands -LESS suderiferous glands -LESS sensory receptors |
