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80 Cards in this Set
- Front
- Back
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intercellular junctions
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all cells (except blood) anchored to each other or their matrix by intercellular junctions
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tight junctions
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-encircle the cell joining it to surrounding cells
-forming zipperlike complementary grooves & ridges -prevents passage b/w cells: GI & urinary tracts |
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desmosomes
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-patch b/w cells holding them together: cells spanned by filaments terminating on protein plaque
-cytoplasmic intermediate filaments also attach to plaque -uterus, heart, epidermis -found in intercalated discs |
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gap junctions
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-ring of transmembrane proteins from a water filled channel
-small solutes pass directly from cell to cell -in embryos, cardiac & smooth muscle -found in intercalated discs |
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cutaneous membrane
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-skin
-stratified squamous epithelium over connective tissue -relatively dry layer serves protective function |
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synovial membrane
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-lines joint cavities
-connective tissue layer only, secretes synovial fluid |
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serous membrane (serosa)
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-internal membrane
-simple squamous epithelium over areolar tissue, produces serous fluid -covers organs & lines walls of body cavities -pleura, peritoneum, pericardium |
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mucous membrane (mucosa)
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-epithelium, areolar (lamina propia), smooth muscle (muscularis mucosae)
-absorptive, secretory, protective -goblet cells |
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epidermis
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keratinized stratified squamous epithelium
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dermis
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connective tissue layer
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hypodermis
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below the dermis
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thickness variable
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1-2mm
-dermis may thicken up to 6mm -stratum corneum layer increased -calluses on hands & feet |
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functions of the skin
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-resistance to trauma & infection
-packed with keratin & linked by desmosomes -acid mantle (pH 4-6) -barrier to UV light & water -vitamin D synthesis -sensory receptors -thermoregulation -social functions (good & bad) |
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cells of the epidermis: stem cells
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undifferentiated cells in deepest layer
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cells of epidermis: keratinocytes
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most of the skin cells
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cells of epidermis: melanocytes
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synthesize pigment that shield UV
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cells of epidermis: tactile (Merkel) cells
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receptor cells associated with nerve fibers
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cells of epidermis: dendritic (Langerhans) cells
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macrophages guard against pathogens
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layers of epidermis: bottom to top
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stratum basale
stratum spinosum stratum granulosum stratum lucidum (only in thick skin) stratum corneum |
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stratum basale
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-single layer cells on basement membrane
-cell types in this layer -keratinocytes: undergo mitosis to replace epidermis -melanocytes: distribute melanin through cell processes; melanin picked up by keratinocytes -merkel cells are touch receptors that form merkel disc |
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cells of epidermis: melanocytes
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synthesize pigment that shield UV
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cells of epidermis: tactile (Merkel) cells
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receptor cells associated with nerve fibers
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cells of epidermis: dendritic (Langerhans) cells
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macrophages guard against pathogens
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layers of epidermis: bottom to top
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stratum basale
stratum spinosum stratum granulosum stratum lucidum (only in thick skin) stratum corneum |
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stratum basale
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-single layer cells on basement membrane
-cell types in this layer -keratinocytes: undergo mitosis to replace epidermis -melanocytes: distribute melanin through cell processes; melanin picked up by keratinocytes -merkel cells are touch receptors that form merkel disc |
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stratum spinosum
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-several layers of keratinocytes
-appear shiny due to shrinkage during histological preparation -contains dendritic (Langerhans) cells -macrophages from bone marrow that migrate to the epidermis -800 cells/millimeter2 -help protect body against pathogens by "presenting" them to the immune system |
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stratum granulosum
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-3 to 5 layers flat keratinocytes
-contain keratinohyalin granules -combine with filaments of cytoskeleton to form keratin -produces lipid filled vescicles that release a glycolipid by exocytosis to waterproof the skin -forms barrier b/w surface cells & deeper layers of the epidermis -cuts off surface strata from nutrient supply |
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stratum lucidum
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-thin translucent zone seen only in thick skin
-keratinocytes are packed with eleidin, a precursor to keratin; does not stain well -cells have no nucleus or organelles |
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stratum corneum
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-up to 30 layers of dead scaly keratinized cells
-surface cells flake off (exfoliate) |
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life history of keratinocytes
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-produced by stem cells in stratum basale
-new cells push others towards surface -cells grow flat & fill with vesicles |
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water barrier
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-b/w granulosum & spinosum
-lipids -tight junctions -protein coat of inner lining of keratinocyte cell membrane -prevents dehydration |
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dermis
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-thickness=0.6mm to 3mm
-composition: collagen, elastic, & reticular fibers, fibroblasts -dermal papillae: extensions of the dermis into the epidermis; forming the ridges of the fingerprints |
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dermal layer
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-papillary layer:thin zone of areolar CT
-immune cells to guard against breaks -small blood vessels -reticular layer is deeper part of dermis: dense irregular CT |
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hypodermis
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-subcutaneous tissue/superficial fascia
-mostly adipose -functions: energy reservoir and thermal insulation -hypodermic injections (subQ): highly vascular |
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skin colors (pigmentation)
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-hemoglobin=red pigment of RBS's
-carotene=yellow pigment: concentrates in stratum corneum & fat -melanin=yellow, brown, & black hues: pigment synthesis stimulated by UV radiation |
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abnormal skin colors
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-cyanosis=blueness from deficiency of oxygen in the circulating blood (cold weather)
-erythema=redness due to dilated cutaneous vessels (anger, sunburn, embarrasment) -jaundice=yellowing of skin & sclera due to excess of bilirubin in blood (liver disease) (seen in babies but not threatening) |
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abnormal skin colors
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-bronzing=golden brown color of Addison disease (deficiency of glucocorticoid hormone)
-Pallor=pale color from lack of blood flow -albinism=a genetic lack of melanin -Hematoma=a bruise (visible clotted blood) |
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hemangiomas (birthmarks)
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discolored skin caused by benign tumors of dermal blood capillaries (strawberry birthmarks disappear in childhood--port wine birthmarks last for life)
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freckles & moles
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aggregations of melanocytes
-freckles are flat; moles are elevated |
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friction ridges
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leave only fingerprints on touched surfaces:unique pattern formed during fetal development
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flexion creases
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form after birth by repeated closing of the hand
-lines form in wrist & elbow areas |
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char. of human hair
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-hair is composed of hard keratin
-found almost everywhere:different b/w sexes or individuals is difference in texture & color of hair |
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3 diff. body hair types
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-lanugo: fine, unpigmented fetal hair
-vellus: fine, unpigmented hair of children & women -terminal hair: course, long, pigmented hair of scalp |
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structure of hair & follicle
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-hair is filament of keratinized cells: shaft above skin, root w/in follicle (in cross section: medulla, cortex, cuticle)
-follicle is oblique tube w/in the skin -bulb is where hair originates -vascular tissue (papilla) in bulb provides nutrients -texture & shape of hair: straight hair=round, wavy=oval |
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structure of hair follicle
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-epithelial root sheath
-connective tissue root sheath -hair receptors entwine each follicle -piloerector muscle:goose bumps |
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drug detection in hair
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-can detect many drugs (amphetamines, barbituates, cocaine, etc) used w/in 3 months
-heavy metal poisoning (arsenic, thallium, lead) |
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hair growth & loss
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-hair cycle=3 repeating cycles
-anagen is growth stage (90% of scalp follicles) & lasts 6-8 years in young adult -catagen is shrinking follicle & lasts 2-3 weeks -telogen is resting stage & lasts 1-3 months -thinning or baldness=alopecia -pattern baldness=genetic & hormonal -sex influenced trait (dominant in males, recessive in females); expressed only with high testosterone levels -hirsutism=excessive hair growth -hormone imbalance (ovary or adrenal cortex problem) |
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functions of hair
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-body hair (too thin to provide warmth: alert us to parasites crawling on skin
-scalp hair: heat retention & sunburn cover -beard, pubic, & axillary hair: indicate sexual maturity & help distribute sexual scents -guard hairs & eyelashes: prevent foreign objects from getting into nostrils, ear canals, or eyes -expression of emotions w/ eyebrows |
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nails
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-derivative of stratum corneum; densely packed cells filled with hard keratin
-flat nails allow for fleshy, sensitive fingertips -growth rate is 1mm per week -new cells added by mitosis in the nail matrix -nail plate is visible part of nail |
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sweat glands
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-filtrate of plasma & some wast products
-99% water, ions, urea, & other wastes (some NaCl, may have fatty acids) -pH 4-6, acid mantle -500 mL of insensible perspiration/day -sweating with visible wetness is diaphoresis |
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sweat glands
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-merocrine glands is simple tubular gland
-apocrine glands produce sweat containing fatty acids -cells in both glands secrete by exocytosis |
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sweat glands
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-filtrate of plasma & some other waste products
-99% water, ions, urea, & other wastes, some NaCl, may have fatty acids -pH4-6 |
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merocrine glands
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-simple tubular gland
-millions of them help cool the body -myoepithelial cells contract to sqeeze perspiration out duct -cells secrete by exocytosis |
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apocrine glands
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-produce sweat containing fatty acids
-found only near hair follicles & respond to stress & sex -bromhidrosis is body odor produced by bacterial action on fatty acids -cells secrete by exocytosis |
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sebaceous glands
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-oily secretion called sebum that contains broken down cells (lanolin in skin cream is sheep sebum)
-flask shaped gland with duct that opens into hair follicle |
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ceruminous glands
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-found only in external ear canal
-their secretion combines with sebum to produce earwax (waterproof keeps eardrum flexible & its bitterness repel mites & other pests |
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mammary glands
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-breasts of both sexes rarely contain glands, modified apocrine gland
-secondary sexual char. of females found only during lactation & pregnancy |
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skin cancer
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-induced by UV rays of the sun
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basal cell carcinoma
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-least dangerous
-arises from stratum basale & invades dermis |
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squamous cell carcinoma
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-arises from keratinocytes in stratum spinosum
-metastasis to the lymph nodes can be lethal |
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malignant melanoma
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-most deadly
-arises from melanocytes of a preexisting mole -ABCD: asymmetry, border irregular, color mixed & diameter over 6mm -result of oncogene BRAF in men |
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`burns
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-hot water, sunlight, radiation, electric shock or acids & bases
-death from fluid loss & infection |
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1st degree burn
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only epidermis (red, painful, & edema)
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2nd degree burn
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-epidermis & part of dermis (blistered)
-epidermis regenerates from hair follicles & sweat glands |
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3rd degree burn
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-epidermis, dermis & more is destroyed
-often requires grafts or fibrosis & disfigurement may occur |
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burn treatment
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IV nutrition & fluid replacement, debridement & infection control
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skin grafts & artificial skin
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-3rd degree burns require skin grafts
-graft options -autograft: tissue from patient -isograft: tissue from identical twin -cultured keratinocyte patches -temporary grafts (immune system) -homograft (allograft): from unrelated person -heterograft |
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skeletal system functions
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-bones, cartilage, ligaments
-support -protection -movement -electrolyte balance -acid/base balance -blood formation |
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bone as a tissue
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-connective tissue with a matrix hardened by minerals (calcium phosphate)
-individual bones consist of bone tissue, marrow, blood, nerves, adipose, cartilage, & periosteum -continually remodels itself |
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long bones
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levers acted upon by muscles
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short bones
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glide across one another in multiple directions
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flat bones
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protect soft organs
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irregular bones
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protection & muscle attachment
-ex: vertebral column & pelvic girdle |
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shaft (diaphysis) of bone
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cylinder of compact bone
-marrow cavity (osteogenic cells & reticular connective tissue) |
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enlarged ends (epiphyses) of bone
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-spongy bone covered by compact bone
-enlarged to strengthen joint & attach ligaments |
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structure of a long bone
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-compact & spongy bone
-marrow cavity -articular cartilage -periosteum |
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features of bones
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-joint surface covered with articular cartilage
-shaft covered with periosteum -outer fibrous layer of collagen -inner osteogenic layer of bone forming cells -epiphyseal plate (growth plate) |
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compact bone
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made up of osteons (made of lamellae)
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spongy bone
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-trabeculae
-lamellae but no osteons |
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structure of a flat bone
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-external & internal surfaces composed of compact bone
-middle layer is spongy bone & bone marrow -skull fracture may leave inner layer of compact vone unharmed |
