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35 Cards in this Set
- Front
- Back
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histology
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microscopic study of tissue
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tissue
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a group of cells that usually have a common embryological origin and function together to carry out a specific function. Communication between these cells allows them to function as a unit. Classified into 4 groups based on structure of cells, composition of noncellular, extracellular matrix, and cell function.
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epithelial tissue
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covers surfaces, lines inside of organs and body cavities, and forms glands. has 2 general classifications: covering and lining, and glandular. CHARACTERISTICS: cells are arranged close together in a single layer or multiple layers. many gap junctions. avascular tissue(NO blood vessels). cells rely on diffusion of O2 and nutrients from nearby tissues. has nerve supply. high rate of mitosis. FUNCTIONS: protecting underlying structures. acting as barriers. permitting the passage of substances. secreting and absorbing substances.
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connective tissue
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protects and supports body, binds organs together, provides immunity. most abundant tissue in the body, found in every organ. CHARACTERISTICS: cells scattered, with matrix (substance in between cells). not located on surface. most has a nerve supply (except cartilage). highly vascularized (except cartilage and tendons). matrix may be solid, fluid, semifluid. FUNCTIONS: enclosing and seperating, connecting tissues, supporting and moving, storing, cushioning and insulating, transporting, protection.
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muscle tissue
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movement, maintaining posture, and thermogenesis (generation of heat). 3 different types: skeletal, smooth and cardiac.
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nervous tissue
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complex. initiate and transmits impulses (action potentials) that control and coordinate the functioning of the body. has 2 types of cells: neuroglia cells and nerurons.
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covering and lining epithelium
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forms the outside layer of the skin and the outside and inside layer of internal organs and structures. cells can be simple or stratified. cell shapes can be squamous, cuboidal, or columnar. specialized cells can be pseudostratified or transitional.
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glandular epithelium
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makes up the secreting portion of the glands. exocrine and endocrine.
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gap junctions
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specialized contact regions; communication, coordination. form channels between adjacent cells.
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endocrine glands
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gland becomes seperated from epithelium from which it developed. secretions dont go through a duct. secretions are called hormones. ex. pituitary gland and adrenal gland.
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exocrine glands
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gland maintains an open contact with the epithelium from which it developed. the secretions that are produced flow through a tuble-like passageway (duct) to get to the surface or the lumen surface of the organ. ex: mucus, digestive glands. 3 types; merocrine, apocrine, holocrine
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merocrine
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secrete products with no loss of cellular material. (cytoplasm) secretion leaves by active transport or exocytosis.
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apocrine
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discharge fragments of the gland cells in the secretion. apex of cell pinches off. ex: milk producing mammary glands
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holocrine
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(whole) shred entire cells in the secretion. as secretion accumulates in cell, it ruptures and dies. ex: sebaceous (oil) glands
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connective tissue cells
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adipocytes, mast cells, white blood cells, macrophages (fixed and wandering), stem cells (undifferentiated mesenchyme)
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extra cellular matrix
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gives connective tissues most their functional characteristics. EX: bone and cartilage-- ability to bear weight. tendons and ligaments-- ability to withstand tension.3 major components: protein fibers (collagen, reticular, and elastic.) ground substance (hyaluronic acid, proteoglycans, and adhesive molecules), fluid.
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mesenchyme
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all adult connective tissue is derived from embryonic connective tissue called...
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types of connective tissue
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loose, dense, tissue with special properties (adipose, reticular), cartilage, bone, blood and hemopoietic tissue.
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membrane
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thin sheet of tissue that covers a structure or lines a cavity. most are composed of epithelium and the connective tissue under it.
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skin
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external membrane of the body
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mucous membrane
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an internal membrane. consists of epithelial cells, basement membrane, and lamina propria. lines cavities and canals that open to the outside. contain goblet cells or mucous glands that produce mucus. FUNCTION: protection, absorption, and secretion.
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lamina propria
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connective tissue found under the epithelium of mucous membranes
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serous membrane
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consist of mesothelium (simple squamous epithelium), basement membrane and loose connective tissue. lines cavities that do NOT open to the exterior of the body and cover the organs in those cavities. cells of the membrane produce serous fluid that decreases friction.
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synovial membranes
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consist of modified connective tissue cells that either: 1) mixed with the dense connective tissue of the joint capsule, or 2) are seperated from the joint capsule. Lines the capsule of freely movable joints (shoulder, thigh). Cells produce synovial which is rich in hyaluronic acid.
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inflammation
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occurs when tissues are damaged or as an immune response. Mobilizes the body's defenses, isolates and destroys microorganisms and other agents, removes foreign material and damaged cells so tissue can repair. MANIFESTATIONS: redness, heat, swelling, pain, function disturbance.
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tissue repair
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the substitution of viable cells for dead cells via regeneration or replacement
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regeneration
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new cells are the same type as those that were destroyed; normal function is restored.
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replacement
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a new type of tissue develops--- scar production and loss of some tissue function usually occurs
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labile cells
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cells continue to divide throughout life; damage repaired by regeneration.
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stable cells
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do not divide after growth ceases, but retain the ability to divide in response to injury (regeneration)
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permanent cells
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very limited ability to replicate; if killed usually replaced by a different cell type.
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primary union (primary intention or first intention)
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edges are close together. wound fills with blood, scab forms, inflammatory response, fibroblasts from surrounding connective tissue migrate into clot and produce collagen and other components, revascularization, fibrin broken down and removed. granulation tissue replaces clot.
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scar
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large amounts of granulation tissue composed of dense irregular collagenous connective tissue.
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secondary union (second intention)
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edges are far apart. clot may not close gap completely. takes longer for epithelial cells to regenerate and cover wound. inflammatory response is greater. more granulation tisse forms. wound contraction occurs.
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tissue and aging
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rate of healing and scarring are very different in elderly than young. cells divide more slowly, collagen fibers become more irregular in structure and may increase in number. elastic fibers become less elastic. arterial walls become less elastic and atherosclerosis is more prominent. reduced rate of RBC synthesis. reduced flexibility and elasticity of connective tissue. increased tendency to break bones.
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