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101 Cards in this Set
- Front
- Back
What are the two main classifications of CT?
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Embryonic and adult
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List the two types of embryonic CT
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Mesenchyme and mucous
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List the 5 types of adult CT
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1) Loose
2) Dense (irregular and regular) 3) Reticular 4) Adipose 5) Specialized (cartilage, bone, and blood) |
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Describe mucous CT
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1) Contains an abundance of ground substance with collagen and a few elastic and reticular fibers
2) Cells are ovoid or stellate shaped with thin cytoplasmic processes (consider them stem cells) similar to mesenchymal or fibrocytes in appearance 3) Umbilical cord matrix cells are stem (pleuripotential) and can develop into blood cells and other tissue 4) Present in umbilical cord and young tooth pulp |
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Describe mesenchyme CT
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1) Contains abundance of mesenchymal cells that are pleuripotent with a few fibers
2) Fxn- transient CT which forms adult CT |
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List and describe two types of cells in CT proper
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1) Fixed- production and maintenance, reserve fuel
2) Wandering- from blood |
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Define fibroblast
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Former fibrocyte
Inactive |
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Define myofibroblast
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Stronger contractile properties
Adds alpha-smooth muscle actin Differentiates from fibroblast and other cells |
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What are pericytes?
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Undifferentiated mesenchymal cells
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What are some examples of wandering cells?
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1) Neutrophil
2) Lymphocyte 3) Eosinophil 4) Basophil |
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What are 3 fibers of CT proper?
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1) Collagen
2) Elastic 3) Reticular |
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Describe collagen fibers
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Produced by many cell types but predominately fibroblasts
Unique chemical composition Wavy acidophilic bundles of collagen visible with LM Collagen fibril --> collagen fibers --> collagen bundles Periodicity Biosynthesis and arrangement into fibers |
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What is the definition of CT?
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Tissue composed of 3 components: cells, fibers, and ground substance
Fibers and g.s. have become known as ECM Contains abundant intercellular material or matrix |
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What is the fxn of CT?
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1) Support (structure and packing, ex tendons, ligaments, and aponeurosis, organ capsules, adipose)
2) Defense ( site of immune rxns, phagocytosis, physical barrier, limits spread of infection) 3) CO2 and O2 exchange 4) Repair (wounds or wound healing) |
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What is the structure of the fibroblast?
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Stellate-shaped or spindle
Ovoid, large pale-staining nucleus Basophilic cytoplasm |
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What is the fxn of fibroblast?
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Intense synthetic activity
Ex wound healing |
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What is the structure of myofibroblast?
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Similar to fibroblasts but add microfilaments
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What is the fxn of myofibroblast?
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Wound contraction
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What is the structure of a macrophage?
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Large cells
Cytoplasmic debris Heterogenous cytoplasm Sometimes foamy Irregular nucleus |
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What is the fxn of a macrophage?
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Ingestion and digestion
Cell mediated resistance to bacteria, viruses, protozoa, fungi and tumors Destruction of RBCs Ag presenters |
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What is the structure of a plasma cell?
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Ovoid shape but can vary
Spherical, eccentric nucleus Juxtanuclear golgi Basophilic cytoplasm Clockface nucleus |
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What is the fxn of a plasma cell?
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Synthesis of Abs of Igs
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What is the structure of a mast cell?
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Large, oval cells
Homogenous cytoplasm Centrally-located, oval nucleus Located near blood vessels Scroll or whorl patterned granules |
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What is the fxn of a mast cell?
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Store and release chemical mediators of inflammation and hypersensitivity
Promotes allergic rxns known as immediate hypersensitivity rxns Contents of granules cause contraction of smooth muscle and dilation of capillaries |
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What is the structure of fat cells?
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Contain one central droplet of fat in cytoplasm
Formed from small droplets fusing Nucleus flattened Typical mitochondria, rER, sER around nucleus Each cell surrounded by basal lamina Lipid dissolved in preparation Every cell in contact with capillaries Thin cytoplasm with microfilaments |
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What is the fxn of fat cells?
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Energy source
Cushion Leptin production |
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List the principal tissue of distribution and cells of origin of type I collagen
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1) Loose and dense ordinary CT; tendon, ligaments, fascia. Cells of origin- fibroblasts and reticular cells; smooth muscle cells
2) Fibrocartilage. CO- chrondrocytes 3) Bone. CO- osteoblasts 4) Dentin. CO- odontoblasts |
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List the principal tissue of distribution and cells of origin of type II collagen
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1) Hyaline and elastic cartilage. CO- chondrocytes
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List the principal tissue of distribution and cells of origin of type III collagen
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1) Loose CT; fiber collagen. CO- fibroblasts and reticular cell
2) Papillary layer of dermis. CO- fibroblasts 3) Blood vessels. CO- smooth muscle cells; endothelial cells |
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List the principal tissue of distribution and cells of origin of type IV collagen
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1) Basal lamina, external lamina. CO- epithelial and endothelial cells
2) Lens capsule of eye. CO- lens fibers |
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List the principal tissue distribution and cells of origin of type V collagen
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1) CT stroma. CO- fibroblasts, reticular cells, smooth muscle cells
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List the principal tissue distribution and cells of origin of type VII collagen
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1) Anchoring fibrils, securing BL to CT fibers. CO- fibroblasts
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List the principal tissue distribution and cells of origin of type X collagen
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1) Zone of hypertrophy. CO- chondrocytes
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What produces reticular fiber?
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Fibroblasts, reticular cells and others
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Describe the size and appearance of reticular fibers
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Smaller than collagen, thin, form a network, stretch more than collagen
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What are the composition and staining characteristics of reticular fibers?
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High content of glycoproteins so stain well with PAS, weak with H&E
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What are the common sites of reticular fibers
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Expandible organs, hematopoietic organs (spleen, lymph nodes, bone marrow), liver, blood vessels
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What are the two main producers of elastic fibers?
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Fibroblasts and smooth muscle cells
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Describe the size and appearance of elastic fibers
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Thin, long, united, and branched
Yellow grossly |
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Describe the composition and staining characteristics of elastic fibers
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Protein elastin and microfibrils, interlinked molecules, weak H&E, desmosine and isodesmosine
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What are the common sites of elastic fibers?
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Ligamentum nuchae, vocal cords, aorta, lung and special arrangement in vessels
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What is the definition of ground substance?
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Amorphous, colorless, transparent, homogenous material that fills space between cells and fibers
Appears as an empty background with H&E |
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What are the two groups of composition of the ground substance?
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1) Glycosaminoglycans
2) Glycoproteins |
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Glycosaminoglycans combine with proteins to form proteoglycans. What are the two types of GAGs?
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Sulfated (provide support, H2O binding) and nonsulfated
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What are the three types of glycoproteins?
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1) Fibronectin
2) Laminin 3) Interaction with integrin |
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Describe loose (areolar) CT
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Cellular, flexible, delicate, well vascularized
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What are the fxns of loose CT?
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1) Antigen and bacteria interaction
2) Inflammatory rxns |
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What are the locations of loose CT?
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Dermis and submucosa
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Describe dense irregular CT
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Preponderance of collagen fibers
Fibers are arranged in no definite pattern |
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What is the fxn of dense irregular CT?
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Strength
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What is the location of dense irregular CT?
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Dermis and submucosa
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Describe dense regular CT
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Collagen fibers in definite orientation
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What is the fxn of dense regular CT?
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Strength
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What is the location of dense regular CT?
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Tendons, aponeurosis, and ligaments
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What is the fxn of reticular CT?
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Provides a framework, support, expandible
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What is the location of reticular CT?
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Expandible organs (lymph nodes, bone marrow, spleen)
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What is the fxn of adipose tissue?
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Support, energy, and insulation
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Describe brown fat
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Lots of cytrochrome oxidase in mitochondria
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What is the location of adipose tissue?
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Hypodermis, around organs, orbits, beneath visceral pericardium
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What cell produces leptin?
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Adipocytes
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What hormones are secreted by adipocytes?
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1) Angiotensinogen (AGE)
2) Adiponectin 3) Resistin (all 3 hormones) 4) Steroid hormones |
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What is the significance of pericytes?
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Can develop into endothelial cell, adipose cell, smooth muscle cell, or skeletal muscle cell
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What cells are derived from mesenchymal cell?
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Mesothelial, endothelial, osteoblasts, chrondoblasts, adipocytes, and fibroblasts
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List the steps of collagen formation in a typical fibroblast?
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1) Formation of mRNA in nucleus
2) Initiation of synthesis of pro-alpha chains with signal sequences by ribosomes 3) Synthesis of pro-alpha chains on rER 4) Hydroxylation of proline and lysine residues (require Vitamin C) and cleavage of signal sequence from pro-alpha chains 5) Glycosylation of specific hydroxylysyl residues in the rER 6) Formation of procollagen triple helix molecules from a C terminus toward the N terminus in a zipper-like manner 7) Stabilization of the triple helix by formation of an intra- and interchain hydrogen and disulfide bonds and chaperone proteins 8) Transport of procollagen molecules to G.A. 9) Packaging of procollagen molecules by G.A into secretory vesicles 10) Movement of vesicles to plasma membrane, assisted by molecular motor proteins associated with microtubules 11) Exocytosis of procollagen molecules 12) Cleavage of trimeric globular C- and helical N-procollagen domains by procollagen N- and C-proteinases 13) Polymerization (self-assembly) of collagen molecules into collagen fibrils (in a core of fibroblast) in development of covalent cross-linking 14) Incorporation of other collagens (type V, FACTTs, etc.) into collagen fibrils |
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Identify the unique structural characteristics and biochemical properties of collagen
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1) Relatively inelastic, high tensile strength, transparent (cornea)
2) Wavy, acidophilic bundles 3) Procollagen-->fibril-->fiber-->bundles 4) Fxn in 4 sites: tendon (ropes), cornea (transparent sheet), bone (scaffold for mineral), and joints (weight bearing) 5) Bands repeat every 68 nm 6) Single collagen molecule consists of 3 polypeptides known as alpha-chains 7) Made of glycine, hydroxyproline or hydroxylisine, and proline 8) Collagen=glycoprotein 9) Several classes based on polymerization pattern 10) Collagen formation 11) Collagen synthesis by fibroblasts and epithelial cells 12) Collagen degradation by proteinases 13) Can be degraded via proteolytic or phagocytic degradation |
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What are the 3 components of the ground substance?
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1) Proteoglycans
2) Multiadhesive glycoproteins 3) GAGs |
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What is mucous CT derived from?
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Mesoderm
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What 6 cells come from mesenchyme?
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1) Mesothelial
2) Endothelial 3) Osteoblasts 4) Chondroblasts 5) Adipocytes 6) Fibroblasts |
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What is a keloid and what is it caused by?
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Scar tissue caused by overproliferation
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Describe Dupuytrens' disease
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Involves myofibroblasts of palma fascia
Palmer aponeurosis contracture |
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What are histiocytes called when found in other locations?
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Liver- Kupfer cells
Lung- Alveolar macrophage CNS- microglial cells Lymph node, spleen Epidermis- Langerhahn cells |
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Why are plasma cells found near the epithelium?
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To process antigens
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What are plasma cells derived from?
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Mesoderm, directly from B lymphocyte
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Describe the mast cell response
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1) 1-5 seconds: degranulation of primary mediators and lipid mediators of inflammation are triggered
2) 5-30 minutes: PGE2 (prostaglandin) is a vasodilator; Leukotriene C4 (LTC4) induces vasoconstriction and also causes bronchoconstriction 3) Hours- TNF, interleukin, PAF stimulate protein synthesis |
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What is the role of histamine?
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Contracts visceral arterial (vasoconstriction) and bronchial smooth muscle (bronchoconstriction) and relaxes peripheral arterial smooth muscle (vasodilation) and contracts endothelial cell
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Pericyte has the potential to develop into what?
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Endothelial cell, adipose cell, or smooth muscle
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What produces collagen?
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1) Smooth muscle cells
2) Schwann cells 3) Osteoblasts |
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What are two characteristic amino acids of collagen?
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Hydroxyproline and hydroxylisine
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What is another name for osteogenesis imperfecta?
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Brittle bone disease
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What type of stain do reticular fibers stain well with?
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PAS and silver
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What is the role of matrix metalloproteinases?
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Zinc dependent enzyme that degrade all components of ECM
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What is the role of tissue inhibitors of metalloproteinases (TIMPs)?
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Hold MMPs as inactive
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What are 4 MMPs?
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1) Collagenase
2) Stromelysins 3) Elastases 4) Gelatinases |
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What is hyaluronen?
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A GAG, excellent lubricant and shock absorber
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What is dermatan sulfate?
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A GAG, skin, blood vessels, heart; inplicated in CV disease, wound repair
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What is heparan sulfate?
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A GAG, BL and normal component of cell surface, allows interaction with FGF
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What is syndecan?
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A GAG core protein
Transmembrane protein that can link to BL thru heparan sulfate |
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What is the role of fibronectin?
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Fxn in cell adhesion and migration
Binds to integrin |
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What are the binding sites of fibronectin?
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1) Collagens I, II, III, and IV
2) Heparan sulfate 3) Fibrin 4) Hyaluronan 5) Fibronectin 6) Integrin |
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Osteopontin binds to osteoclasts, and possesses binding sites for what?
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Calcium and hydroxyapetite
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What is leptins role?
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Regulates amount of adipose tissue in the body and in food ingestion
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Where are receptors for leptin found?
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Hypothalamus
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What type of collagen is defective in osteogenesis imperfecta?
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Type I
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What is effected in Marfan syndrome?
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Fibrillin
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What type of collagen is defective in Ehrlos-Danlos?
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Type III
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Describe Alport syndrome
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Collagen IV defects
Causes basement membrane disorder Hematuria is most common and earliest manifestation |
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Describe lipoma
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Most common benign tumor in men
Derived from subcutaneous adipose tissue |
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Describe multiple myoma
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Plasma cell dyscrasia (abnormal condition of blood)
Sheet or aggregates of malignant plasma cells are present in bone marrow Monoclonal spike with electrophoresis (M component) Degrades corticol bone |
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Describe anaphylaxis
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Life threatening hypersensitivity rxn, bronchoconstriction occurs
Hives due to skin edema Result of mast cell degranulation |
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Describe malignant fibrous histiocytoma
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Most common type of soft tissue tumor
Variety of cells present, including fibroblasts, myofibroblasts, macrophages, and mesenchymal cells Arises in deep fascia, soft tissues of neck and extremities, and skeletal muscle |
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Describe Hurler syndrome
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Increase in dermatan sulfate and heparan sulfate, and LSD
Can affect several organs and overall body growth leading to dwarfism and unique facial features |