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47 Cards in this Set
- Front
- Back
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Which embryonic layer is connective tissue derived from?
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The middle germ layer, mesoderm.
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Functions of CT?
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Holds tissues together and forms framework of organs, underlies epithelium, important in defense agains foreign bodies and repair of injuries, forms tendons and ligaments, FAT serves as energy storage and insulation.
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What are the three components of CT?
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Ground substance, fibers and cells.
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What are the characteristics of ground substance?
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Amorphous, colorless, homogeneous
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What are the three components of the composition ofground substance?
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Proteoglycans, Glycoproteins, Tissue fluid
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What are the three fiber types of CT?
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Collegen, Elastic, Reticular
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What color do collagen fibers stain in an H & E stain?
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Pink. Acidophillic.
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What is characteristic of elastic fibers?
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Composed of elastin, contains microfibrils composed by fibrillin, a proein. Stain very weakly (not at all) wih H &E. Sained with orcein or resorcin-fuchsin will stain purple, dark blue or blue-black. Found in walls of blood vessels.
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What tissue disorder is characterized by abnormal elastic tissue? What gene is defective?
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Marfans syndrome, an autosomal dominant disorder. Fibrillin gene is defective in this disorder.
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What are reticular fibers made of?
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Type III collagen
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What is the function of reticular fibers?
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Form the framework of organs such as lymph nodes and the sleen. Compose the reticular lamina, which underlies the basal lamina of epithelium.
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What do reticular fibers stain with?
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Silver salts. Called argyrophilic.
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How many types of collagen have been identified? Which 5 are most abundant?
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16 identified. Refer to book p 100?
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What are the most abundant cell type in CT? What do they do?
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Fibroblasts. They synthesize extracellular matrix (ground substance and fibers) Myofibroblasts are abundant at sites of wound healing.
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What are adipocytes?
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Specialized connective tissue cells for storing triglycerides. Are resident cells in CT. Have a basal laminae.
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What are the immigrant cells to CT?
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Macrophages, Mast cells, Plasma cells, leukocytes
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What is the purpose of white fat?
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Is unilocular (one large fat drop pushes nucleus and cytoplasm off to side). Energy storage, insulation, cushioning of vital organs, hormone secretion
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What is the purpose of brown fat?
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Multilocular. Large in newborns. Lipid mobilized and heat generated when stimulated by sympathetic nervous system.
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Is any brown fat found in adults? Where?
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Yes, not very common. Found in only a few places such as around the kidneys, adrenal glands, aorta, neck and mediastinum.
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What does ghrelin do?
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Is a short term regulator of appetite. It is a polypeptide from the gastric epithelium and acts through the hypothalamus to stimulate hunger.
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What disease is associated with the overproduction of ghrelin?
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Prader-Willi syndrome
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What does peptide YY do?
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Another short term appetite regulator. Is a gastrointestinal peptide that signals satiety through the hypothalamus.
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What is the function of insulin?
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Long term regulation of body weight. Stimulates lipid synthesis and blocks lipolysis.
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What is the function of leptin?
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Produced by fat cells and works on the hypothalamus to surpress appetite. Obese ppl are believed to be leptin resistant.
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What is a mast cell?
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Large, ovoid cell with numerous cytoplasmic granules. Hemopoietic origin (stem cell is in bone marrow) but differentiates in CT.
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What is a plasma cell dervied from?
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B-lymphocytes
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What is the function of a plasma cell?
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Produce antibodies to foreign substances. Has a large eccentric nucleus with a "clock face" appearance due to its chromatin.
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What are the for types of leukocytes?
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Neutrophils, eosinphils, basophils, lymphocytes
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What is a leukocyte?
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White blood cells. Derived from bone marrow, enters CT by diapedesis.
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What is a neurtrophil?
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A type of leukocyte. First to arrive at site of inflammation. The are phagocytic and specialized for killing and removing bacteria.
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What is an eosinphil?
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A type of leukocyte. eosinophillic (bright pink granules), bilobed nucleus. Increase during allergic response and parasitic infections. Phagocyize antigen-antibody complexes.
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What is a basophil?
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A type of leukocyte. Has granules similar to mast cells but are different because basophils contain histamine.
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What are lymphocytes?
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A type of leukocyte. Small cells with large dark nucleus surrounded by thin rim of basophilic cytoplasm. Mostly fond in CT underlying epithelium of the GI tract, also found in CT of resp system. Accumulations typically characterize chronic inflammation.
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What is characteristic of loose CT?
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has lots of cells compared to fibers. usually very vascular, typically lies immediately beneath epithelia. loose CT in this location sometimes referred to as lamina propina.
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Explain the difference between dense regular and dense irregular CT?
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Dense regular has abundant fibers (collagen) arranged in regular bundles and/or sheets. ex:tendons, ligaments, aponeuroses. Dense irregular has fibers arranged in a very irregular fashion;random bundles of collagen fibers. ex: dermis of skin.
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What is edema generally caused by?
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Venous obstructions which cause decreased venous flow, can cause an accumulation of fluid in the CT.
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What leads to protein deficiency and edema in third world countries?
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Due to starvation which results in decreased concentration of plasma proteins. the loss of ABUMIN can lead to edema.
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What causes scurvy and why is it a CT disease?
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Vitamin C deficiency. Vit C is important in the synthesis of collagen in the hydroxylation step.
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What is the composition of ground substance?
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Glycoaminoglycans (GAG's)- most abundant, neg charged so attract h2o and form hydrated gel, Proteoglycans- synthesized by resident cells of CT, have protein backbone with GAGs. Hydrophillic, surrounded by a thick layer of solvation water. Multiadhesive glycoproteins- laminin (component of basal lamina) and fibonectin.
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What type collagen forms classically described collagen fibers and can form collagen bundles?
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Type I
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What is the general name of more than 10 inherited disorders involving genetic defects in collagen and CT synthesis and structure?
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Ehlers-Danlos syndrome (EDS). Type IV (common) is characterized by a decreased amount of type III collagen. Types V and VI are characterized by deficiencies in hydroxylase and lysyl oxidase. Type VII has amino-terminal procollaen peptidase deficiency. Results in hyperelasicity and folds of the skin.
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What is Marfans syndrome?
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An autosomal dominant CT disorder. Characterized by abnormal elastic tissue. The fibrillin gene is defective in this disorder. (long limbs, fingers, toes result) Causes dissecting aneurysm of aorta.
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How do mast cells and plasma cells interact
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Mast cells have receptors for IgE, plasma cells make IgE in response to antigen ex:bee venom. A 2nd exposure to bee venom allows the venom to bind to adjacent IgE molecules on mast cell. Triggers mast cell degranulation.
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What are the 3 types of lymphocytes?
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B lymphocytes, T lymphocytes, Natural Killer (NK) cells. Job is to protect from invasion, see a lot in loose CTs.
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What is the function of B lymphocytes?
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Give rise to plasma cells that synthesize immunoglobulin.
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What is the function of T lymphocytes?
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Involved in cell-mediated immunity.
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What is the function of NK cells?
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Are lymphocytes that destroy virus infected cells and some tumor cells.
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