Flashcards
Connective Tissue
Flashcards do conjunto (29)
- 1Most connective tissues originate frommesoderm, the middle germ layer of the embryonic tissue
- 2FUNCTIONS OF CONNECTIVE TISSUE- Providing structural support
- Serving as a medium for exchange
- Aiding in the defense and protection of the body
- Forming a site for storage of fat - 3how defense and protection of the body?1) the body's phagocytic cells, which engulf and destroy cellular debris, foreign particles, and microorganisms;
(2) the body's immunocompetent cells, which produce antibodies against antigens; and
(3) certain cells that produce pharmacological substances that help in controlling inflammation.
(4) Connective tissues also help protect the body by forming a physical barrier to invasion by and dissemination of microorganisms - 4which are responsible for the gel state of the extracellular matrix ?aggrecan aggregates
- 5laminin , chondlamininronectin , osteonectin and fibronectin are ?glycoproteins
- 6collagen types , where they found ?Type I: in connective tissue proper, bone, dentin, and cementum
Type II: in hyaline and elastic cartilages
Type III: reticular fibers
Type IV: lamina densa of the basal lamina
Type V: in the placenta; associated with type I collagen
Type VII: attaching the basal lamina to the lamina reticularis - 7elastin, a protein that is rich in glycine and?lysine, alanine, valine, and proline but that has no hydroxylysine
- 8The core of elastic fibers is composed of elastin and is surroundedby a sheath of microfibrils; each microfibril is about 10 nm in diameter and is composed of the glycoprotein fibrillin.
- 9what form covalent bonds with each other to form desmosine cross-links ?four lysine molecules, each belonging to a different elastin chain,
- 10The lamina reticularis aspect of the lamina densa also possessesfibronectin
- 11The lamina lucida consists mainly of the extracellular glycoproteins laminin and entactin as well as integrins and dystroglycanslaminin and entactin as well as integrins and dystroglycans
- 12Transient cells originate mainly inthe bone marrow and circulate in the bloodstream
- 13Active fibroblasts often reside in close association with collagen bundles, where they lie parallel to the long axis of the fiberdifficult to distinguish from collagen when stained with hematoxylin and eosin
- 14Although considered to be fixed cells in the connective tissues, fibroblasts are capable of some movement.These cells, however, may differentiate into adipose cells, chondrocytes (during formation of fibrocartilage), and osteoblasts (under pathological conditions).
- 15Where Myofibroblast found ?Myofibroblasts are abundant in areas undergoing wound healing, where they function in wound contraction; they also are found in the periodontal ligament, where they probably assist in tooth eruption.
- 16PericytesPericytes possess characteristics of endothelial cells and smooth muscle cells in that they contain actin, myosin, and tropomyosin, suggesting that they may function in contraction. Under certain conditions, they may differentiate into other cells.
- 17Mast cellsThe presence of numerous granules in the cytoplasm is the identifying characteristic of mast cells. These membrane-bound granules range in size from 0.3 to 0.8 μm. Because they contain heparin (or chondroitin sulfate), a sulfated glycosaminoglycan, these granules stain metachromatically with toluidine blue (i.e., toluidine blue stains the granules purple).
- 18AsthmaVictims of asthma attacks suffer from difficulty in breathing as a result of bronchospasm caused by leukotrienes released in the lungs.
- 19More active macrophages have pleats and folds in their plasma membranes as a consequence of cell movement and phagocytosisBasophilic
- 20Plasma cellsPlasma cells are derived from B lymphocytes and manufacture antibodies.
Although plasma cells are scattered throughout the connective tissues, they are present in greatest numbers in areas of chronic inflammation and in areas where foreign substances or microorganisms have entered the tissues
that have a relatively short life span of 2 to 3 weeks.
Their cytoplasm is intensely basophilic - 21Neutrophils phagocytose and digest bacteria in areas of acute inflammation, resulting in formation of pus, an accumulation of dead neutrophils and debris. Eosinophils, like neutrophils, are attracted to areas of inflammation by leukocyte chemotactic factors. Eosinophils combat parasites by releasing cytotoxins. They also are attracted to sites of allergic inflammation, where they moderate the allergic reaction and phagocytose antibody-antigen complexes.Basophils (similar to mast cells) release preformed and newly synthesized pharmacological agents that initiate, maintain, and control the inflammatory process.
Lymphocytes are present only in small numbers in most connective tissue, except at sites of chronic inflammation, where they are abundant. - 22Mesenchymal connective tissue is present only in the embryo and consists of mesenchymal cells in a gel-like, amorphous ground substance containing scattered reticular fibers the pulp of teethMucous tissue is a loose, amorphous connective tissue exhibiting a jelly-like matrix primarily composed of hyaluronic acid and sparsely populated with type I and type III collagen fibers and fibroblasts. This tissue, is found only in the umbilical cord and subdermal connective tissue of the embryo
- 23Loose connective tissue, 1) fills in the spaces of the body just deep to the skin, 2) lies below the mesothelial lining of the internal body cavity, 3) is associated with the adventitia of blood vessels, and 4) surrounds the parenchyma of glands. The loose connective tissue of mucous membranes is called the lamina propria.Because this tissue lies immediately beneath the thin epithelia of the digestive and respiratory tracts, this is where the body first attacks antigens, bacteria, and other foreign invaders. Therefore, loose connective tissue contains many transient cells responsible for inflammation, allergic reactions, and the immune response.
- 24Dense connective tissue contains a greater abundance of fibers and fewer cells than loose connective tissue.Dense irregular connective tissue constitutes the dermis of skin, the sheaths of nerves, and the capsules of the spleen, testes, ovary, kidney, and lymph nodes.
- 25Dense regular collagenous connective tissue is composed of coarse collagen bundles densely packed and oriented into parallel cylinders or sheets. Tendons, ligaments, and aponeuroses are examples of dense regular collagenous connective tissue.
- 26Dense regular elastic connective tissue The elastic fibers are arranged parallel to one another and form either thin sheets or fenestrated membranes.The latter are present in large blood vessels, ligamenta flava of the vertebral column, and the suspensory ligament of the penis
- 27Type III collagen is the major fiber component of reticular tissueliver sinusoids, adipose tissue, bone marrow, lymph nodes, spleen, smooth muscle, and the islets of Langerhans.
- 28The plasma membranes of the unilocular adipose cells contain receptors for several substances, including insulin, growth hormone, norepinephrine, and glucocorticoids, that facilitate the uptake and release of free fatty acids and glycerol.Tumors of the adipose tissues may be benign or malignant. Lipomas are common benign tumors of adipocytes, whereas liposarcomas are malignant tumors of adipocytes. The latter form most commonly in the leg and in retroperitoneal tissues, although they may form anywhere in the body. The tumor cells may resemble either unilocular adipocytes or multilocular adipocytes,
- 29. Hypertrophic obesity results from the accumulation and storage of fat in unilocular fat cells, which may increase their size by as much as four times. Hypercellular obesity, as the name implies, results from an overabundance of adipocytes. This type of obesity usually is severegood luck :)
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- FlashCards sobre Connective Tissue , criado por ehab mahajna em 13-05-2015.
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- ehab mahajna
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