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21 Cards in this Set
- Front
- Back
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What are some apical membrane specializations?
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Microvilli covered by a gycocalyx "sugar coat". Function is to increase surface area for absorption and secretion.
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More apical membrane specializations.
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Microfilaments in core are anchored to meshwork of microfilaments at the cell surface by a terminal web. In fluid transporting epithelia(kidney tubules), accumulations of cells with microvilli form a brush border.
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Cilia
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Hair-like, motile processes, evaginations of cell membrane. Longer than microvilli and core of microfilaments. Function is to move things over cell surface by beating in a wave-like fashion.
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Lateral and Basal Membrane Specializations
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Tight Junctions(zonula occludens)-Found only in epithelium. Band-like zone around periphery near apical border. Functions to seal surface membranes together.
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Adhering Junction
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(Zonula Adherens)-sites of strong adhesion. Can be spot-like=desmosome or macula adherens. Can be belt like=zonula adherens
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Hemidesmosomes
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Basal aspect of cell to anchor it to basal lamina (basement membrane)
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Gap Junctions
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channels that function in cell to cell communication (electrical and chemical)
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Connective Tissue
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Most abundant substance found in body. Binds things together, supports, fills spaces, repairs. Cells are far apart and surrounded by a matrix: fibers + ground substance.
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Ground substance in connective tissue matrix:
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Ranges from fluid (blood) to solid (in bone). Amphorous gel-like with high affinity for water. Proteoglycans are main component. Secreted by fibroblasts.
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Differences in connective and epithelium tissue:
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Connective tissue is highly vascular, variable cellularity, variable amount of extracellular material, surface surrounded by tissue, cell lacks basement membrane subjacent to cell, and cell membranes are nonpolar. In epithelium, they are avascular, highly cellular, almost no extracellular material, free surface, basement membrane and cell membranes are polar.
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Cell Types in Connective Tissue: What is a resident cell?
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Cells which generally stay in one area.
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Resident cells: Fibroblasts
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most common cell type in connective tissue. Mainly responsible for collagen produciton.
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Resident cells: Macrophages
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Phagocytes, attack and ingest foreign particles. Function in defense and immunity
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Resident Cells: Mast Cell
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Largest cell type: Secretes heparin-prevents blood clotting, and histamine which increases leakiness of capillaries.
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Fiber Types in Connective Tissue
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Mostly produced by fibroblasts.
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Collagen Fiber Type
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Most abundant. Very high levels in bones and dentin. Thick threads which are flexible but not elastic, high tensile strength (resists pulling force). Found in binding structures together(tendons, ligaments). Abundant collagen fibers=dense connective tissue. Few collagen fibers=loose connective tissue
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Elastic Fiber Type
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Less strength than collagen but easily stretched. Often branched and in networks. Found in elastic ligaments and arteries, vocal chords.
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Reticular Fiber Type
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Made of collagen, very thin. Mesh-like pattern of arrangement. Thin. flexible, distensible. Liver, lymphatic system. Lymphnodes
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Loose Connective Tissue
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Increased cells, decreased fibers. Delicate thin membrane (mesentary). Fills space between muscles. Adipose tissue(fat)-good example of loose CT (protects, insulates, stores energy.)
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Dense(fibrous) tissue
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decreased cells, increased fibers. Densely packed collagenous fibers with few fibroblasts. Results in very strong cords. Tendons, ligaments, deep fascia, aponeurosis. Poor blood supply, therefore slow healing
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Regular or Irregular Connective Tissue
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Dense Regular Connective Tissue found in tendon. Dense irregular found in dermis of skin.
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