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75 Cards in this Set
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1] What is the purpose fixing tissue for micoscopic viewing?
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Fixing tissue preserves it and prevents it from deteriorating.
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2] What types of stains are used to stain tissues to be viewd with an electron microscope?
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Organic dyes are used to stain tissues under the light microscope. Heavy metal salts are used to stain tissues viewed by electron microscopes.
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For microscopic viewing describe what fixed, sections and stained mean?
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Fixed = preserved
Sections = cut into slices Stained = enhance contrast |
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3] Epithelial tissue is the only tissue type that has polarity, that is, an apical and a basal surface, why is this important?
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Epithelial tissue lines body cavities and voers the body's external surface; thus polarity with one free (apical) surface is a requirement.
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4] Which of the following properties apply to epithelial tissue? Has blood vessels, can repair itself (regenerates), cells joined by lateral contacts.
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Epithelial tissue can regenerate and its cells are joined by lateral contacts.
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Epithelial tissue
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Sheets of cells that covers body surfaces or lines body cavities. It occurs as (1) covering and lining (2) glandular epithelium.
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Special Characteristics of epithelial tissue.
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POLARITY: apical surface (exposed) basal surface (attached)
SPECIALIZED CONTACTS: Except for glandular, epithelial cells fit close to form sheets and are bound by tight junctions and desmosomes. Tight junctions keep proteins in the apical region from diffusing into the basal region and thus maintain polarity. SUPPORTED BY CONNECTIVE TISSUE: supported by the basement membrane consisting of basal and reticular lamina. AVASCULAR BUT INNERVATED: fed by diffusion from blood vesses in underlying connective tissue. REGENERATION: When apical-base polarity and lateral contacts are destroyed, eptithelial cells regenerate. |
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Basal Lamina
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Noncellular, adhesive supporting sheet consisting largely of glycoproteins secreted by epithelial cells. Acts as selective filter and scaffolding for epithelial cells to migrate to repair a wound.
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Four basic tissue types
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Muscle (movement)
Nerve (control) Connective (support) Epithelial (covering) |
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Artifacts
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Minor distortions.
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Epithelium has two names, what are they?
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First: # of cell layers present (simple=1, stratified=more than 1)
Second: shape of cells present. (squamous (flat), cuboidal, columnar) |
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Where is simple epithelia (single cell layer) typically found?
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Where absorption, secretion and filtration occur and a thin epithelial barrier is desirable.
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Where is stratified epithelia (two or more cell layers) typically found?
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High abrasion areas where protection is important such as skin surface and the linings of the mouth.
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What can help you identify squamous cells under a microscope?
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The nucleus: squamous (flattened disc), cuboidal (sphere), columnar (elongated football).
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To avoid abiguity, stratified epithelia are named according to what?
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The shape of the cells in the apical layer.
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5] Stratified epithelia are "built" for protection or to resist abrasion. Waht are the simple epithelia better at?
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Simple are built to provide for efficient absoprtion and filtration.
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6] Some epithelia are pseudostratified. What does this mean?
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Some epithelia appear to be stratified because their cells nuclei lie different distances fromt the basement membrane.
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7] Where is transitional epithelium found and what is its importance at those sites?
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Found in urinary bladder and other hollow urinary organs. The stretch of transitional epithelium allows urinary organs to handle (store or transport) a larger urine volume when necessary.
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What are simple epithelium most concerned with?
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Absorption, secretion and filtration. They are thin and poor protectors.
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Simple Squamous Epithelium
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LOOKS like tile floor, one cell thick. Thin and often permeable.
FOUND: where filtration or rapid diffusion exchange is a priority. Kidney (filtration membrane of flomeruli), Lungs (air sacs and air exchange) SPECIAL: ENDOTHELIUM: lines lymph vessels, hollow organs of CV system, capillaries (made up of endotheliium) MESOTHELIUM: "middle covering" serous membranes lining theventral body cavity and covering organs. |
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Simple Cuboidal Epithelium
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Secretion and absorption. Forms the walls fo the smallest ducts of glands and many kidney tubules.
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Simple Columnar Epithelium
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Lines digestive tract from stomach to the rectum. Absorption and secretion. GI modifications (1) microvilli on apical surface (2) secrete mucus.
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Pseudostratified columnar Epithelium
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DESCRIPTION: Single layer of cells of differing heights, some not reaching free surface; nuclei at different levels; may contain mucus secreting cells and bear cilia.
FUNCTION: Secretion (mucus), mucus propulsion by ciliary action. LOCATION: nonciliated male sperm carrying ducts and ducts of large glands, ciliated-trachea, upper respiratory tract. |
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Stratified Epithelia
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Two or more cell layers. regenrater from below; basal cells divide and push apically . More durable than simple epithelia and protection is major role.
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Stratified squamous Epithelium
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DESCRIPTION: thick membrane several layers thick; basal cuboidal or columnar and metabolically active; surface cells are flattened (squamous); In the keratinized type, surface cells full of keratin and dead; basal cells are active in mitosis.
FUNCTION: protect underlying tissue. LOCATION: Nonkeratinized types: moist linings of esophagus, mouth and vagina: keratinized-epidermis of the skin. (picture is of vagina) |
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Stratified cuboidal
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Quite rare and mostly in ducts of larger glands (sweat and mammary glands)
Typically two layers thick |
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Stratified Columnar Epithelium
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Small distribution
LOCATION: small amounts are found in the pharynx, male urethra and some glandular ducts. Occurs at transition areas or junctions between two other tpes of epithelia. Only apical layer is columnar. |
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Transitional Epithelium
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DESCRIPTION: Looks like stratified squamous and stratified cuboidal; basal cells cuboidal or columnar; suface cells dome shaped or squamouslike depending on stretch.
FUNCTION: Stretches readily and permits distension of urinary organ by contained urine. LOCATION: lines the ureters, urinary bladder, and part of the urethra. |
Cells of transitional epithelium are large and plump when the bladder is empty. When the bladder is full, they become flattened. Occasionally, a binucleate cell (black arrow) can be seen. Notice the infiltrate of lymphocytes (blue arrows) and an increased density of staining along the apical surface of the most superficial layer of epithelial cells. Is there a specialization of the plasma membrane at this surface exposed to the urine?
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Define gland
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Consists of one or more cells that make and secret a particular product called a secretion.
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What produces a secretion?
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A gland
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Differentiate between exocrine and endocrine glands.
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Endocrine is internally secreting while exocrine is externally secreting.
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Unicellular vs multicellular glands.
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Unicellular glands are scattered within eithelial sheets while multicellular glands form by invagination from the epithelial sheets and most have ducts.
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Duct
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A tubelike connection to the epithelial sheets.
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What do endocrine glands produce?
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Hormones; regulatory chemicals secreted by exocytosis directly into the extracellular space. Most are compact multicellular organs. Not all are epithelial derived. Also called ductless glands because they eventually lose their ducts.
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What secretes on to body surfaces or into body cavities?
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Exocrine glands. The unicellular glands do by exocytosis whereas the mmulticellular glands do by ducts. EXAMPLE: liver (bile), pancreas (digestive enzymes).
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Unicellular Exocrine Glands
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Mucous cells and goblet cells. Sprinkeled in the epithelial lining os the intestinal and repiratory tracts amid columnar cells. Produce mucin that when in water turns into mucus. In goblet cells the accumulation of mucin distends the top of the cell making it look like a goblet, this does not happen with mucous cells.
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Mucin and mucous
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Mucin is a complex glycoprotein that dissolves in water when secreted, once dissolved it formes mucus which protects and lubricates.
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Multicellular Exocrine Glands
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Two basic parts: duct and secretory unit (acinar). Supportive connective tissue surrounds the secretory unit and supplies it with blood vessels and nerve fibers and forms a fibrous capsule that divides the gland into lobes.
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Merocrine glands vs Holocrine glands
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Merocrine: secret by exocytosis. Cells not altered. Ex: pancreas, salivay glands, most sweat glands.
Holocrine: rupture. Ex: sebaceous (oil) glands of the skin. |
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8] What common secretion is produced by all unicellular exocrine glands?
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Mucin, which becomes mucus on mixing with water.
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9] How are multicellular exocrine glands classified?
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Classifeid by duct and secretory unit types.
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10] Which of the gland types - medrocrine or holocrine- would be expected to have the highest rate of cell division and why?
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Holocrine glands have the highest rate of cell division. The secretory cells fragment and are lost in the secretin; thus the secretory cells must be continuously replaced.
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11] What are the four functions of connective tissue?
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Bind
Support Protect Insulate Additionally, blood acts to transport substances through out the body |
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12] What are the three types of fibers found in connective tissue?
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Reticular
Collagen Elastic fibers |
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Four main classes of connective tissue:
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1) Connective tissue proper (fat and ligaments)
2) Cartilage 3) bone tissue 4) blood |
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Common characteristics of Connective Tissue
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COMMON ORIGIN: arise from mesenchyme (embryonic tissue)
DEGREES OF VASCULARITY: cartilage avascular. EXTRACELLULAR MATRIX |
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Three main elements of connective tissues:
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GROUND SUBSTANCE
FIBERS CELLS together they make up the extracellular matrix. |
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Ground Substance
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Made of; intersittial fluid, cell adhesion proteins (fibronectin, laminin) proteoglycans. Strandlike Glycosaminoglycans (GAGs) adhere to proteoglycans and look like a brush. the fibers are chondroitin sulfate and hyaluronic acid, large negatively charged polysaccharides. The higher the GAG content the more viscous the ground substance. Holds large amounts of water.
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Fibers
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Collagen: white fibers strongest,
Elastic: yellow fibers (skin, lungs, vessel walls) Reticular (reticul = network) : short fine collagenous fibers that form delitcate networks. Fuzzy nets. |
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Connective tissue cells are located in their tissue and can have tissue specific names.
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Active mitotic cells = blasts
Mature = cyte Fibroblast= connective tissue proper Chondroblast = cartilage Osteoblast = bone Hematopeoietic stem cell = blood, undifferentiated blast is not located in its tissue but in the bone marrow. |
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White blood cells
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Neutrophils
Eosinophils Lymphocytes |
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Mast cells
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Immune cells that function to detect foreign substances in the tissue spaces and initiate local inflammatory responses against them; typcially found clustere deep to an epthelium or along blood vessles.
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What are some of the chemicals carried by mast cells?
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Heparin: anticoagulant
Histamine: makes capillaries leaky. Proteases -protein degrading enzymes. |
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Macrophages
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Protective cell type common in connective tissue, lmphoid tissue and many body organs; phagoytizes tissue cells, bacteria, and other foreign debris; present antigens to T cells in the immune response. Fixed macrophages in the liver are called Kupffer cells.
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13] Which connective tissue has a soft weblike matrix capable of serving as a fluid reservoir?
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Areolar connective tissue has a loose weblike nature is capable of serving as a fluid reservoir.
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14] What type of connective tissue is damaged when you lacerate your index finger tendon?
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dense regular connective tissue is damaged when you lacerate a tendon.
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15] What type of connective tissue forms the epiphyseal plates?
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Hyaline cartilage.
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What are the four classes of connective tissue?
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1] Connective tissue proper (Six types-vary in density and types of fibers. Binding tissue. Resists mechanical stress)
2] Cartilage (Resists compression due to water in matrix. Cushion and support) 3] Bone Tissue ( Support, hard tissue that resists both compression and tension) 4] Blood (fluid, carry O2, CO2 wastes, nutrients and other substances) |
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Why is blood considered a connective tissue when it does not connect things or give mechanical support?
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It develops from mesenchyme and consists of blood cells surrounded by a nonliving fluid matrix called blood plasma.
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CONNECTIVE TISSUE PROPER
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SUBCLASSES:
Loose connective (Areolar, Adipose, Reticular) Dense Connective (Regular, Irregular, Elastic) CELLS: Fibroblasts/cytes Defense cells Fat Cells MATRIX Gel-like ground substance All three fiber types: collagen reticular, elastic. GENERAL FEATURES Six types; vary in density and types of fibers. Functions as a binding tissue. resists mechanical stress, particulary tension. |
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CARTILAGE
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SUBCLASSES:
Hyaline cartilage Elastic Cartilage Fibrocartilage CELLS Chondroblasts/cytes MATRIX Gel like ground substance Fibers: Collagen, Elastic GENERAL FEATURES Resists compression because of water held in matrix. Cushions and supports body structures. |
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16] How does the extended length of a neuron's processes aid its function in the body?
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Extended processes, a neuron can conduct electrical signals a greater distance within the body.
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17] You are looking at a muscle tissue through the microscope and you see striped branching cells that connect with one another. What are your viewing?
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Cardiac muscle cells.
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18] What muscle types are voluntary? What is injured when you pull a muscle?
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Skeletal muscle is voluntary and is pulled when exercising.
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19] What type of membrane consists of epithelium and connective tissue and lines body cavitis open to the exterior?
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Mucous membrane consists of both connective tissue and epithelium. It lines body cavities open to the exterior.
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20] What type of membrane lines the thoracic walls and covers the lungs and what is it called?
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The serous membranes called pleurae line the throax walls and cover the lungs.
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What are the three covering and lining membranes?
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Cutaneous: keratinized stratified squamous epithelium (epidermis) attached to dense irregular connective tissue (dermis) dry membrane.
Mucous Membranes: line body cavities that are open to the exterior. Underlain by the lamina propria (ones own layer) Serous Membranes: Moist membranes found in closed ventral cavities. Rests on tin layer of loose connective (aerolar) tissue. |
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Inflammatory vs immune response.
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Inflammatory is nonspecific (fast) while immune is very specific (slower).
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Repair occus in what two ways?
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fibrosis and regeneration.
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What are the relative regenerative capacities of tissues?
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VERY WELL: epithelial tissues, bone, areolar connective tissue, dense irregluar conenctive tissue and blood forming tissue.
MODERATE: Smooth muscle and dense regular connective tissue. WEAK: skeletal muscle and cartilage. NONE: Cardiac and nervous tissue. |
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21] what are the three main steps of tissue repair?
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Inflammation
Organization Regeneration and fibrosis |
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22] Why does a deep injury to the skin result in abundant scar tissue formation?
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More severe injureis damage and destroy more tissue, requiring greater replacement with scar tissue.
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23] What are the names of the three embryonic germ layers?
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Ectoderm
Mesoderm Endoderm |
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24] Which germ layer gives rise to what?
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Ectoderm = nervous system
Mesoderm = muscle and connective tissue All three = epithelium |
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What epithelial types line the following:
GI Esophagus Respiratory tract Forms alveoli Urinary tract Endothelium and mesothelium |
GI tract = simple columnar
Esophagus = stratified squamous Respiratory tract = pseudostratified ciliated columnar Forms air sacs = simple squamous Urinary tract = transitional Endothelium and mesothelium = simple squamous |
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