appearance of stratified squamous epithelium Location Lines the urinary bladder

Appearance of stratified squamous epithelium location

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appearance of stratified squamous epithelium Location: Lines the urinary bladder and parts of the ureters and urethra Function: Allows urinary organs to stretch as they fill with wastes while maintaining protective lining 39
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Transitional epithelium 40
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Glandular epithelium Glandular epithelium is responsible for secretion Accomplished through clusters of glandular cells that usually are deep to the covering and lining epithelium A gland may consist of one or more cells that secrete substances into ducts (hollow tubes) onto a surface, or directly into the bloodstream if no duct is present All glands are divided into two groups Endocrine glands Secrete substances called hormones into the interstitial fluid where they diffuse into the blood stream These secretions have far reaching effects (discussed in chapter 18) Exocrine glands Secrete products into ducts that empty onto the surface of covering and lining epithelium, such as the surface of the skin or into the lumen of the intestine The secretions have limited effect, and may even be harmful if they gained access to the blood Note that some glands like the pancreas have both endocrine and exocrine functions 41
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Endocrine glands 42
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Exocrine glands 43
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Classification of exocrine glands Exocrine glands can be unicellular or multicellular Unicellular glands consist on one cell that secretes their products directly onto the apical surface of a covering and lining epithelium Most exocrine glands are multicellular glands, composed of many cells arranged into distinctive microscopic structures Multicellular glands are divided based on two criteria Does the duct branch Simple glands do not branch Compound glands have branching The shape of the secretory portion of the gland Tubular – secretory portion resembles a tube Acinar- the secretory portion have a more rounded appearance Tubuloacinar – have both tubular and rounded secretory portions 44
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Simple exocrine glands 45
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Compound exocrine glands 46
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Functional classification of exocrine glands Functional classification of exocrine glands is based on how their secretions are released All forms begin with the endoplasmic reticulum and Golgi forming intracellular secretory vesicles containing the product Merocrine gland secretions are packaged by the Golgi and released from the cell in secretory vesicles via exocytosis Most common form of gland Apocrine gland secretions accumulate at the apical surface of the secreting cell; that portion of the cell then pinches off, releasing the secretion Holocrine gland secretions accumulates secretory product in the cytoplasm of the cell; when mature, the cell ruptures, releasing the secretory product 47
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Merocrine 48
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Apocrine 49
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Holocrine 50
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Connective tissue One of the most abundant and widely distributed tissues in the body Functions: Binds, supports and strengthens other tissues Compartmentalizes other tissues Transport throughout the body
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