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Digestive gland Dr. Zahiri In the name of God. Digestive Glands Digestive glands are consist of:  Salivary glands  Pancreas  Liver  Gall bladder Dr.

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Presentation on theme: "Digestive gland Dr. Zahiri In the name of God. Digestive Glands Digestive glands are consist of:  Salivary glands  Pancreas  Liver  Gall bladder Dr."— Presentation transcript:

1 Digestive gland Dr. Zahiri In the name of God

2 Digestive Glands Digestive glands are consist of:  Salivary glands  Pancreas  Liver  Gall bladder Dr. Maria Zahiri

3 Salivary Glands minor (Accessory) salivary glands pairs of major (main) salivary glands  Three pairs of major salivary glands are: Submandibular glands Sublingual glands Parotid glands

4 Dr. Maria Zahiri Salivary Glands  capsule and septa that organize the glands into lobes and lobules

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6 Salivary Gland Cells  Serous cells  produce proteins  pyramidal cells  spherical euchromatic nucleus  Cytoplasm is basophilic (RER, Golgi apparatus)  Apically located granules that are usually eosinophilic  Many basal mitochondria

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8  Mucous cells  cuboidal or pyramidal  heterochromatic basal flattened nucleus  Apical cytoplasm is pale  They have less RER, fewer mitochondria but greater GA

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10 Organized as acinus or demilune that secrete proteins, polysaccharides and ptyalin Dr. Maria Zahiri

11 Ducts system  Intercalated duct smallest branches short, cuboidal or squamous cells and myoepithelial cells  Striated duct Larger diameter cuboidal to low columnar cells which are eosinophilic, and secrete fluid and ions basolateral membrane folded with Na – ATPase pump, elongated mitochondria

12 Dr. Maria Zahiri  intralobular ducts: Striated ducts join each other and forming intralobular ducts that are invested by more CT elements  interlobular ducts (excretory ducts): intralobular ducts join each other and forming larger caliber ducts known as interlobular ducts (excretory ducts)  Excretory duct have large diameter, large lumen, cuboidal or columnar cells, located outside of lobules

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15  Myoepithelial cells (Basket cells)  have large processes which form desmosomal contact with acini and ducts cells,  Their processes are rich in actin and myosin  have a common basal lamina with acinar cells  They attach to basal lamina by hemidesmosome

16 Dr. Maria Zahiri Parotid Gland  The largest salivary gland  produce 30% of saliva  capsule & many septa divided the glands into lobes and lobules  serous cells  After 40 year of age adipose tissue invaded the gland

17 Dr. Maria Zahiri Submandibular Gland  produce 60% of saliva  Mucous and serous acini; mucous acini with limited number of serous demilunes  About 80% of cells are serous (basophilic)

18 Dr. Maria Zahiri Sublingual Gland  It is very small that produce 5% of total saliva  Mostly mucous cells in acini with some serous demilunes  Produce mix saliva but mostly mucous saliva

19 Dr. Maria Zahiri Saliva Saliva includes water, enzymes, IgA, mucous, ions Moisten and lubricate food for swallowing Enzymes like amylase and lipase to begin digestion Saliva has protective effect on oral cavity tissues Participate in taste sensation IgA, lactoferrin, lysozyme have different role against antigens and microorganisms

20 Dr. Maria Zahiri Pancreas  is a mixed exocrine and endocrine gland  Thin capsule with septa between lobules  Exocrine part organized similar to parotid gland  Endocrine part are islets of Langerhans scattered among the excretory units  Centroacinar cells occupy the lumen of the acini, these cells are beginning of the duct system  Centroacinar cells are pale, low cuboidal  Intercalated ducts, intercalated ducts, Intralobular ducts, and interlobular ducts

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23 Liver  largest gland in the body (1500 gr)  has endocrine and exocrine functions  Receives portal blood from intestine via portal vein and oxygenated blood from hepatic arteries

24 Dr. Maria Zahiri Liver  hepatocytes  Liver has a lobular organization  Classical lobule: hepatocytes arranged as an hexagon  Portal area (triad):  is where three classical lobules are in contact with each other, more CT elements present, houses branches of hepatic artery, tributaries of portal vein, interlobular bile ducts, and lymph vessels

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26  classical lobule blood flow from periphery to center of lobule Bile flow in opposite direction in small intercellular spaces known as bile canaliculi  Portal lobule Is a triangular region that portal area is located in its center and central veins form apices of the triangle  Hepatic acinus (acinus of Rappaport) is diamond-shaped, a distributing artery located in center of acinus, three regions of parenchyma surrounding the artery(zone I, II, III)

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29 Liver  The space between the anastomosing plates of hepatocytes are occupied by hepatic sinusoids  Sinosuidal lining cells are fenestrated are not in contact with each other They prevent direct contact between blood and hepatocytes  Resident macrophages known as Kupffer cells associated with lining cells  The space that separates sinusoidal lining cells from hepatocytes is called perisinusoidal space (space of Disse)  Microvilli of hepatocytes occupy much of the space  Type III collagen that is present in space support lining cells(no basal lamina)

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31  Fat storing cells ( known as Ito cells or Stellate cells) may present in Disse space and store vitamin A  Pit cells which are natural killer cells also may be seen in space of Disse  Hepatocytes are polygonal forming anastomosing plates of one to two thickness cells, eosinophilic with 1 or 2 spherical nuclei, Cells

32  In lateral domain bile canaliculi form between two cells, microvilli, Na-K ATPase and gap junctions are common characteristics of lateral domain  Bile canaliculi between hepatocytes leading to hepatic ducts with simple cuboidal epithelium Cells

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34 Liver  Sinunosoidal domains of cell membrane have many microvilli protrude to perisinusoidal space (of Disse), endocrine secretion of hepatocytes release here  Bile secreted from hepatocytes into bile canaliculi contains water, ions, bile salts and acids, phospholipids, cholesterol, & bilirubin

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36 Liver Functions  Glycogen storage  Lipid metabolism  Vitamin storage (A, D, B 12 )  Bile production (Bile acids solubilize lipids and aid digestion)  Detoxification of drugs and toxins in SER  Synthesis of plasma proteins (albumin)  Metabolism of lipid, carbohydrate, proteins  Erythrocyte breakdown (Bilirubin formed in breakdown of RBC)  Complex IgA with secretory component

37 Gall Bladder  Mucosa : simple columnar epithelium  Epithelial layer is highly folded  lamina propria:  loose CT  Smooth muscle layer is composed of thin obliquely oriented fibers with perimuscular connective tissue  Serosal and adventitial membrane  Stores and concentrates ml bile  Cholecystokinin and acetylcholine stimulates contraction to force bile into small intestine

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39 Dr. Maria Zahiri با آرزوی روزگاری خوش


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