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Lab 15 – Digestive System IUSM – 2016 Slide 154: Pancreas, H&E I. Introduction II. Keywords III. Slides A. Oral Cavity 1. Lip 2. Soft palate 3. Tongue 4. Tooth B. 1. 2. 3. a. b. c. 4. Colon and 5. and C. Accessory Organs 1. Salivary Glands a. Sublingual b. Submandibular the pancreas, located adjacent to the duodenum, is a mixed exocrine and endocrine gland; it is usually readily c. Parotid identifiable by the presence of the interspersed endocrine pancreatic islets (islets of Langerhans); a thin 2. Pancreas capsule and septa divide the gland into lobules (not readily seen); the exocrine pancreas is a compound acinar 3. gland of serous acini; large amounts of adipose may be present in the septa or within the thin CT surrounding the 4. acini; interlobular ducts are lined by simple columnar epithelium and are surrounded by connective tissue IV. Summary Lab 15 – Digestive System IUSM – 2016 Slide 154: Pancreas, H&E I. Introduction II. Keywords III. Slides A. Oral Cavity serous acinus of 5-10 cells 1. Lip facing a central ; 2. Soft palate apical ends of the cells are 3. Tongue eosinophilic due to the 4. Tooth secretory granules; the basal ends are basophilic B. Gastrointestinal Tract due to the displaced 1. Esophagus nucleus and rER 2. Stomach 3. Small Intestine intralobular duct lined a. Duodenum by simple cuboidal b. Jejunum epithelium and a small c. Ileum amount of surrounding 4. Colon and Appendix connective tissue 5. Rectum and Anal Canal C. Accessory Organs 1. Salivary Glands a. Sublingual b. Submandibular serous acini of the exocrine pancreas drain into small intercalated ducts which have centroacinar cells that c. Parotid penetrate into the acini (these are a distinguishing feature of the pancreas but are often difficult to see); the 2. Pancreas intercalated ducts converge into larger intralobular ducts (there are no striated ducts within the pancreas) 3. Liver which converge into the larger interlobular ducts, within the CT septa and lined by columnar epithelium; the interlobular ducts finally drain into the main pancreatic duct which empties into the duodenum 4. Gallbladder IV. Summary Lab 15 – Digestive System Slide 50: Pancreas and Duodenum, H&E IUSM – 2016 I. Introduction II. Keywords III. Slides A. Oral Cavity 1. Lip 2. Soft palate 3. Tongue 4. Tooth B. Gastrointestinal Tract 1. Esophagus 2. Stomach 3. Small Intestine a. Duodenum b. Jejunum c. Ileum 4. Colon and Appendix 5. Rectum and Anal Canal C. Accessory Organs 1. Salivary Glands a. Sublingual b. Submandibular c. Parotid in humans, most pancreatic interlobular ducts converge to form the main pancreatic duct (of Wirsung) which 2. Pancreas combines with the common bile duct to form the ampulla of Vater, which is surrounded by a smooth muscle 3. Liver sphincter (sphincter of Oddi), of the ; the above slide lacks several of the characteristic 4. Gallbladder features of the major duodenal papilla and likely is showing the and the accessory IV. Summary pancreatic duct (of Santorini) lined with tall simple columnar epithelium Lab 15 – Digestive System IUSM – 2016 Slide 29: Liver, H&E I. Introduction II. Keywords III. Slides A. Oral Cavity 1. Lip 2. Soft palate 3. Tongue 4. Tooth B. Gastrointestinal Tract 1. Esophagus 2. Stomach 3. Small Intestine a. Duodenum b. Jejunum c. Ileum 4. Colon and Appendix 5. Rectum and Anal Canal C. Accessory Organs 1. Salivary Glands a. Sublingual b. Submandibular c. Parotid the liver is easily distinguished by the presence of the stromal portal tracts containing portal triads (branches 2. Pancreas of the hepatic proper, hepatic portal , and bile ducts); the bulkoftheparenchymaoftheliveris 3. Liver hepatocytes organized into plates of cells radiating from central (venules); the central veins which merge 4. Gallbladder into larger hepatic veins and eventually drain into the inferior vena cava IV. Summary Lab 15 – Digestive System IUSM – 2016 Slide 55 (464): Pig Liver, H&E I. Introduction II. Keywords III. Slides A. Oral Cavity 1. Lip 2. Soft palate 3. Tongue 4. Tooth B. Gastrointestinal Tract septum 1. Esophagus (not seen in humans) 2. Stomach 3. Small Intestine central vein a. Duodenum b. Jejunum c. Ileum 4. Colon and Appendix 5. Rectum and Anal Canal C. Accessory Organs 1. Salivary Glands a. Sublingual b. Submandibular c. Parotid the liver parenchyma is divided into polygonal hepatic lobules (generally hexagonal); in pigs, the lobules are 2. Pancreas demarcated by connective tissue septa providing nice visualization of the liver architecture; in humans, however, 3. Liver connective tissue in the liver is primarily confined to the portal tracts so lobules are visualized by finding a 4. Gallbladder central vein and then identifying the surrounding portal tracts containing the portal triads IV. Summary Lab 15 – Digestive System IUSM – 2016 I. Introduction Slide 29: Liver, H&E II. Keywords III. Slides A. Oral Cavity 1. Lip hepatocyte 2. Soft palate 3. Tongue branch of 4. Tooth hepatic portal vein B. Gastrointestinal Tract 1. Esophagus 2. Stomach 3. Small Intestine a. Duodenum branch of b. Jejunum hepatic artery c. Ileum 4. Colon and Appendix bile duct 5. Rectum and Anal Canal w/ simple cuboidal epithelium C. Accessory Organs 1. Salivary Glands a. Sublingual b. Submandibular c. Parotid a portal tract is the connective tissue encapsulating the portal triad which consists of three major structures: 2. Pancreas abranchofthehepatic portal vein,abranchofthehepatic artery (hepatic artery proper), and a bile duct 3. Liver (though not always appearing in a 1:1:1 ratio); lymphatic vessels (a few can be seen above) are also usually 4. Gallbladder present within the tract IV. Summary Lab 15 – Digestive System IUSM – 2016 Slide 55 (464): Pig Liver, H&E I. Introduction II. Keywords III. Slides A. Oral Cavity 1. Lip 2. Soft palate 3. Tongue 4. Tooth central vein B. Gastrointestinal Tract 1. Esophagus 2. Stomach 3. Small Intestine a. Duodenum hepatic plates b. Jejunum c. Ileum 4. Colon and Appendix 5. Rectum and Anal Canal C. Accessory Organs 1. Salivary Glands a. Sublingual b. Submandibular c. Parotid hepatic plates are cords of hepatocytes (one or two cells thick) radiating from the central vein; the plates are 2. Pancreas maintained by a meshwork of reticular fibers (type III collagen) and separated from each other by hepatic 3. Liver sinusoids; the sinusoids carry combined blood from the branches of the hepatic portal vein and the hepatic 4. Gallbladder artery in the portal tracts to the central vein IV. Summary Lab 15 – Digestive System IUSM – 2016 Slide 24: Liver & Gallbladder, Trichrome I. Introduction II. Keywords III. Slides A. Oral Cavity 1. Lip 2. Soft palate 3. Tongue 4. Tooth B. Gastrointestinal Tract 1. Esophagus 2. Stomach 3. Small Intestine central vein a. Duodenum b. Jejunum c. Ileum 4. Colon and Appendix 5. Rectum and Anal Canal C. Accessory Organs 1. Salivary Glands a. Sublingual b. Submandibular hepatic sinusoids are situated between hepatic plates and receive combined blood from the hepatic artery and c. Parotid hepatic portal vein branches within the portal tracts; the sinusoids drainintothecentral veins/venules 2. Pancreas (terminal hepatic venules); between the sinusoids and hepatocytes is a narrow space (generally seen in EMs) 3. Liver called the space of Disse into which the hepatocytes project microvilli from their basal surfaces for increased 4. Gallbladder surface area contact with the vascular contents (plasma) that leave the sinusoids into the space of Disse IV. Summary Lab 15 – Digestive System IUSM – 2016 Slide 29: Liver, H&E I. Introduction II. Keywords III. Slides A. Oral Cavity 1. Lip 2. Soft palate 3. Tongue 4. Tooth B. Gastrointestinal Tract 1. Esophagus 2. Stomach 3. Small Intestine a. Duodenum b. Jejunum c. Ileum 4. Colon and Appendix 5. Rectum and Anal Canal hepatic sinusoid C. Accessory Organs containing red blood cells 1. Salivary Glands hepatic sinusoid a. Sublingual lined with endothelial cells b. Submandibular (simple squamous epithelium) c. Parotid 2. Pancreas hepatic sinusoids can be difficult to see in routine preparations but are easily distinguished when blood cells 3. Liver are present within them; within the lumens of the sinusoids the ovoid nucleiofafewKupffer cells 4. Gallbladder (perisinusoidal macrophages) are also present; these phagocytic cells remove debris and old RBCs from the IV. Summary circulation Lab 15 – Digestive System IUSM – 2016 I. Introduction Slide 141: Liver, H&E II. Keywords III. Slides A. Oral Cavity 1. Lip 2. Soft palate 3. Tongue 4. Tooth B. Gastrointestinal Tract 1. Esophagus hepatic sinusoids 2. Stomach 3. Small Intestine a. Duodenum b. Jejunum c. Ileum hepatocyte with a large, spherical 4. Colon and Appendix nucleus (can be bi-nucleated) 5. Rectum and Anal Canal and prominent nucleolus; the C. Accessory Organs cytoplasm is generally 1. Salivary Glands eosinophilic but mottled a. Sublingual b. Submandibular c. Parotid hepatocytes are large, polygonal epithelial cells; their microvilli-lined basal surface face the sinusoids and their 2. Pancreas microvilli-lined apical surface form the bile canaliculi into which they secrete bile; they are abundant cells – not 3. Liver only in number – but in cytoplasmic contents: they have abundant rough ER and free ribosomes, abundant smooth ER and Golgi, abundant mitochondria, abundant glycogen, abundant peroxisomes, abundant lipofuscin, 4. Gallbladder and may have abundant lipids IV. Summary Lab 15 – Digestive System IUSM – 2016 Slide 24: Liver & Gallbladder, Trichrome I. Introduction II. Keywords III. Slides A. Oral Cavity 1. Lip 2. Soft palate look here to see 3. Tongue the gallbladder 4. Tooth B. Gastrointestinal Tract 1. Esophagus 2. Stomach 3. Small Intestine a. Duodenum b. Jejunum c. Ileum 4. Colon and Appendix 5. Rectum and Anal Canal C. Accessory Organs 1. Salivary Glands a. Sublingual b. Submandibular c. Parotid 2. Pancreas 3. Liver 4. Gallbladder IV. Summary Lab 15 – Digestive System IUSM – 2016 Slide 105: Gallbladder, H&E I. Introduction II. Keywords III. Slides tall simple columnar A. Oral Cavity epithelial cells, with 1. Lip no goblet cells 2. Soft palate 3. Tongue 4. Tooth ruga B. Gastrointestinal Tract 1. Esophagus 2. Stomach 3. Small Intestine a. Duodenum b. Jejunum c. Ileum 4. Colon and Appendix 5. Rectum and Anal Canal C. Accessory Organs 1. Salivary Glands a. Sublingual b. Submandibular the gallbladder is a hollow for storage and concentration of bile produced in the liver; in cross section it c. Parotid can appear similar to other “tubes” seen in lab, especially the small intestine; however, it has several defining 2. Pancreas characteristics: (1) it has rugae (transient folds of mucosa) instead of villi, (2) its epithelium lacks goblet cells, (3) 3. Liver its mucosa lacks a , (4) it does not have a well-defined layer, and (5) its muscularis 4. Gallbladder layer is not organized with the same orientations of smooth muscle as seen intheGItract IV. Summary Lab 15 – Digestive System IUSM – 2016 Common Confusion: I. Introduction Parotid Gland vs. Pancreas II. Keywords III. Slides A. Oral Cavity Parotid Gland: major salivary gland located anterior to the ear; composed almost exclusively of serous acini that produce 1. Lip a thin watery secretion rich in enzymes 2. Soft palate 3. Tongue Look for: (1) striated (intralobular) ducts are readily visible; 4. Tooth (2) surrounded by CT capsule with defined septa B. Gastrointestinal Tract 1. Esophagus 2. Stomach 3. Small Intestine a. Duodenum Parotid gland b. Jejunum c. Ileum Pancreas: exocrine and endocrine gland located in upper left 4. Colon and Appendix posterior of abdomen; exocrine portion is purely serous and 5. Rectum and Anal Canal empties into the duodenum C. Accessory Organs Look for: (1) pale-staining pancreatic islets (endocrine); (2) 1. Salivary Glands intralobular ducts are fewer and less readily seen; (3) a. Sublingual surrounded by loose CT or very thin capsule with delicate b. Submandibular septa; (4) at higher magnification, pale-staining centroacinar cells (where duct inserts into acinus) may be seen c. Parotid 2. Pancreas 3. Liver Pancreas 4. Gallbladder IV. Summary Lab 15 – Digestive System IUSM – 2016 Common Confusion: I. Introduction Pancreas vs. Spleen II. Keywords III. Slides A. Oral Cavity Pancreas: exocrine and endocrine gland located in the upper abdomen; exocrine portion is purely serous and empties into 1. Lip the duodenum 2. Soft palate 3. Tongue Lookfor:(1)exocrinegland,soductsarepresent;(2)pale- 4. Tooth staining pancreatic islets (endocrine) have homochromatic appearance; (3) at higher magnification, cells arranged in B. Gastrointestinal Tract acinar configuration 1. Esophagus 2. Stomach 3. Small Intestine a. Duodenum Pancreas b. Jejunum c. Ileum Spleen: highly-vascular abdominal organ with abundant 4. Colon and Appendix lymphoid tissue; filters the blood, providing immune 5. Rectum and Anal Canal functions and removal/destruction of old or faulty red blood cells C. Accessory Organs 1. Salivary Glands Look for: (1) no exocrine tissue, so lacks ducts; (2) white a. Sublingual pulp has heterochromatic staining, e.g., pale germinal centers b. Submandibular surrounded by dark mantle zone; (3) no acini present; (4) numerous trabeculae throughout c. Parotid 2. Pancreas 3. Liver Spleen 4. Gallbladder IV. Summary Lab 15 – Digestive System IUSM – 2016 Common Confusion: I. Introduction Small Intestine vs. Gallbladder II. Keywords III. Slides A. Oral Cavity Small intestine: largest segment of the GI tract, connecting the stomach to the ; primarily responsible for 1. Lip nutrient absorption; it has three specific segments/regions: 2. Soft palate duodenum, jejunum, and ileum 3. Tongue 4. Tooth Look for: (1) villi with fairly uniform appearance; (2) simple columnar epithelium with goblet cells; (3) muscularis B. Gastrointestinal Tract mucosae layer of mucosa; (4) defined submucosa layer; (5) 1. Esophagus muscularis externa layer has inner circular and outer 2. Stomach longitudinal layers; (6) specific segments of the small intestine may have other identifying characteristics such as 3. Small Intestine plicae circulares, Brunner’s glands, and Peyer’s patches a. Duodenum Small intestine b. Jejunum c. Ileum Gallbladder: sac-like organ which stores bile produced by 4. Colon and Appendix the liver; it concentrates the bile and releases it into the 5. Rectum and Anal Canal dudodenum after a meal C. Accessory Organs Look for: (1) mucosal folds (rugae) with varying sizes and 1. Salivary Glands arrangement; (2) tall simple columnar epithelium without a. Sublingual goblet cells; (3) lacks a muscularis mucosae layer and b. Submandibular defined submucosa; (4) muscularis externa layer has fibers arranged in longitudinal, circular, and oblique orientations c. Parotid but they do not form distinct layers 2. Pancreas 3. Liver Gallbladder 4. Gallbladder IV. Summary Lab 15 – Digestive System

IUSM – 2016 Characteristics of Segments of the Gastrointestinal Tract I. Introduction Small Intestine General Layer Specific II. Keywords Esophagus Stomach Duodenum Jejunum Ileum Large Intestine Layer III. Slides Mucosa Epithelium A. Oral Cavity 1. Lip 2. Soft palate

3. Tongue

4. Tooth Lamina B. Gastrointestinal Tract propria

1. Esophagus Muscularis 2. Stomach mucosae 3. Small Intestine a. Duodenum b. Jejunum Submucosa (w/ Meissner’s plexus) c. Ileum

4. Colon and Appendix 5. Rectum and Anal Canal Muscularis Innermost oblique C. Accessory Organs (w/ Auerbach’s plexus) 1. Salivary Glands Inner circular a. Sublingual b. Submandibular Outer longitudinal c. Parotid

2. Pancreas Serosa/Adventitia 3. Liver 4. Gallbladder IV. Summary