WKI Sales Training Feb 2014

Chapter 14  Accessory Glands of the Gastrointestinal Tract  215

●● Contraction of these muscles (when stimulated by cholecystokinin) causes expulsion of contents of the gallbladder into the cystic duct. Adventitia and Serosa ●● The part of the gallbladder covered with peritoneum has serosa and the part not covered with perito- neum has adventitia (like other retroperitoneal organs). ●● On microscopic examination, mucosal folds of the gallbladder appear like the villi of small intestine. One of the important differentiating features is the presence of goblet cells in the mucosa of small intestine, which are absent in the gallbladder. Another differentiating feature is that in a particular region of small intestine, the size and shape of the villi are same, whereas in the gallbladder, the size and shape of the mucosal folds vary. ●● Benign tumours arising from the cells of ducts or myoepithelial cells are called pleomorphic adenoma. Warthin tumour is a benign tumour of parotid glands. Liver ●● Cirrhosis refers to irreversible chronic injury of the liver parenchyma, which results in disruption of the normal architecture of the entire liver. It is characterised by death of hepatocytes and scarring. Attempted regeneration of remaining hepatocytes results in irregular nodules, distortion of vascular architecture. Most common cause of cirrhosis of liver is alcoholic liver disease. Pancreas ●● Pancreatitis is the inflammation of the pancreas. In acute pancreatitis there is collection of inflammatory infiltrate in the stroma. Release of pancreatic enzymes can cause proteolytic digestion, haemorrhage and necrosis. It can become life-threatening. Common causes are alcoholism, gallstones, trauma, etc. Chronic pancreatitis can lead to fibrosis of the parenchyma. CLINICAL CORRELATES Salivary Glands

KEY POINTS

Basic Structure of Salivary Glands Stroma

Parenchyma (Fig. 14.1)

Duct system (Fig. 14.1)

●● Serous acini : Cells are triangular in shape with round nuclei at their bases; apical cytoplasm is eosinophilic and basal cytoplasm is basophilic ●● Mucous acini : Cells are tall with flat nuclei at their bases, empty-looking cells due to pale cytoplasm ●● Serous demilunes : Serous cells arranged as a ‘half moon’ at one end of a mucous acinus

●● Intercalated : Simple cuboidal epithelium ●● Striated : Simple cuboidal epithelium; cells have basal striations ●● Interlobular : Simple columnar epithelium in small ducts and stratified columnar epithelium in large ducts ●● Terminal part : Stratified squamous non-keratinised epithelium

Connective tissue capsule and its septa

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Different Types of Salivary Glands Gland

Secretory acini

Differentiating features

Parotid (Fig. 14.2; PMG 14.1)

Serous

Darkly stained serous acini (note that pancreas also has similar appearance, but it has islets of Langerhans)

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