KP - 06 Histologi Hepar, Vesica Fellea, dan Pankreas

• Major salivary glands include the Parotid gland, Submandibular gland, and Sublingual glands.
• Minor salivary glands are located in the Labial glands, Buccal glands, and Anterior lingual glands.
• Von Ebner’s glands are located near the circumvallate papillae and are serous in nature.
• Posterior lingual glands are located at the root of the tongue and are mucous in nature.
• Palatine glands are located in the palate and are mucous in nature.
• A mixture of secretions from minor and major salivary glands is found in saliva, which contains water, ions, mucins, Ig, salivary corpuscle, desquamated epithelial cells, and also contains amylase and matase to begin digestion of some carbohydrates.
• The function of saliva is to moisturize and cleanse the oral cavity, soften ingested materials, act as a solvent to permit materials to be tasted, control bacterial populations, and help initiate sensation of thirst in decreased secretions.
• Major salivary glands secrete only in response to nervous stimulations, which are reflexive, stimulated by smell, sight or even thought of food.
• The secretory portions of major salivary glands are formed by alveoli, which may compose as serous alveoli, mucous alveoli or mixed seromucous alveoli.
• The duct system of major salivary glands includes intralobular ducts system, interlobular ducts, and major excretory ducts.
• Myoepithelial cells, also known as basket cells, lie between the limiting basement membrane and the bases of secretory cells, and may aid in expressing secretions out of secretory units into ducts systems.
• Duct systems in the submandibular gland are generally similar to the parotid gland but striated ducts are longer and more conspicuous.
• 80% of the parotid gland is composed of serous cells, 5% mucous cells, 5% striated ducts, the rest is capillaries, nerve and other ducts.
• The parotid gland is a mixed gland with a majority of secretory units being serous in humans.
• A compound tubuloalveolar gland is a structure that has a fibrous capsule with septa, lobes, lobules, myoepithelial cells and a prominent duct system.
• The submandibular gland is a composite gland, formed by a number of individual glands of variable size.
• Major excretory ducts in the parotid gland are interlobular ducts joined to form this ducts, lined by stratified squamous epithelium.
• The submandibular gland lacks a definite capsule, is covered by a thin layer of areolar connective tissue and is the second largest gland associated with the GI tract.
• Mucous alveoli in the submandibular gland are larger than serous alveoli, mucous cells is cylindrical, pale cytoplasm, basally placed oval or squamous nuclei, lumen slightly bigger.
• Each gland in the submandibular gland opens independently onto the floor of the mouth or into excretory ducts of the submandibular gland.
• In mixed seromucous alveoli, mucous alveoli is surrounded by one or more serous demilunes (crescents).
• Intralobular ducts in the first line of simple columnar epithelium become pseudostratified and then stratified as the size of the ducts increases.
• Alveoli are composed of pyramidal shaped, serous cells with basally placed oval nuclei, basophilic cytoplasm, discrete, apical secretory nodules.
• Intercellular secretory canaliculi are found in between serous cells and provide an additional route secretory products to reach the lumen.
• Intralobular ducts systems include intercalated ducts, striated ducts, and the initial segments of ducts systems.
• Striated ducts are part of the duct system of major salivary glands, with a bigger lumen, lined by columnar epithelium that show basal striations with centrally placed nuclei.
• Interlobular ducts are part of the duct system of major salivary glands, found in connective tissue between lobules.
• Portal lobule consists of hepatic tissue that is drained by bile ducts of a portal area, triangular in shape, parts of 3 adjacent hepatic lobules.
• Hepatocytes are large, polyhedral cells, ø 20 - 30 µm, arranged in plates that radiate from region of central vein.
• Endothelial cells are the major cellular element of sinusoidal lining, form discontinous endothelium.
• Bile ducts are formed by the perculation of blood through sinusoids and exit through a central vein.
• A central vein is located at each corner of a portal lobule.
• Stellate cells/kupffer cells are actively phagocytic cells, irregularly shaped, and are part of mononuclear system of macrophages, arising from monocytes of bone marrow.
• Bile canaliculi form when adjacent plasmalemma of two neighboring hepatocytes come together.
• Mucous membrane of gallbladder is a simple columnar epithelium with oval nuclei, basally placed, luminal surfaces show numerous short microvilli, and lamina propria has a small, simple tubuloalveolar glands, thought to secrete mucus.
• Wall of gallbladder consists of mucous membrane, muscularis (interlacing bundles of smooth muscle), and serosa or adventitia.
• Three types of cells are associated with the sinusoidal lining: Endothelial cells, stellate cells/hepatic macrophages/kupffer cells, and fat storing cells/lypocytes.
• Hepatic tissue is supplied by a terminal branch of hepatic artery and portal vein, and is drained by a terminal branch of bile duct.
• Common bile duct, also known as ductus choledochus, has a sphincter choledochus formed by smooth muscle, is a sac-like structure on the inferior surface of liver, may contain 30-50 ml of bile, and is 4 cm wide and 8 cm long.
• If non-distended, gallbladder forms large irregular folds (ruggae).