University:
Texas A&M University
Course:
BIOL 319 | Integrated Human Anatomy and Physiology I
Academic year:

2024
Views:

199

Pages:

60
Author:

marthamanayay9qr14

Liver, gallbladder, salivary glands, and pancreas Objectives To understand the general organization of the accessory organs of the digestive system and how they contribute to obtaining metabolites necessary for growth and energy for the body. To learn the origin of these glands and how structural features of these glands contribute to their function in digestion and absorption of food stuffs Ref code # 16 Function of the Digestive System Role of liver, gall bladder, salivary glands, and pancreas Movement of food Salivary glands lubricates Secretion of digestive juices Salivary glands and pancreas secretes digestive juices and liver secretes bile Absorption of digested foods, water, and electrolytes Liver stores nutrients and cleans the blood. Also, the accessory digestive organs contribute antibodies and antibacterial/viral growth substances. ORIGIN AND DISTRIBUTION OF EPITHELIUM ECTODERM - EPIDERMIS OF SKIN AND EPITHELIUM OF CORNEA TOGETHER COVERS THE ENTIRE SURFACE OF THE BODY; SEBACEOUS AND MAMMARY GLANDS ECTODERM ENDODERM - ALIMENTARY TRACT, LIVER, PANCREAS, GASTRIC GLANDS, INTESTINAL GLANDS – ENDOCRINE GLANDS - LOSE CONNECTION WITH SURFACE MESODERM MESODERM – ENDOTHELIUM - LINING OF BLOOD VESSELS – MESOTHELIUM - LINING SEROUS CAVITIES ENDODERM ORIGIN AND DISTRIBUTION OF EPITHELIUM con’d Salivary gland 19758 155 Gallbladder Liver Histo 67 Pancreas 158 LIVER FUNCTIONS • • • • • • • • • Blood filtration - 1.2 x 107 Kupffer cells/g Blood storage - liver size and sinusoids expand Maintain normal blood glucose concentrations Metabolism and transport of lipids Secrete plasma proteins - blood clotting Nutritional metabolism and bile secretion Drug metabolism - drug tolerance Excretion of bilirubin - jaundice Secrete bile - emulsifying fats 454 Histo pig liver Human liver Classical liver lobules Separated and surrounded with connective tissue in the pig Connective tissue capsule Monkey liver Mesothelium Liver The hepatocyte functions as an endocrine-like cell (e.g., secretion of glucose and plasma proteins directly into the blood vascular system) and as an exocrine cell (e.g., secretion of bile into the bile canaliculi). This dual export of secretory products by a single cell requires a unique cellular arrangement in the liver in order to separate and compartmentalize the exocrine and endocrine-like products. Hepatocytes are arranged in fenestrated, anastomosing plates of one cell thick. Also each hepatocyte may have as many as four areas of access to the lumen. Landscape of the Hepatocyte – Four Luminal Regions (two blood and two bile) HEPATOCYTE LIVER FUNCTION - LARGEST GLAND EXOCRINE - BILE ACIDS, BILIRUBIN ENDOCRINE ALBUMIN, FIBRINOGEN, ETC. Liver Portal radicles containing: A bile duct 155 Branch of portal vein, Branch of hepatic artery Lymphatic vessel (usually) or portal canals 155 Cords of hepatocytes Liver 454 Portal radicles containing: A bile duct Branch of portal vein Branch of hepatic artery Lymphatic vessel (usually) Central vein Cords of hepatocytes CELLS OF THE LIVER HEPATOCYTEs KUPFFER CELLS ENDOTHELIAL CELLs 118 155 CELLS OF THE LIVER HEPATOCYTEs KUPFFER CELLS ENDOTHELIAL CELLs 118 155 CELLS OF THE LIVER HEPATOCYTEs KUPFFER CELLS ENDOTHELIAL CELLs 118 155 Liver hepatocyte 1. Glycogen 2. Autophagosome 3. Mitochondria EM 2 1. Hepatic sinusoid 2. Bile canaliculi 3. Space of Disse EM 18 Hepatic sinusoid Hepatic parenchymal cells with microvilli Endothelial cell projecting into sinusoid Bile canaliculi with lysosomes close by the canaliculi Liver cells EM 18 Platelet Space of Disse containing reticular fibers Dietary Differences In Amount Of Glycogen In Hepatocytes 2-hour Fast (8.2% Glycogen) 24-hour Fast (0.9% Glycogen) Liver plays a role in blood sugar concentrations on a daily basis. Sugar and protein Acinus with portal vein and artery in center ZONATION OF THE LIVER 1. Classical lobule 2. Portal lobule with triad in center 3. Acinus layers between two central veins Acinus with portal vein and artery in center Acinus If liver damage is due to a toxicant, it kills hepatocytes in Zone I first. If liver damage is due to a oxygen deprivation, it will kill the hepatocytes in Zone III first. Triad with bile duct and central vein Liver with colloidal carbon, rat Gallbladder & liver, monkey – Triad with bile duct in Liver Portal radicles : A bile duct Branch of portal vein Branch of hepatic artery HEPATOCYTEs KUPFFER CELLS ENDOTHELIAL CELLs Bile Canaliculi Bile luminal surfaces Bile duct Blood luminal surface BILE CANALICULI Stained to see the bile canaliculi as embedded in hepatocytes Bile Duct Bile canaliculus Four + compounds that are deposited/secreted into this space. a. Cholesterol b. EGF c. insulin d. IgA also bile salts and BILIRUBIN Cystic duct Portal vein Bile duct with portal vein, monkey Portal vein Cystic duct Common hepatic duct The wall of the cystic duct is convoluted and contains abundant smooth muscle fibers which represent the spiral valve preventing distention or collapse of the cystic duct when the latter is subject to sudden changes of pressure. The gallbladder stores and concentrates the bile Plasma cells 155 Mucosa elaborated by the liver In the lamina propria Simple columnar epithelium Gallbladder The mucosa is thrown into folds which project into the lumen of the gallbladder. Smooth muscle layer or branching layers Lamina propria. A thick perimuscular layer of connective tissue. Simple columnar epithelium Peritoneal serosal layer Distinguishing characteristics between the mucosa of the various parts of the stomach, intestines, and gallbladder. Mucosa = surface epithelium, lamina propera, and muscularis mucosa Cardiac stomach Fundic stomach Pyloric stomach Intestines Gallbladder SALIVARY GLANDS ACINUS = FUNCTIONAL UNIT SEROUS MUCOUS MIXED Origin of Salivary Glands? • Ectoderm - oral ectoderm epithelial sheet • Endoderm - alimentary tract Saliva Helps Prevents Infections Contains secreted IgA Contains Lactoferin - bind up iron needed for bacteria division Contains lysosome that kills bacteria Constantly washes mouth to dislodge and sweep bacteria down GI tract Salivary Glands Salivary Glands Ducts of Salivary Glands Intercalated Striated 19758 Submandibular gland - intercalated duct runs into Striated duct of salivary gland The salivary gland is a compound, tubuloacinar gland. Striated Ducts These striations reflect vertically arranged mitochondria associated with deep infoldings of the basal plasma membrane Secretory acini Intercalated ducts Salivary gland Secretory acini are drained by intercalated ducts and join striated ducts Serous and mucous acini Myoepithelial cells Salivary gland Striated ducts drain into a series of interlobular ducts Serous and mucous acini Demilune Lobules Artery Adipose cells Vein Individual secretory acini are drained by intercalated ducts and join striated ducts Interlobular ducts Salivary glands Lobules Myoepithelial cells 440 Nerve cell bodies Histo 52 Striated ducts Serous and mucous acini Nerve 19758 Ref code #5 Pancreas PANCREAS FUNCTION 1. EXOCRINE 2. ENDOCRINE HISTOLOGICAL ORGANIZATION, EXOCRINE PORTION 1. ACINI 2. DUCTS ENDOCRINE PORTION • ISLETS OF LANGERHANS HISTOPHYSIOLOGY 156 and 157 Pancreas 157 Ref code #6 156 Intercalated duct 36723 Secretory granules All acini are of the serous type and many contain centroacinar cells initiate the duct inside the acinus. 157 Pancreas - Islets of Langerhans The pancreas is a compound tubuloalveolar (tubuloacinar) gland which functions in the digestion of food. Lobes composed Intercalated duct Insulin is secreted by the B cells which are most numerous and centrally located in the islets. Islets of Langerhans of lobules Connective tissue septa. Blood vessels Nerve Interlobular duct Pancreatic acinar cell (EM 1) 1. Lumen 2. Zymogen granule 3. Vesicles 4. Central acinar cell EM 1 36723 Beginning of intercalated ducts Intercalated duct Islets of Langerhans Interlobular duct In summary Questions on the Liver, pancreas, and salivary glands The humoral activity of the immune system is illustrated by the transfer of IgA immunoglobin by epithelial cells into which of the following body fluids? a. saliva b. milk c. bile d. a and b e. a, b, and c Which function(s) do the gallbladder and urinary bladder have in common? a. temporary storage of waste products b. concentration of their respective luminal contents c. similar type of luminal epithelium d. a and b e. a, b, and c Characteristics of the pancreas include: a. a portal blood vascular system b. endocrine cells of the islets of Langerhans c. acinar cells and striated ducts d. a and b e. a, b, and c

Liver, Gallbladder, Salivary Glands, and Pancreas

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