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RUSOM_GI Histo III
Liver, Gallbladder, & Pancreas
Question | Answer |
---|---|
What shape is the classic liver lobule? | Hexagon (6 sides) |
What shape is the Portal lobule? | Triangle shape |
What shape is the Liver acinus? | Diamond |
What vein is found in the center of a hepatocyte? | Central v. |
What are the 3 main components of the protal triad? | Portal v., Hepatic a., Bile duct (*4th component = lymphatic tissue) |
What is the exocrine function of the liver? | It secretes bile |
What is the excretory function of the liver? | It secretes bilirubin |
What is the endocrine function of the liver? | It secretes blood-borne substances |
What type of immune cells are found in the liver? | Kupffer cells (macrophages) |
What do Kupffer cells secrete? | Lymph fluid |
When does hematopoiesis begin in the embryo? | 2nd trimester |
What is the detoxification function of the liver? | It detoxifies & breaks down fat, soluble drugs, and hormones |
Where is the portal triad located? | Each corner of a classic liver lobule |
What is a liver sinusoid? | A sinusoidal capillary that arises at the periphery of a lobule and runs between adjacent plates of hepatocytes |
Which 2 veins supply blood to the liver? | Portal vein (75%) Hepatic vein (25%) |
What is a hilus? | A depression or dissure where vesels or nerves enter an organ |
What is the route for bile flow out of the liver? | Through the bile duct to the gall bladder and then to the small intestine |
What type of blood does the portal vein supply to the liver? | O2-poor blood from the intestine (and stomach, spleen); provides nutrients and carries toxins |
What type of blood does the hepatic vein supply to the liver? | O2-blood |
In the liver, where does blood from the hepatic a/v & portal v travel? | Sinusoids |
In the liver, where does blood from the sinusoids travel? | Central v. |
In the liver, where does blood from the central v. travel? | Sublobular v. |
In the liver, where does blood from the soblobular v. travel? | Hepatic v. |
In the liver, where does blood from the hepatic v. travel? | IVC |
What other organs supply blood to the hepatic v. before it drains into the IVC? | GI organs, pancreas, spleen |
What is the source of blood for the hepatic a/v? | Abdominal aorta |
What is the source of blood for the portal v? | Alimentary canal & spleen |
What zone of the liver acini is damaged first by hepatotoxic agents? | Zone 3 |
Which zone of the liver acini is the most O2-rich? | Zone 1 |
Which zone of the liver acini is O2-poor? | Zone 3 |
Which zone of the liver acini is closest to the terminal portal v? | Zone 1 |
Which zone of the liver acini gets the highest concentration of nutrients? | Zone 1 |
Which zone of the liver acini is protected from toxins but vulnerable to anoxia? | Zone 3 |
What is anoxia? | Severe to total deprivation of O2 to tissues or organs = severe hypoxia |
Which lobule of the liver has an exocrine function? | Portal lobule |
Where is bile secreted? | Into portal lobule |
What is Glisson's capsule? | Thin, dense irregular collagenous C.T. capsule that covers the external surface of the liver |
What are the histological characteristics of hepatocytes? | High mitochondria, High RER, High SER, High Lysosomes, High Peroxisomes, High lipid droplets, High glycogen deposits, several golgi complexes; some polyploidy, some binucleated cells (25%) |
Where is the Space of Disse? | Between hepatocytes and sinusoids |
True or false: Hepatocytes are in direct contact with the bloodstream. | False. The Space of Disse connects hepatocytic endocrine secretions with the bloodstream |
What are the histological characteristics of the Space of Disse? | Contains blood plasma, microvilli of hepatocytes, reticular fibers (to maintain sinusoid structure), & some nonmyelinated nerve fibers |
In the liver acinus/Acinus of Rappaport, where is the short axis found? | Between 2 portal triads |
In the liver acinus/Acinus of Rappaport, where is the long axis found? | Between 2 central veins |
What are the 2 main functions of hepatocytes? | They produce bile & detoxify blood |
Which organ is capable or regeneration? | The liver |
What causes Cirrhosis of the liver? | Hepatic cell injury from long-term insult (ex. alcohol), leads to intense collagen secretion in the liver, followed by fibrosis, a breakdown of the lobule structure, and portal hypertension |
What cells secrete collagen in the liver? | Myofibroblasts |
What type of liver cells are APC (antigen-presenting cells)? | Kupffer cells |
What is meant by the statement that Endothelial cells are FGB? | Fenestrated, Gap, Basal lamina -- They are permeable |
What are the fat-storing cells of the liver? | ITO cells |
Where are ITO cells located? | They are stellate cells in the Space of Disse |
What do ITO cells normally store? | Vitamin A |
When there is an injury to ITO cells, what do they store? | They divide, change phenotype (to myofibroblast?) and synthesize collagen -- this leads to fibrosis |
What are the Bile Caniculi? | Small enlargement in extracellular space between 2 adjacent hepatocytes; join bile ducts in portal triad |
What seals Bile Caniculi? | Zonula occludens (gap junctions) |
What are the Canals of Hering? | Bile ductules at the periphery of classic liver lobules that receive bile from Bile Caniculi |
Where are bile ducts found? | In portal areas |
Where do bile ducts receive bile from? | Canals of Hering |
When bile ducts enlarge and fuse to form hepatic ducts, where do they leave the liver? | Porta hepatis |
What type of epithelia is found in Canals of Hering? | Squamous |
Which blood-borne substances/ plasma proteins are released as an endocrine function of the liver? | Prothrombin, fibrinogen, albumin, factor III, lipoproteins |
What is the function of the gall bladder? | Concentration, storage, and release of bile |
What is released from the small intestine upon intake of a rich meal (fats + proteins) | CCK |
What does CCK stimulate? | 1. Contraction of gall bladder, expulsion of bile into duodenum 2. Release of pancreatic enzyme |
What causes contraction of gall bladder? | 1. CCK 2. (maybe) stimulation by Ach |
What results from contraction of gall bladder and expulsion of bile into the lumen of the duodenum? | Bile is recycled in enterohepatic recirculation |
What recycles bile? | Portal vein |
Where does recycled bile go? | Liver |
What are the layers of the muscular wall in the gall bladder? | 1. Mucosa 2. Muscle layer = Muscularis externa 3. Connective tissue layer (in BRS) 4. Serosa & Adventitia |
What type of epithelia is found in the mucosal layer of the gall bladder? | Simple columnar |
What type of epithelia is found in the muscularis externa layer of the gall bladder? | Smooth m. cells |
What type of epithelia is found in the connective tissue of the gall bladder? | Dense irregular collagenous connective tissue |
What else is found in the connective tissue layer? | Nerves, blood vessels |
Most of the gall bladder is covered by ___, but around the area where the gall bladder attaches to the liver, it is covered by ___. | Serosa; Adventitia |
What 2 layers are NOT found in the gall bladder? | Muscularis mucosae, Submucosa |
What is produced by the exocrine part of the pancreas? | Digestive enzymes (trypsin, trypsin-inhibiting factors, amylase, lipase) |
Does the exocrine part of the pancreas release serous or mucus? | Serous |
What is produced by the endocrine part of the pancreas? | Hormones (Insulin, Glucagon, Somatostatin) |
What do alpha-cells in the pancreas produce? | Glucagon |
What do beta-cells in the pancreas produce? | Insulin |
What do delta-cells in the pancreas produce? | Somatostatin |
What color will Islets of Langerhans stain? | Pale-stained color |
What type of stain is used to differentiate alpha, beta, and delta cells? | H&E staining |
What do pancreatic EEC secrete? | CCK & Secretin |
What does secretin release? | Alkaline pancreatic fluid from duct cells |
What does CCK do? | Secretes bile from gall bladder, produces & releases pancreatic enzymes |
Is neural stimulation in the pancreas regulated by the sympathetic or parasympathetic nervous system? | Parasympathetic |
What is the pathway of centroacinar cells to the pancreatic duct? | 1. Centroacinar cells 2. Intercalated duct 3. Larger intralobular duct 4. Interlobular duct 5. Pancreatic duct |
What causes Type I Diabetes? | No Beta-cells = No insulin production |
What causes Type II Diabetes? | Beta cells are normal; target cells have large reduction of insulin receptors |