Exam 4: Review Questions Accessory Organs Flashcards
Liver Morphology
1) Largest Gland in the body (2-5% of body weight) 2) Glisson’s Capsule
Glisson’s Capsule
Capsule around the Liver consists of collagenous and elastic fibers
Functions of the liver
Synthesis of sugars, plasma proteins, clotting factors, lipids, urea, and ketone bodies, lipid, protein, and carbohydrate metabolism, storage of vitamins and iron, modification of hormones
Hepatocytes
Lacks a basement membrane facilitates exchange of materials with blood ( Numerous mitochondria, golgi complexes, numerous peroxisomes, glycogen deposits, lipid droplets.)
Blood Supply Liver
1) Portal vein vs 2) Hepatic artery; 1) portal vein, lobular vein, interlobular vein , inlet venules….. 2) Hepatic artery,, lobar artery, interlobular artery…. meet up at the sinusoids, central veins, sublobar veins, hepatic veins, caudal vena cava
Sinusoids
Extensive, interconnecting network of discontinuous and fenestrated capillaries located between interlobular and central veins; promotes free exchange of substances between the blood and hepatocytes
Kupffer Cells
phagocytotic cells that span the lumen of the sinusoids that create fenestrations that are crucial for exchange in sinusoids
Perisinusoidal space
A channel of varying width located between the basal surfaces of hepatocytes endothelial cells and Kupffer cells of the sinusoids; contains cells, reticular fibers, and lymph; hepatic proteins and lipoproteins are transported through the space of Disse and into the blood within the sinusoids
Lymphatic circulation
lymphatic circulation (lymph collects within the space of Disse and is transported from the central canal to a small space (space of Mall) near the interlobular veins. From here, lymph enters interlobular lymph vessels and is eventually carried to the thoracic duct.
Portal vein vs the hepatic artery
1) Portal vein 80 % of blood supply to the hepatic lobule. low in o2 content and contains metabolites and toxins ( arise from the digestive system) 2) Hepatic artery 20% of blood flow to the hepatic lobule. Contains high volumes of O2 and nutrients
Space of Disse
The perisinusoidal space is the space of DISSE!!!!!!!!!!!!!!Space located between the lumen of sinusoids and hepatocytes.
Bile components
Bile salts, acids, and pigments, and electrolytes (Na+, K+, Ca2+, Mg 2+, Cl-, HCO3-) (BAPEs)
Functions of bile
Absorption of fats and bile salts, and excretion of cholesterol, bilirubin, iron, and copper through the feces.
Biliary system
System of of channels (canaliculi) and ducts (intrahepatic and extrahepatic) that convey bile from the hepatocytes to the duodenum. Bile flow from hepatocytes near the central vein of the liver lobule.
Bile canaliculi
smallest diameter segments of biliary system; formed between adjacent hepatocytes
Biliary ductules
next segment of biliary system; formed by confluence of bile canaliculi near the interlobular connective tissue
Basic Biliary structure convergence
1) Biliary caniculi ( between hepatocytes) 2) Biliary ductules (made up of biliary caniculi that have converged. Near interlobular connective tissue 3) Interlobular bile ducts (converged interlobular biliary ducts) 4) Intrahepatic bile ducts (converged interlobular bile ducts at hilus) 5) Extrahepatic bile ducts ( continuation of intrahepatic bile ducts at the hilus) Hepatic ducts (join with cystic duct from gallbladder to form common bile duct; *In humans, a common hepatic duct is formed prior to creation of the common bile duct; ) 6) Cystic duct (duct continuing from the neck of the gallbladder; receives bile from the hepatic ducts of the liver for transport to the gallbladder
Gall bladder morphology
1) Tunica Mucosa (Simple Columnar epithelium, Mucosa exhibit deep folds, lamina propria rich in fenestrated capillaries; numerous lymphocytes and plasma cells; mucous secreting glands, neuroendocrine cells, no lamina muscularis. 2) Tunica adventitia attached to the liver/ Tunica serosa Free.
Functions of the gallbladder
Store and concentrates bile, secretes bile to the duodenum
Secretion of bile
1) CCK released from the duodenal cells in response to fatty acids, protein digestive products, and Ca2+ 2) Contraction of smooth muscle in the wall of gall bladder 3) relaxation of the sphincter of oddi of hepatopancreatic ampulla and release of bile into duodenum via the major and minor duodenal papilla
Cholelithiasis
Gall stones
Exocrine pancreas morphology
1) Covered by capsule composed of loose connective tissue 2) Trabeculae extend from the capsule, subdividing the organ into lubules 3) Compound tubuloacinar gland 4) Short simple columnar epithelial cells mostly 5)
Centroacinar cells
Squamous cells lining origin of intercalated duct within the interior of an acinus
Exocrine Pancreas Duct System
1) Intercalated Ducts (lined with low cuboidal epithelium, secretes large volume of fluid rich in electrolytes, especially Na+ and HCO3 -) 2) Intralobular ducts 3) Interlobular ducts 4) Pancreatic duct of Wirsung 5) Duct of Santorini 6) Major and minor duodenal papillae
Function of the Pancreas
1) Neutralize acidic materials (chyme) in duodenum 2) Secretion of pro-forms of enzymes needed for digestion (trypsin, chymotrypsin)
Secretin
Secreted by the neuroendocrine cells of the duodenum in response to chyme. stimulates intercalated ducts to produce large quantities of alkaline fluid (pH 8.0) rich in NaHCO3
Trypsinogen
Converted to active form, trypsin by enterokinase produced by duodenal mucosa. Digestion of proteins in chyme.
