Liver, Gall Bladder, And Pancreas

Question 1

Liver

Answer 1

. Metabolism of carbs, protein, and fat, modification of exogenous substances and formation and secretion of bile

Question 2

Major functions of liver

Answer 2

. Fat metabolism: beta oxidation, synthesis of plasma lipoproteins, cholesterols, and phospholipids
. Carb metabolism: regulating glucose, converting carbs and proteins into FA
. Protein metabolism: synthesis of plasma proteins and non-essential amino acids
. Storage of glycogen, vitamins, iron
. Detoxification of metabolic waste products, drugs, and toxins
. Synthesis and secretion of bile

Question 3

Liver blood supply

Answer 3

. Hepatic portal vein (80% blood supply) brings oxygen-poor blood from GI tract that contains nutrients and toxins from intestines, blood cells, and breakdown products from spleen and endocrine secretions from pancreas and intestines
. Hepatic aa. (20% blood supply): bring O2-rich blood

Question 4

Basic structure of liver

Answer 4

. 80% liver tissue is parenchyma w/ hepatocytes arranged in stacks separated by fine blood sinusoids
. 20% CT stroma

Question 5

Classic lobules

Answer 5

. Considered morpho-functional unit of the liver
. Central vein at center
. Portal triads (artery, vein, bile ductule) in pentagonal shape along w/ lymph vessel
. CT continuous w/ fibrous capsule of liver
. Sinusoids radially arranged that move mixed blood from portal CT area to central vein

Question 6

Space of disse

Answer 6

. Perisinusoidal space
. Btw discontinuous sinusoidal epithelium and hepatocytes
.allows for exchanges btw hepatocyte and circulating blood in sinusoid
. Allows exocrine and endocrine roles of hepatocyte to take place and modify blood composition as it circulates in sinusoid

Question 7

Venous drainage of liver

Answer 7

. Central vein to larger veins to 2+ hepatic vv. To IVC

Question 8

Hepatocyte

Answer 8

. Polygonal shape w/ euchromatic nucleus (can be binucleated)
. Glycogen granules and lipids
. 2 surfaces face perisinusoidal space
. Other 4 surfaces btw adjacent plasma membranes of hepatocytes w/ bile canaliculus
. Micovilli of 2 adjacent hepatocytes extend into canalicular lumen to reverse the bile
. Network of bile canaliculi continues through plates of hepatocytes

Question 9

Bile canaliculus

Answer 9

. Space isolated from rest of intercellular compartment by junctional complexes (tight junctions, zonula adherentes and desmosomes) preventing escape of bile
. Walls formed by plasmalemma of adjacent hepatocytes

Question 10

Bile flow system

Answer 10

Centrifugal
. Bile canaliculus transforms into short canal of Hering that exhibits contractile activity for unidirectional flow toward portal area
. canal of Hering drain into bile ductules that carry bile to interlobular (intrahepatic) bile duct
. Interlobular ducts drain into R and L hepatic ducts then the common duct and then common duct to duodenum

Question 11

Epithelium of bile ductule

Answer 11

. Simple cuboidal epithelium

Question 12

Portal lobule

Answer 12

. Based on Bile drainage
. Triangle friend by bile ductule.
. 3 central veins at each corner
. Bile ductule in center

Question 13

Liver acinus

Answer 13

. Based on blood supply 
. Hepatic tissue supplied by terminal branch of hepatic a. And portal hepatic v. 
. Diamond shaped 
. Central veins at 2 opposite corners 
. 2 portal triads at 2 opposite corners

Question 14

Gall bladder function

Answer 14

. Storage of bile
. Concentration fo bile
. Release of bile through contraction of smooth muscle through CCK

Question 15

CCK

Answer 15

. Produced by neuroendocrine cells in duodenal mucosa

Question 16

Gall bladder structure

Answer 16

. Hollow connected by cystic duct to common hepatic duct to form common bile duct
. Mucosa w/ irregular folds, simple columnar epithelium w/ no goblet cells, lamina propria w/ numerous fenestrated capillaries and venules that underlie epithelium
. No muscularis mucosae and submucosa
. Muscularis externa irregular in thickness and orientation
. Adventitia where gall bladder contacts liver, serosa where it is covered by peritoneum

Question 17

Pancreas basic structure

Answer 17

. Lobulated gland covered by CT capsule

. Sends septa (trabeculae) separating that pancreas into lobules

Question 18

Exocrine portion of pancreas

Answer 18

. Forms bulk of pancreas
. Secreted alkaline fluid, containing digestive enzymes into duodenum
. Made of serous secretory acini

Question 19

Endocrine portion of pancreas

Answer 19

. Isolated clusters of endocrine cells scattered throughout exocrine tissue

Question 20

Pancreas secretory acini

Answer 20

. Irregular cluster of pyramid-shaped secretory cels
. Apices of secretory cells surround minuscule central lumen starting duct system
. Cells contain RER, golgi, zymogenic granules in apical portion
. Basophilic cytoplasm and active nucleus at base of cell

Question 21

What do pancreatic acinar cells secrete?

Answer 21

. Precursors of amylase, lipases, endopeptidases (trypsin and chymotrypsin) and exopeptidases (carboxypeptidases A and P), and bicarbonate

Question 22

Secretin

Answer 22

Produced by neuroendocrine cells in duodenum promotes secretion of alkaline fluid

Question 23

Gastrin

Answer 23

. Produced by neuroendocrine cells of gastric pyloric has similar CCK function

Question 24

ANS function in pancreas

Answer 24

Modulates secretory activity

Question 25

Pancreatic duct system

Answer 25

. Centroacinar cells In lumen of acinus form 1st par of duct system
. Continuous w/ intercalated ducts
. Intercalated marges to intralobular
. Merge to interlobular in CT septa btw lobules
. No striated ducts

Question 26

Endocrine pancreas

Answer 26

. Spheroid also masses of pale-staining cells called islets of langerhans w/ rich blood supply
. Scattered throughout pancreas
. Alpha cells: 20% of cells, glucagon
. Beta cells: 70% islet cells, produce insulin
. Delta cells: 10% of islet cells, produce somatostatin