HE 33-34 Liver Gall Bladder Pancreas

Question 1

Glissons Capsule (what and where, and surrounding lining)

Answer 1

Dense Irregular Connective Tissue

Over entire surface of liver except porta hepatis
-porta hepatis structures course between layers of hepatic duodenal ligament

Visceral peritoneum covers glissons capsul except at bare end

Question 2

Septa of liver structure and components

Answer 2

connective tissue stroma- continuous with glissons capsule.

• contains BV’s bile ducts, nerves, lymph vessels
• reticular fibers are major support unit for heptic sinusoids
• pigs;well defined septa, separate lobules
• humans; hard to delineate, and hepatic sinusoids are continuous from one lobule to the next

Question 3

parenchyma and stroma of liver

Answer 3

parenchyma: epithelial derived hepatocytes
stroma: CT support tissue (different from septa how?)

Question 4

Portal Triad definition and location

Answer 4

portal triad present gross and microscopic

Portain Vien Hepatic Artery Bile Duct

Portal area/portal canal contains microscopic of all three (at edge of hexagon lobule)-blood drains to central vein

periportal space of mall???

Triad a misnomer since lymph vessels present as well

Question 5

Hepatocytes origin and structure

Answer 5

Derived from endoderm

25% binucleate, some are polyploidy (more than two sets homologous chromosomes)

cube shape, with two sinusoidal ends and four lateral domains

20-30uM

MANY organelles

Question 6

Three classifications of liver lobules

Answer 6

Classic, acinus of rapport, portal lobe

Question 7

Classic lobule

Answer 7

central vein at center

hexagon

six portal areas in periphery

blood drains to center

bile drains to periphery

separated by septa

Question 8

Hepatic acinus of Rapport

Answer 8

distributing arterioles at center

diamond or oval shaped

two central veins

two portal areas in periphery

easily displays zones of oxygenation 1-2-3

Question 9

Portal Lobule

Answer 9

Portal area at center

triangle shaped

three central veins in periphery

bile drains to center

blood drains to periphery

Question 10

hepatocyte function based on location:

Answer 10

perivenous hepatocytes: in region of central vein (low oxygen)
LOTS of SER but no MITO (bio pathways requiring less atp) ie glycolysis, chol synthesis, FA syth, drug met)

periportal hepatocytes: in region of portal area (high oxygen)
High GA, RER (pathways requiring ATP)- protein synthesis, AA catabolism, gluconeogenesis, urea cycle)

Question 11

centralobular necrosis

Answer 11

as might occur with congestive heart failure
-or other causes of hyperfusion and hypoxia

alcohol or drug induced hepatitis also causes centrilobular necrosis

viral hepatitis causes necrosis THROUGHOUT liver lobule

Question 12

Hepatic sinusoidal Capillaries

Answer 12

Sinusoidal caps (spleen and liver)

endothelial lining of hep, sinusoids

• cells have gaps between them with no BL
• clusters of fenestrae present known as SIEVE PLATES

Question 13

Hepatocyte plate patterns

Answer 13

1 cell thick in adults

2 cells thick in children

hepatic sinusoids separate plates

blood drains from portal areas to central vein

hepatic sinusoids derived from vitelline veins

Question 14

Sinusoids lumen to hepatocyte: layers and cell types

Answer 14

Kupffer cells within lumen are macrophages derived from monocytes. Form part of sinusoid lining, unique to hepatic sinusoids

Endothelial layer.

Space of Disse: Separates sinusoidal lining cells from hepatocytes

• drains into lymph vessels at portal area
• microvilli of the hepatocytes
• intermediary space between blood and hepatocyte
• contains ITO cells

ito cell

• Hepatic stellate cell
• store fat and vitamin H
• located within perisinusoidal space

Question 15

Lateral domains, including cell types and clinical correlation

Answer 15

Contain Bile canaliculi
-create hepatic ducts
cholangiocytes:epithelial cells of biliary system
-have microvilli and long primary cilium
-cholangiocarcinoma-cancer in biliary system
intrahepatic bile duct???

Question 16

Flow of bile system in liver

Answer 16

Bile Canaliculi: spaces between hepatocytes, secreted directly here, walls formed by cell membrane (plasmellum) of hepatocyte

Flows to

intralobular bile ducts: simple cuboidal epithelium
-located at portal are an collect bile from liver lobules via intra hepatic bile ductules

flows to

R & L Hepatic ducts, exit right and left liver lobe

Question 17

Fxns of liver

Answer 17

Production of Bile : 100ml a day
-digestion and absorbtion (emulsification) of fats and elimination of cholesgterol

-bilirubin: breakdown product of hemoglobin from dead RBC
bilirubin
-bilirubin and bile pigments make up 2% of organic components of bile

-bile acid salts are 50% of the organic composition of bile

90% of bile acids are recycled
10% produced de NOVO from SER in hepatocytes

LOOK AT IMAGES ON SLIDES FOR SECRETION

Question 18

Jaundice

Answer 18

Yellow discoloration of the skin due to abnormally high amounts of bilirubin in blood
-glucuronyltransferase (conjugates H2O insoluble bilirubin forming H2O soluble bilirubin glucoronide

??

Question 19

Regulatino of blood glucose by liver

Answer 19

storage of glycogen , release of glucose in response to glucagon from pancreas (rat liver picture of glycogen being stored at 2 hour fast and then gone at 21 hr fast)

synthesis of glucose: 90% liver 10% kidney, however during acidosis or prolonged starvation gluconeogenesis shifts to kindeys: 50/50

Question 20

Gall Bladder Epithelium

Answer 20

simple columnar with microvilli

• oval shaped nuclei at base
• abundant mitochondria
• mucosal folds in empty gall bladder (full GB no folds)

Question 21

Gall bladder LP, muscularis, adventitia, and serosa

Answer 21

LP: vascular loose CT, elastic and collagen fibers
-neck of gall bladder contains glands for mucus

muscularis externa: randomly oriented muscle fibers (SMOOTH? SKELETAL?)

adventitia: LCT, attaches to flissons capsule
serosa: visceral peritoneum: over non attached surface of GB

NO MUSCULARIS MUCOSA or SUBMUCOSA

Question 22

Function of GB

Answer 22

Store/concentrate/release Bile

Question 23

path of Bile

Answer 23

hepatocyte secrete

• canaliculi
• hepatic bile ducts
• interlobular bile ducts
• common hepatic duct joins cystic duct to form bile duct
• joins main panc duct at ampulla of vater @ major duodenal papilla

Question 24

how does bile get to gall bladder

Answer 24

constriction of sphincter of bile duct prevents bile from entering duodenum and instead backs up cystic duct to GB for conc and storage

Question 25

concentration of bile

Answer 25

active transport of sodium ions and H2O follows passively (into intracellular and basally to blood stream) -inactive vs active (spaces open) states

Question 26

release of bile

Answer 26

in response to CCK (cholecystokinin) - from DNES cells of duodenum after fatty foods enter duodenum - causes simultaneous constriction of smooth muscle of gall bladder and relaxation of smooth muscle of sphincters sphincter of oddi refers to a collection of sphincters in one area...????

Question 27

Pancreas- two main cells

Answer 27

pancreatic acini: exocrine pancrease islet of Langerhans : endocrine pancreas septa derived from CT capsule and subdivides glands into lobules. septa contains Vessels, interlobular ducts and nerve fibers

Question 28

Pancreatic acini

Answer 28

``` two cells: acinar cells: -compound tubuloacinar serous glands -40-50 acinar cells per acinus -BL separates acinar cells from septa -pyramidal shape -round nucleus at base -basal cytoplasm basophilic (lots RER) -basal membranes bave receptor for CCK -apex full of secretory granules with zymogen of digestive enzymes and proenzymes (lipase, amylase, trypsin, chymotrypsin, carboxypeptidase ``` centroacinar cells: - 3-4 within the bottom, rest in intercalated duct - cuboid shape, pale nucleus - receptors for secretin from SI - alkaline fluid producers to keep enzyme inactive - intercalated ducts join the form interlobular ducts then main accessory panc ducts - cuboidal epithelium becomes columnar api in duct system

Question 29

Islets of Langerhans:

Answer 29

endocrine pancreas - one islet can contain 100's of cells , 1 million islets in the pancreas - pale staining cells, each islet HEAVILY vascularized - Mallory azan method?? - shows how reticular fibers surround each islet and the fenestrated caplillaries in the islet

Question 30

islets of Langerhans cell types

Answer 30

alpha cell: 20% of islet-periphery, produce glucagon beta cell: 70% of ilst, center, produce insulin delta cell: 5% of islet-periphery, produce somatostatin -membrane bound granules with relatively low densities

Question 31

Diabetes types

Answer 31

Type I DM: low insulin prod -formerly insulin dependent or juvenile Type II DML inability to respond to insulin -formerly non insulin dependant or adult onset Diabetes (to pass) mellitus (sweet)

Question 32

Acini vs Lang

Answer 32

acini: secretion of dig enzymes (exocrine) lang: secretion of hor from islets (endocrine )