Accessory Organs (Liver, Pancreas, Gallbladder)

Question 1

What does the liver store?

Answer 1

glycogen, vit A, copper, iron

Question 2

What does the liver produce?

Answer 2

albumins, lipoproteins, glycoprotiens, prothrombin

Question 3

What does the liver metabolize?

Answer 3

lipid and cabs

Question 4

What does the liver degrade?

Answer 4

drugs and toxins

Question 5

What is the liver blood supply?

Answer 5

hepatic artery: well-oxygenated, 25% of entering blood

portal vein: rich in nutrients, wastes, and other materials (75%)

(blood mixes in sinusoids = vascular channels)

Question 6

What is the direction of blood flow in the liver?

Answer 6

blood from both hepatic artery and portal vein mix in sinusoids and flow toward central vein

Question 7

What is the direction of bile in the liver?

Answer 7

Bile is produced by hepatocyte and secreted into bile canaliculi between cells –> Flows toward bile duct

Question 8

Hepatocytes

Answer 8

exocrine and endocrine; polarized, exrcetory separate from secretory

can have >1 nuceli

Question 9

Fenestrated endothelial cells

Answer 9

line sinusoids. which facilitate exchange between blood and hepatocytes

Question 10

Kupffer cells

Answer 10

macrophages: pesudo-fixed in sinusoid; produce cytokines that stimulate fibrosis of lipocytes/ito cells/hepatic stellate cells

Question 11

Lipocytes (Ito cells)

Answer 11

fat storing cells in perisinusoidal space
store vit A

Pathology: produces ECM components –> cirrhosis

Question 12

What are the lobular zones of the liver?

Answer 12

Zone 1: (perilobular- closest to center of acinus) gets best of the blood; most active - glycogen/bile salt/lipid/cholesterol synthseis

Zone 2:

Zone 3: (centrolobular - nearest to central vein) less O2 and nutrients, first cells to die; most detox occurs here; glycogen converted to glucose - LIPID ACCUMULATION WITH CHF

Question 13

What does the apical surface of a hepatic cell face?

Answer 13

surface of bile canuliculi

Question 14

What do the lateral surfaces of a hepatic cell face?

Answer 14

opposite sides of bile duct where hepatocytes join: TJxns, adherens, etc.

Question 15

What does the basal surface of a hepatic cell face?

Answer 15

all/both facing sinusoids

Question 16

Bile canaliculi

Answer 16

form complete loop around all 4 sides of hepatocyte

Question 17

Canals of herin

Answer 17

short, transformations of bile canaliculi near portal triad

contain: hepatocytes and chorlangiocytes

Question 18

Chorlangiocytes

Answer 18

contain contractile elements which aid unidirectional bile flow toward portal canal (out of bile duct)

Question 19

Space of Disse

Answer 19

(perisinusoidal space)
space btwn hepatocyes and sinusiods

allows microvilli to project into space to material in blood can pass freely from capillary to perisinusoidal space to hepatocytes

(fenestra in walls too small for RBC passage)

Question 20

Exocrine Pancreas

Answer 20

synthesizes and secretes bicarb-rich fluid containing variety of digestive enzymes under influence of CCK secreted by DNES cells –> these secretions are transported into the duodenum via ducts

Question 21

Endocrine Pancreas

Answer 21

synthesizes and secretes hormones: insulin and glucagon

via blood stream

Question 22

Centroacinar Cells of pancreas

Answer 22

beginning of intercalated ducts

Question 23

Intercalated ducts of pancreas

Answer 23

~ same size as acinus
light stain

SECRETIN (from duodenum) triggers release of bicarb and water from intercalated ducts –> neutralize acidity of chyme

Question 24

What are two cells in salivary glands that are not in pancreas?

Answer 24

no striated ducts in pancreas

no myoepithelial cells in pancreas

Question 25

Interlobular duct of pancreas

Answer 25

lined by low columnar epithelium, surrounded by dense CT

• occasional goblet or DNES cells
• drain directly into main pancreatic duct (duct of Wirsung, herringbone-like)

Question 26

Islets of Langerhan

Answer 26

endocrine
lots of FENESTRATED CAPILLARIES
NO DUCTS
light cells

Question 27

Islets of Langerhans: What do alpha cells secrete?

Answer 27

glucagon = antagonist for insulin (15-20% of islet)

Question 28

Islets of Langerhans: What do beta cells secrete?

Answer 28

insulin = stimulus for uptake of glucose (~70% of islet)

Question 29

Islets of Langerhans: What do delta cells secrete?

Answer 29

somatostatin (inhibits sensory activities of alpha and beta cells)

Question 30

Islets of Langerhans: What do PP cells (F cells) cells secrete?

Answer 30

pancreatic polypeptide hormone = inhibits secretion and intestinal motility; stimulates gastric enzyme secretion

Question 31

What is the epithelium of the gallbladder?

Answer 31

simple columnar with short mircrovilli.

NO goblet cells, no muscularis mucosa/submucosa

mucosa usually has many folds

lamina propria: highly vascularized, loose CT with elastin and collagen

large #s of lymphocytes and plasma cells

thin, irregular muscularis externa and adventitia containing large BVs and lyphatics

Question 32

How is bile concentrated?

Answer 32

salt and water diffuse into luminal surface of cell

active fluid transport: salt pumpted from cyto and followed by water into intercellular space –> intercellular space becomes distended –> fluid moves from engorged intercellular space across basal lamina and underlying CT and into fenestrated capillaries

Question 33

What stimulates bile release?

Answer 33

CCK from duodenum –> contraction

Question 34

Rakintasky-Ashchoff sinuses

Answer 34

mucosa of gallbladder creates deep clefts, can extend through muscularis externa (look like empty circles of simple columnar epithelium

chronic inflammation can lead to gall stones