Accessory Organs (Liver, Pancreas, Gallbladder) Flashcards Preview

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Flashcards in Accessory Organs (Liver, Pancreas, Gallbladder) Deck (34):
1

What does the liver store?

glycogen, vit A, copper, iron

2

What does the liver produce?

albumins, lipoproteins, glycoprotiens, prothrombin

3

What does the liver metabolize?

lipid and cabs

4

What does the liver degrade?

drugs and toxins

5

What is the liver blood supply?

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

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

(blood mixes in sinusoids = vascular channels)

6

What is the direction of blood flow in the liver?

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

7

What is the direction of bile in the liver?

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

8

Hepatocytes

exocrine and endocrine; polarized, exrcetory separate from secretory

can have >1 nuceli

9

Fenestrated endothelial cells

line sinusoids. which facilitate exchange between blood and hepatocytes

10

Kupffer cells

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

11

Lipocytes (Ito cells)

fat storing cells in perisinusoidal space
store vit A

Pathology: produces ECM components --> cirrhosis

12

What are the lobular zones of the liver?

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

13

What does the apical surface of a hepatic cell face?

surface of bile canuliculi

14

What do the lateral surfaces of a hepatic cell face?

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

15

What does the basal surface of a hepatic cell face?

all/both facing sinusoids

16

Bile canaliculi

form complete loop around all 4 sides of hepatocyte

17

Canals of herin

short, transformations of bile canaliculi near portal triad

contain: hepatocytes and chorlangiocytes

18

Chorlangiocytes

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

19

Space of Disse

(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)

20

Exocrine Pancreas

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

21

Endocrine Pancreas

synthesizes and secretes hormones: insulin and glucagon
via blood stream

22

Centroacinar Cells of pancreas

beginning of intercalated ducts

23

Intercalated ducts of pancreas

~ same size as acinus
light stain

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

24

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

no striated ducts in pancreas
no myoepithelial cells in pancreas

25

Interlobular duct of pancreas

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)

26

Islets of Langerhan

endocrine
lots of FENESTRATED CAPILLARIES
NO DUCTS
light cells

27

Islets of Langerhans: What do alpha cells secrete?

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

28

Islets of Langerhans: What do beta cells secrete?

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

29

Islets of Langerhans: What do delta cells secrete?

somatostatin (inhibits sensory activities of alpha and beta cells)

30

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

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

31

What is the epithelium of the gallbladder?

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

32

How is bile concentrated?

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

33

What stimulates bile release?

CCK from duodenum --> contraction

34

Rakintasky-Ashchoff sinuses

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