Pancreas, Liver, and Gallbladder Flashcards Preview

Biochemistry > Pancreas, Liver, and Gallbladder > Flashcards

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

exocrine glands

secrete onto a surface by acinus cells
epithelial cells
diverse secretions

2

endocrine

secrete into vasculature
epithelial and non-epithelial cells
exocytosis

3

what are the three types of exocrine glands

1. merocrine-salivary glands, pancreas (exocytosis)
2. holocrine- sebaceous glands (secrete disintegrated cells)
3. Apocrine (secrete large micelles) mammary glands

4

the pancreas endocrine function and exocrine function

endocrine: islets of langerhans, protein and poly. peptides hormones (insulin and glucagon)
exocrine: acinar cells (release digestive molecules into the duodenum aka enzymes)

5

the exocrine pancreas

acinar cells exocytose zymogen granules into intercalated ducts

6

zymogen granule enzymes

amylase
lipases
nucleases
proteases

7

what is trypsinogen activated by?

enterokinase cleaves trypsinogen into trypsin

8

what is chymotrypsinogen activated by?

trypsin cleaves chymotrypsinogen into chymotrypsin

9

What is elastase activate by?

trypsin

10

what do controacinar cells produce?

bicarbonate to create an alkaline soluition that flushes secretions into duodenum

11

What does Cholecystokinin (CCK) and secretin do?

induce acinar and controacinar cells activity

12

what cells release cholecystokinin(CCK) and secretin?

CCK by I cells
secretin by S cells

13

the endocrine pancreas cells

30% alpha cells: secrete glucagon
65% beta cells: secrete insulin
4% delta cells: secrete somatostatin(inhibits GI and pancreatic endo and exocrine secretes
<1% PP cells: secrete pancreatic polypeptide (inhibits pancreatic exocrine secretion, GI motility, and gastric acid secretion
% referes to amount per islet of langerhan

14

functions of the liver (4)
characteristics (3)

blood reservoir
bile secretion
detox
metabolic homeostasis
largest organ
highly regenerative
dual blood supply, receives 30% of cardiac output

15

what are the major cell types of the liver?

Hepatocyte
Kupffer
Sinusoidal epithelial cells

16

Hepatocytes

polarized epithelial cells (they are sided)
metabolism carbs, proteins, lipids
produces bile from cholesterol
detoxifies endogenous and xenobiotics

17

Kupffer cell

liver specific macs
removes pathogens and debris from the blood

18

Sinusoidal Epithelial cells

large pores between cells (fenestrae)
No basement membrane
allow large proteins to pass through them

19

how many lobes are in the liver and what is the rough size of lobules?

there are 8
3mm wide and 7 mm long

20

what are the two major sources of blood for the liver?

the hepatic artery(30%) and the portal vein(70%)

21

why is the portal vein said to allow first-pass metabolism?

blood comes from the GI and passes through the liver first.
acts as a sensor for blood concentration levels important signals

22

classic hepatic lobule modle

-hexagonal prism of portal canals
-blood drains from portal vein and hepatic artery to central vein
-endocrine function focus model

23

Portal lobule modle

bile drains from hepatocytes to the bile ducts
exocrine focus

24

hepatic acinus

microvasculature
circulatory zones
gradient of hepatocyte oxygenation
hepatic functions differ across the 3 zones

25

zone I

periportal zone, oxygen rich and nutrient rich
most active in regulating blood glucose and protein breakdown

26

zone II

intermediate zone, less oxygen and nutrients than zone I

27

zone III

peripheral zone, oxygen poor
large amount of detox enzymes
lowest blood flow
susceptible toxicity death

28

ways the liver maintains systemic metabolic homestasis

-carb metabolism
-fatty acid metabolism
-protein metabolism (deaminates AAs, makes urea)
-storage(vitamins, FAs, Iron)
-protein production (clotting factors, albumin, -apoplipoproteins)

29

liver detox phase I

Drugs/molecules converted to more polar compounds, oxidized
-cytochrome p450 and microsomal oxidases, makes drug inactivated
-makes a metabolite

30

liver detox phase II

Drugs/molecules/Phase I metabolites conjugated to hydrophilic molecules(solubilizes them)
-transferase dumps them into bile duct to be excreted
also can be dumped into blood to be sent to kidney to be urinated out

31

the liver produces bile, what is it?

a heterogeneous secretion, containing bile salts, cholesterol, phospholipids, bilirubin, and waste

32

why is bile important?

cholesterol metabolism
alkalizes intestinal contents
detergent to solubilize dietary lipids and fatty acids
eliminates toxic endogenous waste and xenobiotics
it is recycled

33

what does the gallbladder do?

it stores and secretes bile

34

what stimulates the gallbladder?

-CCK by causing SM contraction and relaxes the hepatopancreatic sphincter aka ampulla of vater
-secretin stimulates bicarbonate for the bile to be secreted in.