The Pancreas, Liver, and Gallbladder Flashcards Preview

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Flashcards in The Pancreas, Liver, and Gallbladder Deck (69):
1

name 3 gastrointestinal digestive organs. of those, which are endocrine organs?

  • pancreas (endocrine)
  • liver (endocrine)
  • gallbladder 

2

what general functions do gastrointestinal digestive organs do?

regulate digestion and maintain metabolic homeostasis

3

what are characteristics of exocrine glands?

  • secretion onto a surface
  • made up of epithelial cells
  • diverse secretion types

4

what are characteristics of endocrine glands?

  • secretion into the vasculature
  • made up of epithelial and non-epithelial cells
  • exocytosis

5

describe the basic structure of exocrine glands

  • acinus (secretory portion) containing secretory vesicles
  • duct (conducting portion)

6

what are 3 types of exocrine glands?

  • merocrine glands
  • holocrine glands
  • apocrine glands
  • remember, it is the cells themselves within the glands that are producing the secretions

7

describe merocrine glands

  • most common exocrine gland that releases products via exocytosis at the apical end of secretory cells
  • ex. salivary glands, pancreas

8

describe holocrine glands

  • secretory cells disintegrate to form secretion
  • ex. sebaceous glands

9

describe apocrine glands

  • secretion of membrane-enclosed apical cytoplasm containing proteins and lipids
  • ex. mammary glands (also merocrine in function)

10

T or F:

the pancreas has endocrine and exocrine functions

true

11

describe the cells and the products they release of the endocrine and exocrine functions of the pancreas

  • endocrine: islets of langerhans, protein and polypeptide hormones
  • exocrine: acinar cells, releases digestive molecules into the duodenum

12

what is the function of acinar cells?

  • exocrine function in the pancreas
  • they exocytose zymogen granules into intercalated ducts

13

name 4 zymogen granules

  • alpha-amylase
  • lipases
  • nucleases
  • proteases

14

what is the function of alpha-amylase?

hydrolyze long-chain carbohydrates

15

what is the function of lipases?

hydrolyze lipids

16

what is the function of nucleases?

hydrolyze DNA and RNA

17

what is the function of protease? what is the cascade responsible for the functional process?

  • proteases are zymogens
  • they are inactive until they reach the duodenum
  • they hydrolyze proteins
  1. trypsinogen enters the duodenum; activated by enterokinase (turns trypsinogen into trypsin)
  2. activated trypsin cleaves chymotrypsinogen into chymotrypsin
  3. activeated trypsin activates elastase

18

T or F:

zymogens are activated in the liver to protect acinar cells

false:

they are activated in the duodenum to protect acinar cells

19

what are contracinar cells?

  • produce HCO3 to create an alkaline solution that flushes secretions into the duodenum

20

what 2 molecules induce acinar and contracinar exocrine activity?

  • cholecystokinin (CCK) - neuropeptide of the central and enteric nervous system; I cells
  • secretin - S cells

21

islets of langerhans include which 4 major cell types?

  • alpha cells
  • beta cells
  • delta cells
  • PP cells

22

what is the function of alpha cells?

  • islets of langerhans cell type
  • secrete glucagon
  • 30% of islet cells

23

what is the function of beta cells?

  • islets of langerhans cell type
  • secrete insulin
  • 65% of islet cells

24

what is the function of delta cells?

  • islet of langerhans cell type
  • secrete somatostatin - inhibit GI and pancreatic endocrine and exocrine secretion
  • 4% of islet cells

25

what is the function of PP cells?

  • islets of langerhans cell type
  • secrete pancreatic polypeptide - inhibits exocrine secretion, reduce GI motility, inhibit gastric acid secretion
  • <1% of islet cells

26

what are 4 main functions of the liver?

  • blood reservoir
  • bile secretion
  • detoxification
  • metabolic homeostasis

27

how does the liver function in metabolic homeostasis?

  • carbohydrate metabolism
  • lipid metabolism
  • protein metabolism
  • storage
  • serum protein production

28

the liver has vasculature coming from how many different places?

  • 2 (dual blood supply)
  • hepatic artery and portal vein
  • receives 30% of cardiac output
  • this is important in the liver's detoxification function

29

T or F:

the liver is the largest organ in the body

true

30

T or F:

the liver cannot regenerate

false:

the liver is highly regenerative

31

what are 3 major cell types of the liver?

  • hepatocyte
  • kupffer cell
  • sinusoidal epithelial cell

32

what are hepatocytes?

  • polarized epithelial cells
  • metabolism of carbohydrates, proteins, and lipids
  • produces bile from cholesterol
  • detoxifies endogenous and xenobiotic molecules

33

what are kupffer cells?

  • liver-specific macrophage
  • removes pathogens and debris from the blood
  • help prevent infection

34

what is the Couinaud system?

  • it divides the lobes of the liver into lobules
  • lobules are 3mm wide and 7mm long

35

what are sinusoidal epithelial cells?

  • line sinusoids in liver
  • large pores between cells (fenestrae)
  • no basement membrane
  • allows the liver to take on excess blood

36

describe blood flow through the liver

  • blood flows into liver via portal vein and hepatic artery
  • blood diffuses through hepatic sinusoids
  • contacts hepatocytes, kupffer cells, and sinusoidal cells
  • filtered through into bile duct or blood leaves via the central vein

37

the hepatic artery and portal vein supply the liver. what percent of the blood supply of the liver is coming from each source?

  • 70% from portal vein
  • 30% from hepatic artery

38

blood from the portal vein enters the liver, but it first drains blood from which 5 organs?

  1. stomach
  2. spleen
  3. pancreas
  4. small intestine
  5. colon

39

describe the blood flow and resistance of the liver

  • high blood flow
  • low resistance

40

which blood vessel allows first-pass metabolism?

  • portal vein
  • this allows the liver to conduct rapid assessment of dietary products

41

kupffer cells filter the blood. blood from which 2 organs does it primarily filter?

clears colon and intestinal bacteria

42

T or F:

the liver provides rapid assessment of dietary products

true

43

is the liver a blood buffer and reservoir?

  • yes
  • normal volume: 450mL
  • expansion: 0.5-1L

44

what are the 3 structure-function liver architecture classifications?

  • classic hepatic lobule
  • portal lobule
  • hepatic acinus

45

describe the classic hepatic lobule structure-function liver architecture classification

  • hexagonal prism of portal canals
  • blood drains from the portal vein and hepatic artery to the central vein
  • endocrine focus - when endocrine products are released from the liver, they are released into the central vein

46

describe the portal lobule structure-function liver architecture classification

  • bile drains from hepatocytes to the bile ducts
  • exocrine focus - production and drainage of bile

47

describe the hepatic acinus structure-function liver architecture classification

  • microvascular liver unit divided into circulatory zones
  • gradient of hepatocyte oxygenation
  • hepatic functions differ across zones

48

what are the 3 hepatic acinus zones?

  1. zone I - periportal zone; oxygen and nutrient rich; most active in regulating blood sugar and protein metabolism
  2. zone II - intermediate zone
  3. zone III - peripheral zone; oxygen poor; high concentration of detoxifying enzymes

49

the liver maintains systemic metabolic homeostasis in which 5 major ways?

  • carbohydrate metabolism
  • fatty acid metabolism
  • protein metabolism
  • storage
  • protein production

50

describe how the liver maintains metabolic homeostasis via carbohydrate metabolism 

  • glycogen storage
  • gluconeogenesis
  • normalizes blood glucose

51

describe how the liver maintains metabolic homeostasis via fatty acid metabolism 

  • oxidizes fatty acids
  • produces ketone bodies
  • synthesizes fatty acids
  • synthesizes triglycerides, phospholipids, and cholesterol
  • forms lipoproteins to transport lipids and fatty acids

52

describe how the liver maintains metabolic homeostasis via protein metabolism 

  • deaminates amino acids
  • forms urea to remove ammonia from the blood
  • synthesizes non-essential amino acids

53

describe how the liver maintains metabolic homeostasis via storage 

  • vitamins
  • fatty acids
  • iron

54

describe how the liver maintains metabolic homeostasis via protein production 

  • acute phase proteins
  • clotting factors
  • albumin
  • apolipoproteins

55

the liver detoxifies endogenous and exogenous molecules. describe phase I and II of hepatocyte xenobiotic (drug)/molecule elimination

phase I:

  • drugs/molecules converted to more polar compounds; oxidized
  • cytochrome p450 and microsomal oxidases 

phase II:

  • drugs/molecules/phase I metabolites conjugated to hydrophilic molecules
  • transferases

some drugs/molecules are directly transported into the bile
metabolites are eliminated in the bile or urine

56

what is bile?

a heterogenous liver secretion containing bile salts, cholesterol, phospholipids, bilirubins, and waste

57

bile salts are the products of what?

cholesterol metabolism

58

what cell produces bile?

hepatocytes

59

T or F:

bile is a mixed micelle solution

true

60

T or F:

bile acidifies intestinal contents

false:

it alkalanizes it

61

what is the function of bile acting as a detergent?

it solubilizes dietary lipids and fatty acids

62

bile from the liver eliminates toxic _____ waste and _____

  • endogenous
  • xenobiotics

63

describe the path bile takes from the gallbladder to the duodenum

  1. gallbladder
  2. cystic duct
  3. common bile duct
  4. merges with main pancreatic duct
  5. major duodenal papilla
  6. duodenum

64

what is the function of CCK relative to bile?

  • stimulates bile release
  • contracts gallbladder smooth muscle
  • relaxes hepatopancreatic sphincter

65

what is the function of secretin relative to bile?

  • it stimulates HCO3 secretion into the bile
  • serves to neutralize the acids from the stomach

66

what is a zymogen?

  • an inactive enzyme precursor
  • activated in the duodenum
  • activated form serves to protect acinar cells

67

in the hepatic acinus model, which zone contains hepatocytes that are most susceptible to damage during hypoxia or toxic conditions?

  • zone III
  • this region is oxygen poor and rich in detoxifying enzymes, and therefore regeneration and repair of hepatocytes here is inefficient

68

describe how bile is recycled

  • via the enterohepatic pathway
  • bile is released from the gallbladder into the duodenum
  • reuptake of bile salts into the liver
  • production of bile in the liver
  • bile stored in the gallbladder

69

list the following in order of decreasing % in bile:

chenodeoxycholic acid

lithocholic acid

deoxycholic acid

cholic acid

  • cholic acid - 50%
  • chenodeoxycholic acid - 30%
  • deoxycholic acid - 15%
  • lithocholic acid - 5%