Digestive Glands and Liver Flashcards Preview

A. White- Histology > Digestive Glands and Liver > Flashcards

Flashcards in Digestive Glands and Liver Deck (68)
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1
Q

What is the main excretory duct of the pancreas?

A

Duct of Wirsung

2
Q

What is the accessory duct of the pancreas?

A

Duct of santorini

3
Q

What type of epithelium is present in the interlobular ducts?

A

simple columnar epithelium and goblet cells

4
Q

What type of epithelium is found in the intercalated ducts?

A

Low cuboidal.

The cells also have receptors for secretin, and they secrete water and bicarbonate.

5
Q

What type of glands are acini?

A

serous glands

6
Q

What type of cells are acinar cells?

A

pyramidal serous cells.

7
Q

What is found in the apical zone of acinar cells?

A

precursors of the enzymes in pancreatic juice

Trypsin, chymotrypsin, amylase and lipase

8
Q

What type of epithelium is found in centroacinar cells?

A

cuboidal epithelium

It is continuous with the epithelium of the intercalated duct.

9
Q

What enzymes does the acinar cell release?

A

digestive enzymes. It is stimulated by CCK.

10
Q

What type of fluid is released by epithelial cells in response to secretin?

A

Bicarbonate-rich, alkaline fluid. It is released by the acinar cells.

11
Q

Where are digestive enzymes found?

A

in vesicles by the Golgi

12
Q

What is the synthesis and secretion of digestive enzymes controlled by?

A

duodenal enteroendocrine cells.

13
Q

What are digestive enzymes synthesized as?

A

Inactive proenzymes on RER of acinar cells

14
Q

Bicarbonate ion secretion is regulated by what?

A

secretin.

Bicarbonate is secreted by duodenal enteroendocrine cells when stimulated by food entering the small intestine.

15
Q

Where does carbon dioxide diffuse out of?

A

intercalated ducts from the blood.

16
Q

What are the islets of Langerhans?

A

Endocrine cell aggregations which are interspersed irregularly among the acini.

They include alpha, beta and delta cells

17
Q

What are a-cells?

A

Fine cytoplasmic granules in the islets of Langerhans that form glucagon.

18
Q

What are b-cells?

A

cells in the islets of Langerhans that produce insulin.

19
Q

What are D-cells?

A

cells in the islet of langerhans that secrete somatostatin, which helps control levels of insulin and glucagon.

20
Q

What is the general histological organization of the pancreas?

A

lobulated, compound tubulo-alveolar gland with both and exocrine and endocrine secretory function.

CT divides the gland into small lobules. The lobules contain blood vessels, lymphatics, nerves and excretory ducts.

21
Q

What is the space of disse?

A

A region that separates hepatic cells from endothelial cells.

It is active in the transfer between blood and parenchyma

22
Q

What is the space of mall continuous with?

A

The space of Disse. It drains into lymphatics.

23
Q

Glisson’s thin capsule of FECT covers the surface of the parenchyma except for what region?

A

the diaphragmatic attachment.

24
Q

What is the classic hepatic lobule?

A

A lobule with a central venule. Portal triads are at the angles.

25
Q

What is a portal lobule?

A

It has three central venules of adjacent lobules that form a triangle.

Portions of the bile of the three lobules drain into the same bile duct.

26
Q

How many zones are in the liver acinus?

A

Three zones.

They have hepatic tissue receiving blood from a branch of the hepatic artery conducting blood to opposite central veins.

27
Q

Where is the portal triad?

A

It it found at angles (corners) of the classic lobule

28
Q

What are the components of the portal triad?

A

branch of hepatic artery (arteriole)

Branch of portal vein (venule)

Bile duct (ductule)

29
Q

What is found in the cytoplasm of hepatocytes?

A

glycogen, fat droplets, and pigment granules.

30
Q

What is found in the basolateral domain of a hepatocyte?

A

microvilli

They are involved in the absorption of blood-borne substances and the secretion of plasma proteins.

31
Q

What is found in the apical domain of a hepatocyte?

A

A bile canaliculus

32
Q

What is found in the lining of hepatic sinusoids?

A

Fenestrated endothelial cells

Discontinuous basal lamina

33
Q

What are perisinusoidal cells?

A

Cells located in the space of disse that store vtamin A.

They also produce collagen fibers and extracellular matrix components.

34
Q

What happens do perisinusoidal cells during cirrhosis?

A

They transform into myofibroblasts and produce type I collagen.

35
Q

What is the subendothelial space of disse?

A

space between basal lamina and hepatocytes.

It contains microvilli, collagen, and interstitial fluid that drains into the space of Mall that drains into the lymphatics.

36
Q

What are Kupffer cells?

A

phatocytc cells derived from monocytes that line hepatic sinusoids.

37
Q

What is the bile canaliculus?

A

Extracellular canal located between two rows of hepatocytes.

It receives bile from hepatocytes.

38
Q

What is the canal of Hering?

A

a canal that receives bile from the canaliculus.

It carries bile to the bile ductule.

39
Q

What are the four components of the gallbladder?

A

Fundus

Body

Neck

Wall

40
Q

What are the three layers of the wall of the gallbladder?

A

mucosa

muscularis externa

submucosa

41
Q

What type of epithelium is found in the mucosa of the gallbladder?

A

tall columnar with a striated border

42
Q

What are Rokitansky-Aschoff sinuses?

A

small regions of the mucosa with extend into muscular and perimuscular layers.

They may indicate pathological change.

43
Q

What is found in the muscularis externa?

A

Layers of smooth muscle separated by layers of CT

44
Q

What is found in the serosa?

A

A broad, perimuscular CT coat that is rich in blood and lymphatic vessels and elastic fibers.

45
Q

What are the major ducts found in the gallbladder?

A

Cystic duct

Hepatic duct

Common bil duct

46
Q

The ducts of the mucosa are lined with what type of epithelium?

A

Columnar epithelium

47
Q

What are the afferent blood vessels found in the liver?

A

portal vein

hepatic artery

48
Q

What do branches of the portal vein enter into?

A

The lobule.

They then empty into the hepatic sinusoids.

49
Q

What do the hepatic sinusoids converge into?

A

A centeral vein (efferent vessel)

50
Q

What do the central veins unite to form?

A

A sublobular vein (tributary of the hepatic vein)

51
Q

What are some of the functions of the liver?

A

Removal of bile

Storage of glycogen

Conversion of fats and proteins to carohydrates

Amino acid deamination

52
Q

What does the liver metabolize and store?

A

fat

53
Q

What plasma proteins are stored in the liver?

A

fibrinogen, prothrombin and albumin

54
Q

What essential vitamins does the liver store?

A

A, D, B2, B3, B4, B12, K

55
Q

The liver serves as a ____ organ.

A

embryonic hematopoietic

56
Q

The liver also serves as an important organ for ___ metabolism and detoxifying ___

A

ethanol

drugs, steroids, vitamins A & D, fatty acids and carcinogens.

57
Q

What is the alcohol dehydrogenase pathway?

A

Ethanol -> acetaldehyde -> acetate

acetaldehyde is also involved in hepatocyte injury

58
Q

What organ produces and secretes hepatic bile?

A

the liver

59
Q

What are the components of bile?

A

bile acids

water and electrolytes

cholesterol and phospholipids

pirgments and organic molecules (bilirubin)

60
Q

Bilirubin is formed from what molecule?

A

Hemoglobin. It is released from damaged RBCs

61
Q

What is hemoglobin phagocytized by?

A

macrophages.

62
Q

When hemoglobin has been phagocytized by macrophages, what does it split into?

A

globin and heme

63
Q

What enzyme converts heme into biliverdin?

A

heme oxygenase

64
Q

Free bilirubin is transported attached to what protein as it travels to liver hepatocytes?

A

plasma albumin

65
Q

Once free bilirubin is released from plasma albumin, what occurs to it?

A

It is released within the liver cells and conjugated into bilirubin glucuronids (80%), bilirufin sulfate (10%) and other substances.

66
Q

Where is conjugated bilirubin secreted?

A

Into the intestine.

67
Q

What is conjugated bilirubin in the intestince converted into?

A

urobilinogen

68
Q

What are the fates of urobilinogen?

A

oxidized into excreted products OR
Reabsorbed into the blood and carried back to the liver to be

Reexcreted by the liver OR excreted in the urine.