Lecture #36: Digestive Glands and Liver I Flashcards

1
Q

Describe the general histological organization of the pancreas.

A

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

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2
Q

What type of gland is the pancreas? Also, does it have endocrine or exocrine secretory function?

A
  • Gland -> lobulated, compound, tubulo-alveolar gland
  • Has both exocrine and endocrine secretory function
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3
Q

What does the delicate connective tissue of the pancreas contain ?

A
  • The delicated CT contains:
    • blood vessels
    • lymphatics
    • nerves
    • excretory ducts
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4
Q

What is the main excretory duct of the pancreas known as?

A

Duct of Wirsung

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5
Q

What is the name of the smaller accessory duct of the pancreas?

A

Duct of Santorini

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6
Q

What kind of epithelium are interlobular ducts of the pancreas lined with ?

A

simple columnar epithelium and goblet cells

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7
Q

What type of epithelium are intercalated ducts of the pancreas lined with?

A

low cuboidal cells

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8
Q

What do the cells of the intercalated ducts of the pancreas secrete ?

A
  • water
  • bicarbonate ion
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9
Q

What receptor for which hormone is found in cells of the intercalated duct of the pancreas?

A

cells with receptors for SECRETIN

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10
Q

Acinus Structure

A
  • Acini are serous
  • Acinar cells are pyramidal serous cells
  • Centroacinar cells
  • NO striated ducts
  • NO myoepithelial cells
  • Release of digestive enzymes from serous acinar cells is stimulated by CCK
  • Bicarbonate-rich, alkaline fluid is released by ductal epithelial cells in response to secretin
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11
Q

What is the function of acinar cells?

A
  • Acinar Cells are Pyramidal Serous Cells:
    • basal zone which is basophilic and contains nucleus and RER
    • apical zone with zymogen granules
      • precursors of the enzymes in pancreatic juice
      • trypsin, chymotrypsin, amylase, and lipase
      • specific receptors for cholecystokinin
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12
Q

What is the function of centroacinar cells?

A
  • form a truncated cuboidal epithelium within the lumen of acini
  • continuous with the epithelium of the intercalated duct
  • unique to pancreas
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13
Q

What hormone stimulates the release of digestive enzymes by serous acinar cells?

A

CCK

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14
Q

What do ductal epithelial cells release?

A

bicarbonate-rich, alkaline fluid

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15
Q

Which hormone stimulates the release of bicarbonate-rich, alkaline fluid by ductal epithelial cells?

A

Secretin

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16
Q

Do acini of the pancreas have striated ducts or myoepithelial cells?

A

NO

17
Q

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

A

peptides secreted by duodenal enteroendocrine cells

18
Q

Where are inactive proenzymes synthesized at in the pancreas?

A

Digestive enzymes are synthesized as inactive proenzymes on the RER of acinar cells.

19
Q

Where are digestive enzymes stored at in the pancreas?

A

concentrated and stored in vesicles by Golgi

20
Q

What hormone regulates the secretion of bicarbonate ions?

A

secretin

** secreted by duodenal enteroendocrine cells when stimulated by food entering the small intestine **

21
Q

What is the synthesis of bicarbonate ion mechanism?

A
  • carbon dioxide diffuses into intercalated ducts from blood
  • carbon dioxide + water –> carbonic acid (requires carbonic anhydrase)
  • carbonic acid dissociates into bicarbonate and H+
  • bicarbonate ion is actively transported to lumen of intercalated duct
  • sodium and hydrogen ions are exchanged with sodium flowing into duct lumen and hydrogen flowing into the blood
22
Q

True or False:

The intercalated duct is a continuation into the connective tissue stroma ofthe centroacinar cells.

A

True

23
Q

Which 3 cell types are found in the Islets of Langerhans in the pancreas?

A
  • A-cells (alpha cells):
    • have fine cytoplasmic granules and are presumed to form glucagon
  • B-cells (beta cells):
    • have coarse cytoplasmic granules; they are more numerous than alpha cells and produce insulin
  • D-cells (delta cells):
    • secrete somatostatin, which helps to control levels of insulin and glucagon
24
Q

Which cell type of the Islets of Langerhans of the pancreas secretes somatostatin?

A

D-cells (delta cells)

25
Q

What does somatostatin, released by delta cells in the pancreas, function to control?

A

helps to control levels of insulin and glucagon

26
Q

What do beta cells of the pancreas secrete/produce?

A

insulin

27
Q

Does alpha cells or beta cells have more numerous granules?

A

beta cells

28
Q

What does alpha cells of the pancreas form/secrete?

A

glucagon

29
Q

Which cell type found in the Islets of Langerhans in the pancres has fine cytoplasmci granules and which has coarse cytoplasmic granules?

A
  • Fine Cytoplasmic Granules = alpha cells
  • Coarse Cytoplasmic Granules = beta cells
30
Q
A