Digestive System III

Question 1

Characteristics of mucous cells (4)

Answer 1

• predominant cell type in pyloric and cardiac glands
• flattened or crescent shaped nucleus
• known as mucous neck cells in the fundic gland
• cytoplasm more basophilic than surface epithelial cells

Question 2

Characteristics of gastric surface mucous cells (4)

Answer 2

• columnar in a sheet
• basal nuclei not flattened
• secrete mucins
• secrete HCO3- which neutralizes H+ before it can diffuse through

Question 3

Characteristics of parietal cells (6)

Answer 3

• found in fundic glands
• large, pyramidal shaped, and acidophilic
• tend to bulge towards periphery of gland
• contain many mitochondria
• have intracellular canaliculus with microvilli
• produce stomach acidity by pumping H+ and Cl- into the lumen

Question 4

Characteristics of chief cells (4)

Answer 4

• columnar w/ pale basophilic staining basal cytoplasm
• cell apices filled w/ zymogen granules containing pepsinogen and gastric lipase
• secrete rennin in young animals
• often zymogens are washed out, cells appear empty or foamy

Question 5

Characteristics of enteroendocrine cells (part of APUD) (5)

Answer 5

• occur sparsely throughout stomach and intestine
• contain basal granules
• occur singly, adjacent to basal lamina
• apex of cell may not reach gland lumen
• a cell may secrete more than one type of hormone

Question 6

Best known types of enteroendocrine cells

Answer 6

• argentaffin cells (serotonin)
• pancreatic alpha cells (enteroglucagon
• pancreatic beta cells (insulin)
• D-cells (somatostatin)

Question 7

Characteristics of undifferentiated cells

Answer 7

-in neck region, give rise to all cells of the gastric gland

Question 8

Characteristics of mucous cells (4)

Answer 8

• low columnar
• flattened or crescent-shaped basal nuclei
• predominant cell in cardiac and pyloric glands
• mucous neck cells in fundic gland region

Question 9

Characteristics of rumen (3)

Answer 9

• fermentation vat
• covered with paddle-shaped or tongue-like papillae
• muscularis mucosae is absent

Question 10

Characteristics of reticulum (3)

Answer 10

• important for mechanical digestion
• surface folds form honey-comb network of ridges
• small secondary papillae extend from the surface folds

Question 11

Characteristics of omasum (3)

Answer 11

• functions in mechanical digestion (grinding)
• long, leaf-like folds of varying lengths, covered w/ small horny papillae
• muscularis mucosae and T. muscularis occupy center of larger folds

Question 12

Plicae circularis

Answer 12

folds of mucosa and submucosa that are permanent in some species
increase the surface area of the jejunum in particular

Question 13

Intestinal villi

Answer 13

leaf or finger-like projections of T. mucosa in the intestines

Question 14

Central lacteal

Answer 14

blind ended lymphatic in the center of the villus which transports chylomicrons

Question 15

Intestinal mucosal glands

Answer 15

straight simple or branched tubular glands that open between villi
also called intestinal glands or crypts

Question 16

Peyer’s patches

Answer 16

aggregated lymphatic nodules

a characteristic of the ileum

Question 17

Characteristics of intestinal submucosal glands (5)

Answer 17

• found in cranial small intestine
• simple branched tubuloacinar glands
• open into base of the intestinal mucosal glands
• has secretory cells
• secretion is mucous or serous or mixed and contans protective substances to buffer stomach acid

Question 18

Intestinal mucosal barrier

Answer 18

secretions from the submucosal glands that protect the epithelium; resistant to bile acids