Lower GI I

Question 1

What section of the small intestine are Brunner’s glands located?

Answer 1

In the duodenum

Question 2

What section of the small intestine are deep crypts of Lieberkuhn located?

Answer 2

duodenum

Question 3

What type of glands are crypts of Lieberkuhn?

Answer 3

simple tubular glands within the intestinal mucosa

Question 4

What types of cells are within the crypts of the Lieberkuhn?

Answer 4

• goblet cells
• enterocytes
• paneth cells
• enteroendocrine cells

Question 5

What cells within the crypts of Lieberkuhn secretes peptide hormones and serotonin?

Answer 5

Enteroendocrine cells

Question 6

What cells of the crypts of Lieberkuhn have prominent eosinophilic granules?

Answer 6

paneth cells of the duodenum

Question 7

What is the function of enterocytes within the crypts of Lieberkuhn?

Answer 7

• produce disaccharides
• involved in absorption of proteins, carbohydrates, and lipids
• enzymes for carbohydrate digestion
• produce enteropeptidase (enterokinase) for activation of pancreatic zymogens and proenzymes

Question 8

What 3 sections makes up the small intestine?

Answer 8

• duodenum
• jejunum
• ileum

Question 9

What type of epithelium is seen in the large intestine?

Answer 9

simple columnar without villi (they posses crypts)

Question 10

What is the function of the large intestine?

Answer 10

-secretion of mucus for lubrication
-absorption of fluid
-formation of fecal mass
continuation of digestion initiated in small intestine.

Question 11

What is appendix epiploica and where is it found?

Answer 11

masses of adipose tissue tat are enclosed within serosa. These are like fatty tags extending from the large intestine. Their purpose is unknown.

Question 12

What are taeniae coli and where are they found?

Answer 12

Longitudinal muscles arranged around the perimeter of the large intestine in 3 large bands.

Question 13

What section of the small intestine has leaflike shaped villi, include Brunner’s glands, and glands of Lieberkuhn?

Answer 13

duodenum of the small intestine

Question 14

What section of the small intestine has finger-like shaped villi, lacks glands, but includes crypts of Lieberkuhn?

Answer 14

jejunum of the small intestine

Question 15

What are Paneth cells responsible for secreting?

Answer 15

• lysozymes - degrades peptidoglycan coat of bacteria
• defensins - increases membrane permeability of target organisms.
• tumor necrosis factor - alpha - proinflammatory cytokine

Question 16

What cells secrete mucosa?

Answer 16

goblet cells

Question 17

What makes up the two layers of mucosa of the large intestine?

Answer 17

outer layer: microorganisms

inner layer: antimicrobial proteins (from paneth cells, enterocytes, and goblet cells) that resist microbial penetration

Question 18

What type of cell(s) are toll-like receptors found on ?

Answer 18

toll-like receptors are found on the surface of enterocytes.

Question 19

What is the purpose of toll-like receptors?

Answer 19

recognize structurally conserved molecules broadly shared by pathogens but distinguished from host molecules (pathogen associated molecular patterns)(PAMPS)

Question 20

Name 3 permanent structures of the GALT.

Answer 20

• appendix
• Peyer’s patches
• Mesenteric lymph nodes

Question 21

What is the purpose of high endothelial venules (HEVs) within Peyer’s patch?

Answer 21

facilitate entrance of lymphocytes into lymphoid organs from the bloodstream.

Question 22

What cells secrete IgA and where?

Answer 22

IgA is synthesized and secreted by plasma cells in the lamina propria

Question 23

Describe the rapid cell turnover mechanism within the esophagus and anus.

Answer 23

New cells are formed in basal layer of stratified epithelium and migrate through sub-basal levels to be sloughed off into the lumen.

Question 24

Describe the rapid cell turnover mechanism within the small intestine.

Answer 24

New cells are formed in the crypts from undifferentiated cells.

Question 25

What organs of the digestive system exhibit the fastest rapid cell turnover ?

Answer 25

stomach (every 5 days) and small intestine

Question 26

Where are stem cells, utilized for rapid cell turnover, found within the stomach?

Answer 26

neck of gastric glands

Question 27

What 4 types of cells may the stomach stem cells differentiate into?

Answer 27

• surface and neck mucus cells (turn over more rapidly)
• enteroendocrine cells
• parietal cells
• chief cells