GI Tract + Salivary Glands B&B

Question 1

4 layers of digestive tract and their features

Answer 1

1. mucosa (innermost): epithelium + lamina propria (gastric glands in stomach) + muscularis mucosa (motility)
2. submucosa: connective tissue + Meissner’s nerve plexus
3. muscular layer: inner circular + outer longitudinal layers + Auerbach’s nerve plexus in between
4. serosa (outermost): mesothelium (lubricating) OR adventicia (retroperitoneal structures, not lubricated)

Question 2

where in stomach does stratified squamous of esophagus transition to simple columnar epithelium of stomach?

Answer 2

cardia - the neck where they meet

Question 3

where are goblet cells most abundant in the GI tract? where does their presence suggest pre-malignancy?

Answer 3

increase in number from duodenum to ileum (ileum has most)

not normally found in stomach - occur in setting of chronic inflammation (gastritis), “intestinal metaplasia” suggests pre-malignancy

Question 4

where specifically are Brunner’s glands found, and what do they do?

Answer 4

found in submucosa of duodenum - produce alkaline fluid to protect from acidic stomach fluid/chyme

gland thickness increases in peptic ulcer disease

Question 5

where specifically are Peyer’s Patches found, and what do they do?

Answer 5

found in lamina propria (mucosa) of ileum

aggregations of lymph cells, receive antigens from M cells

Question 6

intestinal erosion vs ulcer

Answer 6

erosion = mucosa only
ulcer = submucosa + muscularis mucosa

Question 7

what are the 2 nerve plexus found in the enteric nervous system, and what are their respective functions?

Answer 7

1. Meissner’s plexus: in submucosa, controls secretions/ blood flow
2. Auerbach’s plexus (myenteric plexus): between circular and longitudinal muscular layers, controls GI motility

Question 8

2 enzymes in saliva with immune functions

Answer 8

1. lysozymes - disrupt bacterial cell walls
2. lactoferrin - prevent bacterial growth (also found in breast milk)

Question 9

2 digestive enzymes found in saliva

Answer 9

1. alpha-amylase: digests carbs
2. lingual lipase: digests lipids (mostly important in newborns who have low pancreatic enzymes)

Question 10

how is the saliva produced by acinar cells modified by the ductal cells?

Answer 10

secreted as isotonic by acinar cells, but becomes hypotonic as it moves through ducts

removal of Na+ and Cl- and secretion of K+ and HCO3- —> higher pH protects against acid

with higher flow late, less time for modification, so saliva is more isotonic (but also has higher bicarb concentration due to metabolism)

Question 11

muscarinic agonist used to increase saliva production in patients with Sjögren’s syndrome

Answer 11

pilocarpine

Question 12

which pathogens (2) typically cause sialadenitis, and what antibiotics (3) are used for treatment?

Answer 12

Most often due to Staph. aureus, also often contain anaerobes

tx = nafcillin (Staph) + metronidazole or clindamycin (anaerobes)

Question 13

what cell types make up pleomorphic adenomas?

Answer 13

most common salivary gland tumor (usually benign), usually in superficial lobe of parotid gland —> painless, mobile mass at angle of jaw

made of epithelial (glandular) + stromal (cartilage) tissue

Question 14

what is a risk factor for pleomorphic adenomas?

Answer 14

benign salivary gland tumor made of epithelial + stromal tissue, usually in superficial lobe of parotid gland —> painless, mobile mass at angle of jaw

risk factor = prior radiation

can have local recurrence due to irregular margins

Question 15

what is a risk factor for Warthin’s Tumor?

Answer 15

aka Papillary Cystadenoma Lymphomatosum: salivary tumor, usually in parotid gland

risk factor = smoking

Question 16

what does histology of Warthin’s Tumor show?

Answer 16

aka Papillary Cystadenoma Lymphomatosum: salivary tumor, usually in parotid gland, smoking is risk factor

histology shows fluid-filled cysts surrounded by dense lymphoid infiltrate - may aggregate into germinal centers

Question 17

what is a risk factor for mucoepidermoid carcinoma?

Answer 17

most common malignant salivary tumor, occurs in parotids (may invade facial nerve)

risk factor = prior radiation

Question 18

what type of cells make up mucoepidermoid carcinoma?

Answer 18

most common malignant salivary tumor, occurs in parotids (may invade facial nerve)

made up of squamous + mucus cells

Question 19

smoking is a risk factor for which of the following salivary gland tumors?
a. mucoepidermoid carcinoma
b. pleomorphic adenoma
c. Warthin’s Tumor (Papillary Cystadenoma Lymphomatosum)

Answer 19

c. Warthin’s Tumor (Papillary Cystadenoma Lymphomatosum): histology shows fluid-filled cysts surrounded by dense lymphoid infiltrate - may aggregate into germinal centers