Histology

Question 1

name the three sections of small intestine in order from proximal to distal

Answer 1

duodenum, jejunem, ileum

Question 2

what are plicae circulares? where are they found?

Answer 2

permanent mucosal folds present in small intestine

Question 3

what are villi? where are they found?

Answer 3

projections of epithelium-covered lamina propria present in small intestine

Question 4

what are microvilli? where are they found?

Answer 4

extensions of the epithelial cell apical plasma membrane present in small intestine

Question 5

what is a lacteal?

Answer 5

central lymphatic channel of villi present in small intestine

Question 6

epithelial covering of villi of small intestines are composed of what 3 types of cells?

Answer 6

1. absorptive cells (enterocytes)
2. goblet cells
3. DNES (enteroendocrine) cells

Question 7

3 types of cells in Crypts of Lieberkuhn of small intestines

Answer 7

1. DNES (enteroendocrine) cells
2. stem cells
3. Paneth cells

Question 8

what type of cells are enterocytes of the small intestine?

Answer 8

columnar epithelial cells

Question 9

functions of enterocytes of the small intestine: general and fat-related

Answer 9

general: terminal digestion and absorption of water and nutrients, transport nutrients into lamina propria for distribution to rest of body
fat: re-esterify fatty acids into TGs and form chylomicrons

Question 10

role of glycocalyx covering of microvilli in small intestine

Answer 10

1. protective

2. involved in digestion of disacccharides and dipeptides into monomers for absorption

Question 11

role of goblet cells

Answer 11

secrete mucin

Question 12

distinguish the upper and basal half of the crypts of the small intestine

Answer 12

upper: surface absorptive and goblet cells
basal: regenerative cells, DNES (enteroendocrine) cells and Paneth cells

Question 13

role of Paneth cells in small intestine

Answer 13

secrete lysozyme and defensins

Question 14

which cells in the small intestine do not participate in upward migration of epithelial cells?

Answer 14

Paneth cells

Question 15

what does the lamina propria of the small intestine contain?

Answer 15

1. blood vessels: highly vascularized to accept the products of absorption
2. lymphoid cells

Question 16

in what tunic is GALT located?

Answer 16

lamina propria

Question 17

what part of the small intestine has the most Peyer’s patches? (rank from high to low)

Answer 17

ileum > jejunum > duodenum

Question 18

what part of the small intestine has Brunner’s glands? in what tunic?

Answer 18

submucosa of duodenum

Question 19

role of Brunner’s glands

Answer 19

secrete alkaline mucus that neutralizes pH of gastric chyme and protects the duodenum

Question 20

2 methods of regulation of secretion in small intestine

Answer 20

1. submucosal (Meissner’s) plexus

2. hormones produced by enteroendocrine cells

Question 21

where are CCK and secretin secreted?

Answer 21

duodenum

Question 22

2 functions of myenteric (Auerbach’s) plexus

Answer 22

1. motor innervation to muscularis externa

2. secretomotor innervation to mucosa

Question 23

shortest section of small intestine

Answer 23

duodenum

Question 24

what section of the small intestine has the broadest, tallest, and most villi per unit area?

Answer 24

duodenum

Question 25

what section of the small intestine has the most goblet cells per unit area? (rank from high to low)

Answer 25

jejunum, ileum, duodenum

Question 26

what section of the small intestine has the narrowest, shortest, and sparsest villi per unit area?

Answer 26

ileum

Question 27

distinguish between small intestine and colon

Answer 27

colon has no plicae circularis or villi (has a relatively smooth surface) or Paneth cells

Question 28

distinguish between crypts of colon and small intestine

Answer 28

colon has longer crypts that are highly glandular with an abundance of goblet cells

Question 29

structure of muscularis externa of colon

Answer 29

outer longitudinal muscles are arranged in 3 distinct bands called taenia coli that cause colon to be puckered into sacculations called haustra coli

Question 30

characteristic feature of appendix

Answer 30

masses of lymphoid tissues in the mucosa and submucosa that can form follicles with germinal centers

Question 31

appendicitis symptoms

Answer 31

pain on the right side that worsens with movement

Question 32

what histological changes are seen at the recto-anal junction?

Answer 32

epithelium transitions from simple columnar to stratified squamous, crypts are replaced by large circumanal glands