GI III

Question 1

Describe the epithelium of small intestines

Answer 1

mainly absorptive columnar cells with well-developed brush borders

Question 2

What type of lymphocytes are located in the mucosa of the small intestines?

Answer 2

intraepithelial lymphocytes (T cells)

Question 3

Loose connective tissue that extends into the villi

Answer 3

Lamina propria of the small intestines

Question 4

What are lacteals?

Answer 4

well endowed with blood and lymphatic vessels (within the lamina propria)

Question 5

Where are goblet cells found in the small intestines?

Answer 5

their numbers increase as the ileum is approached

Question 6

What is another name of intestinal glands found in lamina propria of the small intestines?

Answer 6

crypts of Lieberkuhn

Question 7

What type of epithelium does crypts of Lieberkuhn have?

Answer 7

simple columnar

Question 8

What are the three different cell types of the intestinal glands?

Answer 8

1) paneth cells
2) enteroendocrine cells
3) stem cells

Question 9

What’s the function of paneth cells?

Answer 9

secrete lysozyme, defensins, and tumor necrosis factor alpha

Question 10

Paneth cells extend into which structure?

Answer 10

right colon

Question 11

Where are the stem cell niche located?

Answer 11

at the base of the gland (different than the stomach)

Question 12

Where does enteroendocrine cells secrete their products, toward the lumen or tissues?

Answer 12

Toward the tissues NOT the lumen

Question 13

Which segment is the shortest of small intestines?

Answer 13

duodenum

Question 14

Which layer are the glands located in the duodenum?

Answer 14

submucosa

Question 15

Which gland is a signature feature of the duodenum?

Answer 15

Brunner’s glands

Question 16

What’s the function of Brunner’s glands?

Answer 16

secrete mucus and human epidermal growth factor

Question 17

Which part of the duodenum are Brunner’s glands most developed?

Answer 17

proximal

Question 18

Which has a thicker wall, jejunum or ileum?

Answer 18

jejunum

Question 19

Which is more richly vascularized, jejunum or ileum?

Answer 19

jejunum (redder than ileun)

Question 20

Which part of the small intestines are Peyer’s patches located?

Answer 20

ileum

Question 21

Which part of the small intestines will you find M cells?

Answer 21

Peyer’s patches of the ileum and lymphoid tissues of gut as well

Question 22

Instead of plicae circulares, what does the large intestines have?

Answer 22

plicae semilunares - permanent folds of mucosa and submucosa

Question 23

Does the large intestines have villi?

Answer 23

NO

Question 24

Does the large intestines have brush border?

Answer 24

Yes, but it’s poorly developed

Question 25

True or False. Goblet cells are more numerous in the small intestine than the large intestine

Answer 25

False, it's the other way around

Question 26

Does the crypt density increase or decrease in large intestine? What about goblet cell density?

Answer 26

Both increase

Question 27

Why is paucity of lymphatic channels significant?

Answer 27

an intramucosal carcinoma has little or no potential to metastasize

Question 28

In which direction does the lymphatics of large intestine extend, radially or longitudinally?

Answer 28

radially

Question 29

Which smooth muscle layer does not completely surround the large intestine?

Answer 29

outer longitudinal

Question 30

What is teniae coli?

Answer 30

three longitudinal bands of smooth muscle found in the muscularis externa

Question 31

Appendix - mucosa resembles ____ while submucosa resembles ____

Answer 31

mucosa - large intestine | submucosa - small intestine

Question 32

The appendix has lack of which two structures?

Answer 32

teniae coli and villi

Question 33

What are two mechanisms of appendicitis?

Answer 33

1) fecalith and intraluminal pressure | 2) infection and mucosal ulceration

Question 34

What's the name of the three permanent folds found in the rectum?

Answer 34

transverse rectal folds or valves of Houston

Question 35

Valve of Houston is a permanent fold of which layers?

Answer 35

1) mucosa 2) submucosa 3) portions of muscularis externa

Question 36

What are anal columns?

Answer 36

longitudinal folds of submucosa and mucosa

Question 37

What is the significance of the pectinate line?

Answer 37

lymphatics drain differently above an below this line due to derivation.

Question 38

Superior to pectinate line, which layer contains plexus of veins?

Answer 38

submucosa

Question 39

Inferior to pectinate line, which layer contains plexus of veins?

Answer 39

lamina propria

Question 40

What are the three anal cushions?

Answer 40

1) left lateral (3 o'clock) 2) right anterior (7 o'clock) 3) right posterior (11 o'clock)

Question 41

What are anal cushions composed of?

Answer 41

connective tissue, smooth muscle, and blood vessels

Question 42

What's the function of anal cushions?

Answer 42

anal continence

Question 43

Where are anal valves located?

Answer 43

between distal adjacent anal columns

Question 44

Where are anal sinuses located?

Answer 44

lateral to the valves

Question 45

What type epithelium will you find below the pectinate line?

Answer 45

Stratified squamous

Question 46

What divides non-keratinized epithelium versus keratinized epithelium in the anal canal?

Answer 46

intersphinctic groove

Question 47

Will you feel pain if you had hemorrhoids above the dentate (pectinate) line?

Answer 47

no

Question 48

Will you feel pain if you had hemorrhoids below the dentate (pectinate) line?

Answer 48

yes

Question 49

What are anorectal abscess?

Answer 49

gland secretions and/or fecal matter can plug up anal sinuses, causing inflammation and infection. pus then accumulates

Question 50

What is fistula in ano?

Answer 50

anorectal abscesses that develop into tubes that penetrate skin of the perineum, connecting the anal canal with it

Question 51

What is colonic diverticula?

Answer 51

outpouching of the diverticula (large intestine), sites of weakness between tenia coli

Question 52

Why is it called false diverticula?

Answer 52

because it involves mucosa and submucosa

Question 53

What layers are affected in true diverticula?

Answer 53

all wall layers

Question 54

What are polyps?

Answer 54

hyperproliferative cells that start to pile up on luminal surface

Question 55

Which is more likely to be invasive, tubular adenoma or villous adenoma?

Answer 55

villous adenoma is more likely to be invasive

Question 56

Does the lamina propria of the large intestine have well endowed lymphatic vessels?

Answer 56

No

Question 57

In the presence of inflammatory bowel disease, is lamina propria better or poorly developed?

Answer 57

better developed

Question 58

Which inflammatory bowel disease is typically confined to large intestine?

Answer 58

ulcerative colitis

Question 59

Which inflammatory bowel disease can be found anywhere along the GI tract?

Answer 59

Crohn's disease

Question 60

Which inflammatory bowel disease is more likely to cause fissures or fistulas?

Answer 60

Crohn's disease

Question 61

What occurs in Hirschsprung's disease?

Answer 61

neural crest cells do not make proper migration to the involved segment of colon

Question 62

Hirschsprung's disease always involves...

Answer 62

rectum and may also more proximal segments

Question 63

What is aganlionosis?

Answer 63

both myenteric and submucosal plexuses are absent