Small and Large Intestine

Question 1

How long are the small intestines?

Answer 1

4-6 m in humans

Question 2

What process is completed in the small intestine?

Answer 2

absorption and completion of digestion

Question 3

What are valve-like folds or rings in the small intestine?

Answer 3

plicae circulares

Question 4

What is the function of the plicae circulares?

Answer 4

increase the surface area in the small intestine

Question 5

What is on the mucosal surface of the small intestine?

Answer 5

villi

Question 6

What is the core of the villi of the mucosal surface?

Answer 6

lamina propria

Question 7

What is the space between the villi called?

Answer 7

crypts of Lieberkuhn

Question 8

What lines the intestinal epithelium?

Answer 8

simple columnar epithelium

Question 9

What is Celiac disease?

Answer 9

allergy to the wheat protein gluten (causes villus blunting, atrophy, and loss)

Question 10

What can celiac disease lead to?

Answer 10

malabsorption and weight loss (not a real symptom according to M Cole)

Question 11

What is intraepithelial lymphocytes?

Answer 11

the prescence of lymphocytes epithelial cells

Question 12

What are the three functional zones in the epithelium of the small intestine?

Answer 12

1. villi
2. crypts
3. neck (where villi and crypt meet)

Question 13

What are the five cell types of the small intestine?

Answer 13

1. enterocytes
2. mucous cells
3. paneth cells
4. endocrine cells
5. stem cells

Question 14

What are the characteristrics of enterocytes?

Answer 14

• mucosal cells
• tall columnar cells
• round/oval nuclei
• microvilli (brush border)
• protective glycocalyx coating

Question 15

What separates enterocytes from luminal surface?

Answer 15

desmosomes and tight junctions

Question 16

What do the lateral walls of enterocytes have?

Answer 16

complex interdigitations

Question 17

What are the characteristics of mucous cells in the small intestine?

Answer 17

• goblet cells
• found in upper 2/3 of crypt
• synthesize mucinogen
• least frequent in duodenum (most in ileum)

Question 18

What are the characteristics of paneth cells?

Answer 18

• found at the base of crypts
• large eosinophilic granules
• produce defensins (antibacterial proteins)
• produce lysozyme

Question 19

What are the characteristics of enteroendocrine cells?

Answer 19

• mainly in lower 1/3 of crypt
• pale-stainingcytoplasm
• broad at base and narrow at lumen
• regulate GI motility and secretion

Question 20

What are the different types of enteroendocrine cells?

Answer 20

S
I
A
K

Question 21

What do S enteroendocrine cells do?

Answer 21

secrete secretin (stimulates release of bicarb from pancreas)

Question 22

What do I enteroendocrine cells do?

Answer 22

secrete cholecystekinin/CKK (stimulates pancreatic secretion and contraction of gallbladder)

Question 23

What do A enteroendocrine cells do?

Answer 23

secrete glucagon (increases blood sugar)

Question 24

What do K enteroendocrine cells do?

Answer 24

secrete GIP (gastric inhibitory peptide)

Question 25

What are the characteristics of stem cells in the small intestine?

Answer 25

- located at base of crypt - migrate up villus, mature, and shed

Question 26

The entire epithelial lining is replaced roughly every?

Answer 26

3-5 days

Question 27

What is the lamina propria made of in small intestine?

Answer 27

collagen, reticular fibers, fibroblasts, GAGs

Question 28

Where is the lamina propria located in the small intestine?

Answer 28

clearly seen in the core of the villi but also around gland crypts

Question 29

What is a lacteal?

Answer 29

the lymphatic vessels of the small intestine which absorb digested fats (she didn't really have the definition on her slide)

Question 30

Where is MALT located in the small intestine?

Answer 30

lamina propria and submucosa

Question 31

What does MALT contain?

Answer 31

- lymphocytes (T) - plasma cells (secrete IgA) - eosinophils - macrophages - mast cells - M cells (antigen sampling) - peyer's patches

Question 32

What area of the small intestine has brunner's glands in the submucosa?

Answer 32

duodenum

Question 33

What are the characteristics of brunner's glands?

Answer 33

- highly convoluted branched, tubuloalveolar submucosal glands

Question 34

What do brunner's glands secrete?

Answer 34

- mucus (alkalin; protect against stomach acid contents) - zymogens

Question 35

What is the main function of the duodenum?

Answer 35

neutralize gastric acid and pepsin (assisted by pancreas and gallbladder)

Question 36

Where in the small intestine are peyer's patches located?

Answer 36

ileum

Question 37

What are the four cell types in the large intestine?

Answer 37

1. columnar cells 2. mucous cells 3. endocrine cells 4. stem cells

Question 38

What is the function of the large intestine?

Answer 38

- modifies fluid content of feces - specialized for mucous secretion - salt and water absorption

Question 39

What does the large intestine lack?

Answer 39

DOES NOT HAVE villi plicae circulares brunner's glands

Question 40

What is the primary function of the colon?

Answer 40

water and electrolyte resorption; produces mucus for elimination of undigested food and waste

Question 41

What are the characteristics of the columnar cells of the large instestine?

Answer 41

- mainly columnar with little mucin - absorb soluble satl and water

Question 42

What are the characteristics of the mucous cells of the large instestine?

Answer 42

- goblet cells - present throughout the colon but the type of mucus can change

Question 43

How does MALT appear in the large intestine?

Answer 43

- does not form peyer's patches

Question 44

Are there lacteals in the small intestine or large intestine?

Answer 44

only small

Question 45

What are some characteristics of the colon?

Answer 45

- large # of commensal bacteria - outer longitudinal muscle layer is incomplete (forms 3 longitudinal strips, taenia coli) - formation of haustra

Question 46

What is the small, blind-ended sac that is distal to the ielo-cecal junciton?

Answer 46

appendix

Question 47

What is the function of the appendix?

Answer 47

- vestigial cecum - used for bacterial digestion in herbivores - contains a large amount of MALT and is more active in children

Question 48

What is a polyp (adenoma) in the GI?

Answer 48

any mass arising from the wall of the colon that protrudes into the lumen

Question 49

What is treatment for colon cancer (adenocarcinoma)?

Answer 49

surgical removal

Question 50

What decreases the risk of colon cancer?

Answer 50

increase in roughage and fiber in the diet (decrease transit time and increase GI motility)

Question 51

How can you prevent/catch colon cancer?

Answer 51

New test kits for early detection; detect tumor Ab; also colonoscopy screening over 50

Question 52

What are the characteristics of the rectum?

Answer 52

- contains transverse rectal folds and mucus glands - simple columnar epithelium

Question 53

What does the epithelium transition to in rectum to the anus?

Answer 53

simple columnar epithelium (rectum) stratified squamous epithelium (anal canal)

Question 54

What are the characteristics of the anal canal?

Answer 54

- stratified squamous epithelium - longitudinal folds called anal columns - anal glands (extend into submucosa and muscularis externa) - external opening; exit of GI

Question 55

What are the internal and external anal sphincters made of?

Answer 55

surrounded by muscle - external = voluntary, skeletal M - internal = involunary, smooth M

Question 56

What does occasional enlargment and irritaion of submucosal veins in the anal canal lead to?

Answer 56

hemorrhoids (varicose veins)

Question 57

Where can hemorrhoids of the GI develop?

Answer 57

inside the rectum (internal hemorrhoids) or under the skin around the anus (external hemorrhoids)

Question 58

Where is the referred pain with internal hemorrhoids?

Answer 58

follows autonomics, diffuse

Question 59

Where is the referred pain with external hemorrhoids?

Answer 59

somatic pain, sharp and well-localized