GI Tract Part 2

Question 1

length of small intestine in humans

Answer 1

~4-6 m

Question 2

the small intestine in the primary site of (2)

Answer 2

absorption

digestion

Question 3

duodenum, length
jejunum length
ileum length

Answer 3

~25 cm (~1 ft)
~2 m
~3 m

Question 4

Mucosa & submucosa throughout small intestine arranged in valve-like folds/ rings,

Answer 4

plica circulares

Question 5

plica circulares

Answer 5

= valves of Kerkring

increase surface

Question 6

plica circulares contain — core

Answer 6

submucosal core

Question 7

Mucosal surface made up of —, ~1 mm long, contain core of — —

Answer 7

villi

lamina propria

Question 8

Between villi are

Answer 8

crypts of Lieberkuhn

Question 9

Coeliac disease (gluten enteropathy) causes (2)

Answer 9

villus blunting & atrophy

Question 10

Coeliac disease(gluten enteropathy) causes villus blunting & atrophy results in (2)

Answer 10

malabsorption & weight loss

Question 11

Epithelium supported by connective tissue lamina propria, containing capillaries & lymphatics for

Answer 11

absorption of nutrients

Question 12

Intestinal villi lined by

Answer 12

simple columnar epithelium

Question 13

Mucosal cells of the small intestine called —, cover surface of villi

Answer 13

enterocytes

Question 14

— surface highly folded, modified into microvilli

Answer 14

Apical/luminal

Question 15

Apical/ luminal surface highly folded, modified into microvill is also known as

Answer 15

striated or brush border

Question 16

microvilli increase surface area for

Answer 16

absorption

Question 17

microvilli are coated with protective

Answer 17

glycocalyx of disaccharides

Question 18

glycocalyx of disaccharides is a site of

Answer 18

membrane digestion

Question 19

Interspersed among enterocytes

are

Answer 19

mucus secreting goblet cells

Question 20

Interspersed among enterocytes
are mucus secreting goblet cells;
Synthesize

Answer 20

mucinogen, resulting in mucus

Question 21

mucinogen is stored in

Answer 21

membrane-bound

granules

Question 22

mucinogen (2) epithelium

Answer 22

lubricates and protects

Question 23

Actively dividing — — located

at base of crypts

Answer 23

stem cells

Question 24

Cells migrate up villus, mature, &

are —

Answer 24

shed

Question 25

Entire epithelial lining replaced in

Answer 25

3- | 5 days

Question 26

--- cells found at base of crypts

Answer 26

Paneth

Question 27

Paneth cells found at base of crypts; contain large eosinophilic granules—produce antibacterial proteins called ---, and enzymes, including ---

Answer 27

defensins | lysozyme

Question 28

Small #’s of --- cells scattered throughout

Answer 28

enteroendocrine (APUD)

Question 29

enteroendocrine cells regulate (2)

Answer 29

GI mobility and secretion

Question 30

“S” cells secrete

Answer 30

secretin (stimulate release of bicarbonate from pancreas)

Question 31

“I” cells secrete

Answer 31

cholecystekinin, or CCK (stimulates pancreatic secretion & contraction of gallbladder)

Question 32

“A” cells secrete

Answer 32

glucagon | increase blood sugar

Question 33

“K” cells secrete

Answer 33

GIP (gastric inhibitory peptide)

Question 34

MALT located in (2)

Answer 34

lamina propria & | submucosa of small intestine

Question 35

MALT contains plasma cells, which sec...

Answer 35

IgA

Question 36

Epithelium contains enlarged

Answer 36

“M” cells (microfold)

Question 37

Epithelium contains enlarged “M” cells (microfold) —squamoid enterocytes modified for (2)

Answer 37

Ag sampling, uptake of | macromolecules

Question 38

May also see --- ---, dome-shaped areas grossly visible on surface of mucosa, project into lumen

Answer 38

Peyer’s patches

Question 39

duodenum is characterized by presence of | --- --- in submucosa

Answer 39

Brunner’s glands

Question 40

Brunner’s glands contain large numbers of

Answer 40

highly convoluted, branched, tubuloalveolar submucosal glands

Question 41

Brunner’s glands secrete (2), unique to duodenum

Answer 41

mucus and zymogens

Question 42

Main function of duodenum (2), | assisted by pancreas & gallbladder

Answer 42

neutralize gastric acid & pepsin

Question 43

Pancreatic duct & bile duct empty into duodenum at

Answer 43

major duodenal papilla

Question 44

Chyme from stomach stimulates release of (2) hormones from APUD cells

Answer 44

secretin& CCK

Question 45

secretin& CCK both promote section of

Answer 45

exocrine pancreas

Question 46

Pancreatic secretions highly alkaline, due to

Answer 46

bicarbonate (neutralize stomach acid)

Question 47

CCK also stimulates contraction of gallbladder & release of

Answer 47

bile acids

Question 48

bile acids act as

Answer 48

emulsifying agents for digestion of lipids, form micelles

Question 49

Pancreatic secretions also contain proteolytic enzymes (2) for digestion of proteins (+ amylase & lipase)

Answer 49

trypsin & chymotrypsin

Question 50

Secreted as inactive precursors (zymogens),

Answer 50

trypsinogen & chymotrypsinogen

Question 51

Secreted as inactive precursors (zymogens), trypsinogen & chymotrypsinogen to prevent ---

Answer 51

autolysis

Question 52

trypsin activated by ---

Answer 52

enterokinase

Question 53

trypsin then activates ---

Answer 53

chymotrypsin

Question 54

two steps of digestion

Answer 54

luminal digestion | membrane digestion

Question 55

luminal digestion involves

Answer 55

mixing of chyme with | pancreatic enzymes

Question 56

luminal digestion results in

Answer 56

molecular breakdown

Question 57

membrane digestion involves

Answer 57

enzymes of glycocalyx on plasma membrane of enterocytes

Question 58

Enterocytes synthesize various enzymes, | 3) & produce various carrier proteins for absorption of (2

Answer 58

peptidases, peptide hydrolases, disaccharidases carbohydrates & AA’s