Exam 5 GI

Question 1

Gastrin
location?
function?

Answer 1

stomach (G cells)
gastric acid secretion & gastric motility & stimulates pancreas to release digestive enzymes

Question 2

CCK
location?
function?

Answer 2

small intestine duodenal cells
secretion of pancreatic digestive enzymes, secretion of bile, satiety, and control gastric motility (inhibits gastric activity)

Question 3

Secretin
location?
function?

Answer 3

small intestine epithelium
secretion of bicarb and water & helps inhibit gastric activity

Question 4

Ghrelin
location?
function?

Answer 4

stomach (gastric epithelial cells)
appetite stimulation and promotes fat storage

Question 5

leptin
location?
function?

Answer 5

adipocytes
decrease appetite, satiety

Question 6

motilin
location?
function?

Answer 6

small intestine epitheial cells
controls smooth m contraction/ responsible for migrating motor complex

Question 7

glucagon
location?
function?

Answer 7

pancreas
increased blood glucose levels

Question 8

insulin
location?
function?

Answer 8

pancreas
control blood glucose levels (decreases) & stimulates storage of excess sugar & also modulates fat storage for hibernators

Question 9

aldosterone
location?
function?

Answer 9

adrenal glands
sodium and water reabsorption

Question 10

proenzymes/zymogens

Answer 10

inactive enzymes

Question 11

pepsinogen
location?
function?

Answer 11

chief cells in stomach
protein breakdown

Question 12

trypsinogen
location?
function?

Answer 12

pancreatic exocrine cells
activated by enterokinase to activate chymotrypsinogen –> chymotrypsin & protein digestion

Question 13

chymotrypsinogen
location?
function?

Answer 13

pancreatic exocrine cells
activated by trypsin for protein digestion

Question 14

lipase
location?
function?

Answer 14

pancreatic exocrine cells
hydrolyzes triglycerides –> free fatty acids + glycerol
requires bile acids

Question 15

amylase
location?
function?

Answer 15

pancreatic exocrine cells
hydrolyzes starch –> glucose

Question 16

adenylyl cyclase
location?
function?

Answer 16

enterocytes
activates CFTR which increases Cl- in the lumen

Question 17

brush border hydrolyases

Answer 17

enzymes that break down carbohydrates into simple sugars

Question 18

lysosyme
location?
function?

Answer 18

glandular epithelium of abomasum
breaks down bacterial cell walls

Question 19

cellulase
location?
function?

Answer 19

microbes in GI tract
break down cellulose –> glucose

Question 20

submucosal plexus

Answer 20

senses environment within the lumen, regulates GI blood flow and controls epithelial cell function
sensory normals (respond to chemical, thermal, osmotic, mech. stimuli)

Question 21

myenteric plexus

Answer 21

controls digestive tract motility
motor neurons

Question 22

what nerve is important for feeding behavior

Answer 22

vagus n.

Question 23

what prevents the esophagus from trauma

Answer 23

stratified squamous epithelium

Question 24

gastroesophageal reflux disease (GERD)

Answer 24

improper closing of lower sphincter

Question 25

megaesophagus

Answer 25

dilation/loss of motility of esophagus

Question 26

surfous mucous/mucous neck cells

Answer 26

mucus to protect epithelium

Question 27

parietal cells

Answer 27

HCl

Question 28

chief cells

Answer 28

pepsinogen

Question 29

endocrine cells of the stomach

Answer 29

gastrin

Question 30

gastic motility in upper stomach vs lower

Answer 30

upper = low frequency of sustained contractions to maintain basal pressure and gastric emptying
lower = strong peristaltic waves of contraction (gastric grinding)

Question 31

four phases of the migrating motor complex

Answer 31

quiescence
peristaltic contractions
rapid contractions
short transition period

Question 32

what is the enterogastric reflex

Answer 32

slowing down of the small intestine
SI releases CCK/secretin to suppress gastric activity

Question 33

intrinsic barrier vs extrinsic barrier

Answer 33

intrinsic = epithelial cells line digestive tube & tight junctions & cell turnover
extrinsic = maintains epithelial cells, mucus, bicarb. etc.

Question 34

disruptions of the barriers

Answer 34

stress
ischemic reperfusion injury
infectious agents

Question 35

what controls vomitting

Answer 35

vomination centers in the medulla with chemoreceptor trigger zones
visceral afferents from GI tract (e.g. distension)
visercal afferents from outside GI tract (e.g. bile)
afferents from extramedullary centers in brain (e.g. odors, fear)

Question 36

mechanisms that protect pancreas from autodigestion

Answer 36

1. proenzymes/zymogens
2. bicarb/water

Question 37

portal triad

Answer 37

hepatic a.
portal v.
bile duct

Question 38

intrahepatic biliary system vs extrahepatic

Answer 38

intra has canaliculi and extra has series of channels/ducts (e.g. common bile duct)

Question 39

metabolic fate of heme and formation of bilirubin

Answer 39

heme eliminated by conversion to bilirubin which is conjugated and secreted into SI where it is metabolized by gut bacteria and eliminated
gives feces brown color

Question 40

villi components vs crypt

Answer 40

villi has enterocytes and goblet cells
crypts have stem cells and secretory epitheial cells

Question 41

2 processes of microbial flora

Answer 41

digestion/metabolism of cellulose and excess starch

synthesis of vitamin K, B and VFAs

Question 42

cranial fermenters vs caudal fermenters

Answer 42

cranial: starch/carbs fermented into VFAs in stomach, protein is utilized
caudal: do not utilize protein, directly utilize hexose

Question 43

importance of ruminal bacteria

Answer 43

major source of protein, synthesize proteins and vitamins, metabolize VFAs, and enzymes to digest cellulose

Question 44

VFAs

Answer 44

major fuel source for energy
acetic acid, propionic acid, butyric acid

Question 45

frothy bloat vs free gas bloat

Answer 45

frothy due to diet
free gas due to not able to eructate