9/19/22

Question 1

mucus

Answer 1

composed of mucin, H2O, and bicarbonate (HCO3-), lubricates foods and protects mucosa (against super acids)

protects stomach w/ protein and water

Question 2

intrinsic factor

Answer 2

needed for vitamin B12 absorption

Question 3

enzymes

Answer 3

pepsin; gastric lipase

Question 4

hydrochloric acid (HCl)

Answer 4

facilitates digestion, protein degradation, and absorption of micronutrients

Question 5

oxyntic gland

Answer 5

located in body and fundus
secretion: HCl, pepsinogen, intrinsic factor, histamine, somatostatin

Question 6

pyloric gland

Answer 6

located in pyloric antrum (near pylorus, entry to duodenum)
secretion: mainly mucus. Also gastrin and somatostatin

Question 7

parietal cell

Answer 7

secretes HCl, intrinsic factor

Question 8

enterochromatin-like cell

Answer 8

secretes histamine (allergens, inflammation)

Question 9

D cell

Answer 9

secretes somatostatin

Question 10

chief cells

Answer 10

secrete pepsinogen

Question 11

pepsinogen

Answer 11

a zymogen (inactive protease)
if not a zymogen, would digest everything
turned into pepsin (active form) in stomach lumen in response to H+

Question 12

proteases role

Answer 12

break peptide bonds

Question 13

gastric acid pH

Answer 13

2
same as lemon juice

Question 14

gastric acid aka

Answer 14

HCl

Question 15

gastric acid functions

Answer 15

1. converting or activating pepsinogen to form pepsin
2. denaturing proteins
3. releasing various nutrients such as vitamins and minerals from organic complexes so absorption can occur
4. acting as a bactericide agent (needed to kill bacteria ingested with food
5. contains mucins

Question 16

mucins

Answer 16

bind water and form gel: provide lubrication and protection

Question 17

no parietal cells would lead to

Answer 17

no intrinsic factor, no vitamin B12 absorption

Question 18

parietal cell purpose

Answer 18

regulate acid secretion

Question 19

parietal cell phases

Answer 19

1. Cephalic
2. Gastric
3. Intestinal

Question 20

cephalic phase of acid secretion

Answer 20

1. think/smell/see food
2. release ACh which sends signal to stomach to release Gastrin

Question 21

gastric phase of acid secretion

Answer 21

1. stretching of stomach signals release of Gastrin

Question 22

intestinal phase of acid secretion

Answer 22

SST inhibits HCl
Secretin activates bicarbonate release

Question 23

chief cells secretions

Answer 23

pepsinogens I and II are secreted in granules into the gastric lumen by chief cells
main stimuli for secretion: acetylcholine, HCl, low pH

Question 24

pepsin role

Answer 24

chops proteins into aa

Question 25

GERD mechanism

Answer 25

increase pressure in stomach opens lower vasovagal sphincter esophagus pH is typically 7 but lowers to around 2 with GERD

Question 26

GERD causal factors

Answer 26

carminatives (spearmint, peppermint) fatty foods alcohol smoking

Question 27

GERD pathway

Answer 27

1. GERD 2. Heartburn 3. Esophagitis 4. Ulcer

Question 28

GERD treatments

Answer 28

1. smaller meals 2. higher protein 3. dairy 4. antiacids 5. fluid between meals 6. avoid causal factors

Question 29

ACh pathway

Answer 29

1. ACh causes gastrin release 2. gastrin enters circulation and goes to bile cell 3. acid release in stomach

Question 30

cause of stomach peptic ulcer

Answer 30

disruption of mucosa (very pH sensitive) of GI tract

Question 31

peptic ulcer causal factors

Answer 31

1. gastric acid 2. pepsin 3. H. pylori (normal stomach bacteria) 4. chronic uses of aspirin, alcohol, NSAIDs (ibuprofen)

Question 32

peptic ulcer treatments

Answer 32

1. diet 2. H2 receptor blockers (cimetidine, ranitidine) 3. PPIs (omeprazole, esomeprazole)

Question 33

no gut microbiota =

Answer 33

no immune system

Question 34

gut microbiota functions

Answer 34

1. maturation and education of host immune response 2. protection against pathogen overgrowth 3. influence host-cell proliferation and vascularization (create new and repair old blood vessels) 4. regulate intestinal endocrine functions 5. source of energy biogenesis (5-10% of daily host energy requirements

Question 35

other gut microbiota functions

Answer 35

1. neurologic signaling and bone density 2. biosynthesis of vitamins, NTs, and other bioactive compounds 3. metabolism of bile salts, drugs and elimination of exogenous toxins

Question 36

microbial composition in GI tract

Answer 36

>1000 different species, largely bacteria 1. bacteria 2. archaea 3. viruses 4. fungi/yeast 5. protozoa

Question 37

2 main phyla of gut bacteria

Answer 37

firmicutes bacteriodetes make up 90% of gut bacteria

Question 38

effects of maternal exposure on microbiome

Answer 38

environment antisepsis antibiotics diet

Question 39

vertical transmission in early life of microbiome

Answer 39

1. oral (pre-mastication of food) 2. mammary (through brestfeeding, selection) 3. cutaneous (contact with skin) 4. vaginal (passage through birth canal

Question 40

where do most bacteria live in the body?

Answer 40

the colon! why? train immune system, breakdown food