GI

Question 1

What are the major functions of the GI system

Answer 1

Transport food
Digestion
Absorption of nutrients

Question 2

NSAIDs can produce ulcers by inhibiting __________

Answer 2

COX enzymes

Question 3

What inhibits gastrin secretion by G cells

Answer 3

Somatostatin (from D cells)

Question 4

How is saliva secretion regulated by the PSNS and SNS?

Answer 4

PSNS -> M3-receptors -> contraction of myoepithelial cells

SNS -> a1-receptors -> secretion of small volumes of mucous saliva

(Innate or conditioned response)

Question 5

What are the two types of salivary glands of ruminants?

Answer 5

Isotonic and hypotonic to plasma

Question 6

What is secondary saliva?

Answer 6

K+ and HCO3- (apical transporters)

Question 7

What neuropeptide of the hypothalamus inhibits hunger?

Answer 7

Melanocyte-stimulating hormone

Question 8

What occurs during the involuntary phase of deglutition?

Answer 8

In pharynx and esophagus

Breathing stops momentarily -> soft palate is elevated (close off nasopharynx) -> tongue depressed against the hard palate (close oral opening) -> bend epiglottis to block laryngeal opening -> muscular constriction to move bolus into esophagus

Question 9

What stimulates Gastrin release from G cells?

Answer 9

Gastrin releasing hormone

Food

Question 10

What are the characterisitics of a GI hormone?

Answer 10

Secreted by one cell to affect another
Transported in the blood
Stimulated by food and its action must be mimicked by a synthetic analog molecule ?

Question 11

What cells types of the stomach produce mucus?

Answer 11

Mucous producing cells

Question 12

What are the four different routes by which secretions of GI tissue can reach their target cells?

Answer 12

Endocrine
Paracrine
Autocrine
Neurocrine

Question 13

Gastric acid is regulated by low PH inducing _________ from D cells which inhibits ____________

Answer 13

Somatostatin; gastrin secretion from G cells

Question 14

What is disphagia ?

Answer 14

Difficulty swallowing

Orapharyngeal or esophageal

Question 15

What non-hypothalamic hormone inhibits hunger?

Answer 15

Cholecystokinin (CCK)
Peptide YY (PYY)
Lectin (fat cells-> inhibits NPY release and stimulate MSH action)
Insulin

Question 16

A condition in which food particles/fluids or stomach contents reach the upper airways

Answer 16

Aspiration

Question 17

What is the function of mucus in the stomach?

Answer 17

Glycoproteins with many cystine residues -> form disulfide bridges -> protect and lubricate the mucosa

Question 18

What is the action of motilin?

Answer 18

Induction of intestinal motility during fasting

Question 19

What is the regulatory center for energy homeostasis?

Answer 19

Hypothalamus

Question 20

What are the primary functions of saliva?

Answer 20

Protect buccal mucosa and teeth
Facilitate deglutition
Enzymatic carbohydrate digestion
PH regulation (HCO3-)

Secondary functions:
Immunologic -IgA
Thermoregulation (evaporation)
Defense in some species

Question 21

What are the three glandular zones of the stomach?

Answer 21

Cardias
Fundus
Pylorus

Question 22

What neuropeptide of the hypothalamus stimulates hunger?

Answer 22

Neuropeptide Y (NPY) and orexin

Question 23

How does ACh, histamin, and gastrin induce HCl secretion

Answer 23

ACh -> M3 receptors on parietal cells -> DAG and IP3 activation -> release of Ca from ER and phosphorylation of protein

• > transporters inserted into membrane
• > stimulation of H+, K+, and ATPase

Question 24

What is the voluntary phases of deglutition?

Answer 24

Food is molded into bolus and pushed back into the pharynx -> activation of sensory nerve endings -> initiate involuntary portion of deglutition

Question 25

What three hormones induce production of HCl?

Answer 25

Gastrin Histamin ACh

Question 26

Enzymatic secretion by chief cells is regulated by ?

Answer 26

ACh CCK Secretin -> DAG and IP3 -> release of Ca2+ from ER and phosphorylation of protein -> increased exocytosis from vesicles

Question 27

What hormone is synthesized in the antrum and duodenum?

Answer 27

Gastrin

Question 28

What do chief cells produce?

Answer 28

Pepsinogen ->pepsin Prochymosine -> chymosine (calves and lambs)

Question 29

How is food moved through the esophagus during deglutition?

Answer 29

Food reaches esophagus -> upper esophageal sphincter relaxes to accept the bolus -> thoracal part of esophagus contracts while lower spinsters relax Peristaltic movements

Question 30

Gastric inhibitory polypeptide inhibits__________________ secretion and stimulates ______ secretion

Answer 30

Gastric; insulin

Question 31

Gastrin stimulates __________ secretions

Answer 31

Acid

Question 32

Parietal cells produce?

Answer 32

HCl

Question 33

Secretin stimulates ___________ secretion and inhibits _________ secretion

Answer 33

Bicarbonate ; acid

Question 34

What non-hypothalamic hormone stimulates hunger?

Answer 34

Ghrelin

Question 35

Gastric ulcers can be caused by?

Answer 35

Bacteria eg. H.pylori | NSAID

Question 36

What are the functions of the GI tract movements?

Answer 36

Move ingesta Retain ingesta at a given site for digestion/absorption/storage Break up and mix food Circulate ingesta to come in contact with all absorptive surfaces

Question 37

Epithelial damage to the mucosa of the stomach is called a __________

Answer 37

Gastric ulcer

Question 38

What is primary saliva ?

Answer 38

Cl-, Na+, H2O (basolateral transporters)

Question 39

Where is CCK synthesized?

Answer 39

Duodenum, jejunum, and ileum

Question 40

What are the 5 cell types found in the stomach?

Answer 40

``` Surface mucous cells Parietal cells Mucous neck cells Enterochromaffine cell Chief cells ```

Question 41

Enteroendocrine cells produce?

Answer 41

hormones G cells -> gastrin D cells -> somatostatin I cells -> CCK

Question 42

Where are GIP and Motilin synthesized?

Answer 42

Duodenum and jejunum