GI

Question 1

What are the major functions of the GI system

Answer 1

Transport food
Digestion
Absorption of nutrients

Question 2

After mastication, what is the motility of the different GI segments?

Answer 2

Deglutition

Question 3

What are the functions of the GI tract movements?

Answer 3

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 4

What is the voluntary phases of deglutition?

Answer 4

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

Question 5

What occurs during the involuntary phase of deglutition?

Answer 5

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 6

How is food moved through the esophagus during deglutition?

Answer 6

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

Peristaltic movements

Question 7

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

Answer 7

Aspiration

Question 8

What is disphagia ?

Answer 8

Difficulty swallowing

Orapharyngeal or esophageal

Question 9

What is the regulatory center for energy homeostasis?

Answer 9

Hypothalamus

Question 10

What neuropeptide of the hypothalamus stimulates hunger?

Answer 10

Neuropeptide Y (NPY) and orexin

Question 11

What neuropeptide of the hypothalamus inhibits hunger?

Answer 11

Melanocyte-stimulating hormone

Question 12

What non-hypothalamic hormone stimulates hunger?

Answer 12

Ghrelin

Question 13

What non-hypothalamic hormone inhibits hunger?

Answer 13

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

Question 14

What are the primary functions of saliva?

Answer 14

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

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

Question 15

What is primary saliva ?

Answer 15

Cl-, Na+, H2O (basolateral transporters)

Question 16

What is secondary saliva?

Answer 16

K+ and HCO3- (apical transporters)

Question 17

How is saliva secretion regulated by the PSNS and SNS?

Answer 17

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

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

(Innate or conditioned response)

Question 18

What are the two types of salivary glands of ruminants?

Answer 18

Isotonic and hypotonic to plasma

Question 19

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

Answer 19

Endocrine
Paracrine
Autocrine
Neurocrine

Question 20

What are the characterisitics of a GI hormone?

Answer 20

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 21

What hormone is synthesized in the antrum and duodenum?

Answer 21

Gastrin

Question 22

Where are GIP and Motilin synthesized?

Answer 22

Duodenum and jejunum

Question 23

Where is CCK synthesized?

Answer 23

Duodenum, jejunum, and ileum

Question 24

Secretin stimulates ___________ secretion and inhibits _________ secretion

Answer 24

Bicarbonate ; acid

Question 25

Gastrin stimulates __________ secretions

Answer 25

Acid

Question 26

Gastric inhibitory polypeptide inhibits__________________ secretion and stimulates ______ secretion

Answer 26

Gastric; insulin

Question 27

What is the action of motilin?

Answer 27

Induction of intestinal motility during fasting

Question 28

What are the three glandular zones of the stomach?

Answer 28

Cardias Fundus Pylorus

Question 29

What are the 5 cell types found in the stomach?

Answer 29

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

Question 30

Parietal cells produce?

Answer 30

HCl

Question 31

What do chief cells produce?

Answer 31

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

Question 32

Enteroendocrine cells produce?

Answer 32

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

Question 33

What cells types of the stomach produce mucus?

Answer 33

Mucous producing cells

Question 34

What is the function of mucus in the stomach?

Answer 34

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

Question 35

What three hormones induce production of HCl?

Answer 35

Gastrin Histamin ACh

Question 36

What stimulates Gastrin release from G cells?

Answer 36

Gastrin releasing hormone | Food

Question 37

What inhibits gastrin secretion by G cells

Answer 37

Somatostatin (from D cells)

Question 38

How does ACh, histamin, and gastrin induce HCl secretion

Answer 38

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 39

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

Answer 39

Somatostatin; gastrin secretion from G cells

Question 40

Enzymatic secretion by chief cells is regulated by ?

Answer 40

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

Question 41

NSAIDs can produce ulcers by inhibiting __________

Answer 41

COX enzymes

Question 42

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

Answer 42

Gastric ulcer

Question 43

Gastric ulcers can be caused by?

Answer 43

Bacteria eg. H.pylori | NSAID