GI, USMLE

Question 1

Portions of GIT composed of striated instead of smooth muscle (3)

Answer 1

1) Pharynx
2) Upper 1/3 of esophagus
3) External anal sphincter

Question 2

Sites of phasic contractions in GIT (3)

Answer 2

1) Esophagus
2) Gastric antrum
3) Small intestine

Question 3

Sites of tonic contractions in GIT

Answer 3

1) Sphincters

2) Orad stomach

Question 4

Stimulus for involuntary swallowing reflex in the swallowing center

Answer 4

Food bolus in the pharynx

Question 5

Phase of swallowing wherein breathing is inhibited

Answer 5

Pharyngeal phase

Question 6

Only phase of swallowing that is voluntary

Answer 6

Oral

Question 7

Periods of small intestinal contractions that occur during the fasting state

Answer 7

Migrating myoelectric complexes

Question 8

Type of large intestinal contraction that mix intestinal contents

Answer 8

Segmentation contraction

Question 9

Segmentation contraction: Segments of LI

Answer 9

1) Cecum

2) Proximal colon

Question 10

Proximal vs distal colon: Water absorption

Answer 10

Distal

Question 11

There is an urge to defecate once rectum fills to ___% of capacity

Answer 11

25%

Question 12

Purpose of salivary HCO3

Answer 12

Maintains dental health by neutralising oral bacterial acids

Question 13

Acinar vs ductal cells of salivary glands: Secreter IgA

Answer 13

Acinar

Question 14

Sympathetic input to salivary glands originate from

Answer 14

T1-T3, synapse at superior cervical ganglion

Question 15

PSY input to salivary glands originate from

Answer 15

CN VII and IX

Question 16

Runs through the parotid gland and may be damaged during surgery

Answer 16

CN VII

Question 17

Openings of gastric gland ducts

Answer 17

Gastric pits

Question 18

T/F G cells secrete gastrin into systemic circulation, not pyloric ducts

Answer 18

T

Question 19

T/F Mucosal neck cells secrete mucus and HCO3 into pyloric ducts

Answer 19

T

Question 20

Parietal cell polarity: Channels on apical membrane

Answer 20

1) H-K ATPase

2) Cl- channels

Question 21

Parietal cell polarity: Channels on basolateral membrane

Answer 21

1) Na-K ATPase pump

2) Cl-HCO3 exchanger

Question 22

Responsible for alkaline tide observed in gastric venous blood following a meal

Answer 22

HCO3- from intestinal cell via Cl-/HCO3- exchanger