Motility of the GI Tract

Question 1

cell type that produces the hydrochloric acid and intrinsic factor in the stomach

Answer 1

parietal cell

Question 2

cell type that produces pepsinogen in the gastric pits of the stomach

Answer 2

chief cell

Question 3

cell type that produces gastrin in the stomach

Answer 3

enteroendocrine cell

Question 4

pacemaker cells that have the capacity to generate the basic electrical rhythm of GI smooth muscle

Answer 4

Interstitial cells of cajal

Question 5

the ICCs utilize what type of channel to induce contraction in smooth muscle

Answer 5

L type Ca current and AP mechanism

Question 6

oscillating waves of membrane depolarization that are not sufficient to completely depolarize the membrane and stimulate contractions in the GI tract

Answer 6

Slow waves or the basic electrical rhythm

Question 7

slow, oscillating changes in membrane potential that do not induce contraction utilize which ion

Answer 7

Na

Question 8

spike potentials that cause contractions are a result of which ion moving across membranes

Answer 8

Ca

Question 9

functions of the myenteric plexus

Answer 9

control function of circular and longitudinal muscle layers to control GI movements

Question 10

functions of submucosal plexus

Answer 10

secretomotor neurons promote vasodilation, regulate secretion of fluid and electrolytes and contractions of the muscularis mucosa

Question 11

components of saliva

Answer 11

water
electrolytes
Mucin 
IgA 
Lysozyme 
salivary amylase

Question 12

three phases of swallowing

Answer 12

oral phase
pharyngeal phase
esophageal phase

Question 13

difference between primary and secondary peristaltic waves

Answer 13

primary - continuation of the peristaltic wave that begins in the pharynx and spreads into esophagus (regulated by medulla)
Secondary - occurs if primary wave fails to move food all the way to stomach. Continues until food empties into stomach (regulated by medulla and myenteric nervous system)

Question 14

describe receptive relaxation

Answer 14

vagovagal reflex that causes the muscles of the proximal stomach to relax, which facilitates entry of the bolus into the stomach
esophageal pressure drops to match low pressure in proximal stomach, indicating opening of the LES
LES opens due to vagovagal reflex mediated by myenteric neurons releasing vasoactive intestinal peptides and NO

Question 15

LES tone can be ______ by acetylcholine, increased intraabdominal and intragastric pressure, gastrin, motilin, protein-rich food

Answer 15

increased LES tone

Question 16

LES tone can be _____ by NO, VIP, CCK, GIP, Beta adrenergic receptor antagonists, secretin, progesterone, prostaglandin E and fat rich food

Answer 16

Decreased LES tone

Question 17

MoA of Gerd

Answer 17

innappropriate relaxation of LES results in reflux of acidic stomach contents sufficient to cause pain or erosion

Question 18

MoA of achalasia

Answer 18

LES does not open fully in concert with the peristaltic wave that sweeps the bolus along the length of the esophagus and food becomes retained at LES
Disordered motility from degeneration of neurons in the myenteric plexus

Question 19

factors that increase contraction in the stomach

Answer 19

vagal nerve (parasympathetic sitmulation) - force and number 
gastrin and motilin - increase contractions

Question 20

increases gastric H+ secretion and stimulates growth of gastric mucosa

Answer 20

Gastrin from G cells of stomach

Question 21

stimulates contraction of gallbladder and relaxation of sphincter of Oddi
increase pancreatic enzyme and HCO3 secretion
growth of exocrine pancreas and gallbaldder

Answer 21

CCK

Question 22

increase pancreatic HCO3 secretion
increase biliary HCO3 secretion
Decrease gastric H secretion

Answer 22

secretin

Question 23

increase insulin secretion

decrease gastric H secretion

Answer 23

GIP

Question 24

when gastrin is secreted by non-Beta cell tumors of the pancreas

Answer 24

zollinger-ellison syndrome

Question 25

gastrin secretion is stimulated by

Answer 25

small peptides and AA in the lumen (Phe and Trp) distension of stomach vagal stimulation by GRP (gastrin releasing peptide)

Question 26

gastrin secretion is inhibited by

Answer 26

H+ in the lumen of the stomach (negative feedback) | somatostatin

Question 27

a collection of disorders of various etiologies in which gastric emptying is impaired or delayed, without evidence of obstruction really common in diabetes

Answer 27

gastroparesis

Question 28

movements in the small intestine (2)

Answer 28

peristalsis and segmentation contractions