GI motility

Question 1

Mastication

Answer 1

Mandibles move in all planes and also rotate.

Question 2

Functions of mastication

Answer 2

1) Reduction in particle size
2) Mixing food with saliva
3) Enhance stimulation of taste buds and other receptors.

Question 3

Mixing food with saliva _____ the mass

Answer 3

Lubricates

Question 4

Salivary amylases are responsible for _____

Answer 4

Carbohydrate digestion

Question 5

Lingual Lipases are responsible for _____

Answer 5

Lipid digestion

Question 6

Control of Mastication is

Answer 6

Reflexive. However, voluntary control can occur

Question 7

Swallowing

Answer 7

moving food and liquid from the mouth into the stomach

Question 8

_____ afferent, _____ medullary centers, and ____ efferents are involved in organizing swallowing.

Answer 8

9 afferents, 9 medullary centers and 30 efferents

Question 9

When not swallowing, upper esophageal sphincter and lower esophageal sphincter are _____

Answer 9

Contracted

Question 10

What are the three phases of swallowing?

Answer 10

Oral, pharyngeal, and esophageal

Question 11

Bolus is moved to the back of the mouth by

Answer 11

elevating the front of the tongue against the surface of the hard palate

Question 12

Bolus is moved into the oropharynx by

Answer 12

retraction and depression of the tongue

Question 13

Driving force of the oral phase

Answer 13

pressure gradient of 4-10 mm Hg

Question 14

Oral phase is under ____ control

Answer 14

Voluntary

Question 15

Pharyngeal phase is an _____ reflex coupled to the _____

Answer 15

involuntary reflex coupled to the primary esophageal peristaltic wave.

Question 16

Where is the swallowing center?

Answer 16

Reticular formation

Question 17

Pharyngeal phase is initiated by

Answer 17

bolus touching the pillars of faces, tonsils, soft palate, base of tongue and posterior wall of pharynx

Question 18

Primary peristaltic wave is initiated by

Answer 18

swallowing center

Question 19

Primary peristaltic wave is mediated by

Answer 19

Vagus to the striated circular and longitudinal muscles and to the myenteric plexus in the smooth muscle, thus, activating enteric system.

Question 20

Where does the primary peristaltic wave start?

Answer 20

Just below the sphincter and spreads downwards pushing bolus toward stomach

Question 21

Which neurotransmitters cause the wave of inhibition that relaxes the LES?

Answer 21

VIP and NO

Question 22

What is receptive relaxation

Answer 22

Temporary inhibition of resting tone in the funds and oral area.

Question 23

After the peristaltic wave passes the LES, the LES contracts to a level above resting tone. This is mediated by

Answer 23

Ach and enkephalins

Question 24

Secondary Peristalsis

Answer 24

Peristaltic wave not preceded by pharyngeal activity or relaxation of the UES. Functions to clear the esophagus of retained food and refluxed gastric contents.

Question 25

Secondary peristalsis is important for _____

Answer 25

Pregnant women

Question 26

Pinching action of the diaphragm on the esophagus is important for

Answer 26

Infants

Question 27

Retching

Answer 27

movement of contents into the esophagus but with inadequate force to move contents through UES.

Question 28

Storage function of the stomach is accomplished by ______ and _______

Answer 28

Receptive relaxation and accommodation

Question 29

Accommodation

Answer 29

muscle relaxation in response to stretching or distention by food.

Question 30

Which part of the stomach is the storage site

Answer 30

Upper part

Question 31

How is housekeeping done in the stomach?

Answer 31

Achieved by migrating myoelectric complexes (MMCs)

Question 32

MMCs

Answer 32

occur only during interdigestive periods and sweep luminal contents out of stomach and down small intestine into the large intestine.

Question 33

Antral Systole

Answer 33

Simultaneous contraction of the terminal antrum and pylorus.

Question 34

Relationship of tonicity and gastric emptying

Answer 34

Isotonic > hypotonic > hypertonic

Question 35

Relationship of types of materials and gastric emptying

Answer 35

Carbs > proteins > fats

Question 36

What mediates MMCs?

Answer 36

Motilin

Question 37

Is the pylorus open or closed in MMCs?

Answer 37

Open to empty out stomach

Question 38

Muscularis mucosal and villus muscle activity is responsible for

Answer 38

movement of mucosa and villi

Question 39

Muscularis external activity is responsible for

Answer 39

intraluminal mixing and propulsion.

Question 40

Which cells are responsible for electrical control activity?

Answer 40

Interstitial cells of Cajal that lie between the circular and longitudinal muscle layers

Question 41

What are spike potentials?

Answer 41

Local events on the plateau of ECAs. These are called ERAs.

Question 42

What is the effect of neuroendocrine agents on ECAs?

Answer 42

It can only mediate but not initiate ECAs. That input induce ERAs.

Question 43

In the stomach and intestine, peristalsis is a wave of

Answer 43

1) contraction of the longitudinal muscle and relaxation of the circular muscle aboral to a site.
2) relaxation of the longitudinal muscle and contraction of the circular muscle oral to, and at, the site.

Question 44

Factors that reduce the movement of Chyme

Answer 44

1) Morphine
2) Adynamic ileus
3) Gaseous distention

Question 45

Effect of morphine on movement of chyme

Answer 45

Morphine causes a reduction of enteric inhibitory neuron activity that results in a generalized increase in the tone of GI muscles.

Question 46

What are the functions of ileocecal sphincter?

Answer 46

1) delay transit of chyme into the colon.

2) prevent bacterial overgrowth in the ileum

Question 47

Effect of Caster Oil (ricinoleic acid)

Answer 47

Decreases resistance to movement of chyme/feces by inhibiting generalized contractions. Results in diarrhea.