PRACTICE QUESTIONS
1. A unique feature of gastrointestinal (GD smooth muscle cells is that:
a. Their resting Iranscellular electrical potential has the positive pole on the outside surface of the cell membrane.
b. Action potentials, or spikes of membrane depolarization, are not associated with muscle contractions.
c. Muscle contractions are stimulated by partial depolarization of the membrane.
d. There are spontaneous, rhythmical undulations in the electrical potential across the cell membrane.
e. Contraction of the muscles is never influenced by nervous activity.
2. The term slow waves as applied to the gut refers to:
a. Slowly moving fronts of electrical activity that are propagated down the enteric nervous system.
b. Slowly moving fronts of electrical activity that result from coordinated changes in cell membrane potential occurring throughout the smooth muscle of the intestinal wall.
c. Slowly moving fronts of ingesta that proceed down the intestine in response to peristaltic movement.
d. Slowly moving fronts of action potentials that are constantly passing over the gut smooth muscle.
e. Slowly moving fronts of peristaltic contractions that pass uniformly over the entire small intestine during the digestive period.
3. An animal is presented to you with aspiration pneumonia (the result of food material entering the lower respiratory tract). Which of the following lesions would be a likely cause?
a. Loss of myenteric plexus function in the pharynx and upper esophagus
b. Loss of slow-wave activity in the pharynx and upper esophagus
c. A lesion in the brainstem
d. A lesion in the trachea
e. None of the above
4. The term cephalic phase is used in reference to a number of activities occurring in the GI tract. In general, the term means:
a. The early phases of digestion, when food is nearest the head.
b. Any actions stimulated directly by the presence of food in the stomach.
c. Any actions stimulated directly by the presence of food in the mouth.
d. Digestive events stimulated by the presence of food in the GI tract, but requiring reflexes integrated in the central nervous system.
e. Digestive events that occur before the ingestion of food and in response to central nervous system stimulation that is brought on by the anticipation of eating.
5. Conditions in the duodenum, such as low pH or high fat concentration, can reflexively inhibit gastric emptying. Which reflex arc is involved in this inhibition?
a. Parasympathetic nervous system
b. GI enteric nervous system
c. GI endocrine system
d. All the above
6. Which of the following best describes the motility of the proximal region of the monogastric stomach?
a. Rhythmic segmentation
b. Peristalsis
c. Retropulsion
d. Adaptive relaxation
7. Which of the following is characteristic of the interdigestive phase of small intestinal motility?
a. Migrating motility complexes consisting of waves of peristaltic contractions that pass over the entire length of the small intestine
b. Rhythmic segmentation
c. Short waves of peristalsis that die out after a few centimeters
d. Complete relaxation of small intestinal smooth muscle
8. Which of the following aspects of colon physiology is common to many species, irrespective of interspecies anatomical differences in colon structure?
a. Rapid flow of ingesta
b. Adaptive relaxation
c. Retropulsion, or antiperistalsis
d. Haustra formation
9. Colonic “pacemakers":
a. are anatomically distinct structures composed of specialized smooth muscle cells.
b. shift in their sites under the influence of the ENS.
c. are involved in segmentation, but not peristalsis.
d. control defecation.
10. The Tectosphincteric reflex is integrated in the:
a. brain stem.
b. ENS.
c. lumbar spinal cord.
d. sacral spinal cord.