Which one of the following is the stimulus that causes the release of secretin?  

For both defecation and urination, the internal sphincters allowing exit of feces or urine are under involuntary control, while the external sphincters are under voluntary control (e.g. you choose when to open them).

What type of muscle are the internal and external sphincters made of and what part of the nervous system controls them to explain why one set is involuntary and the other voluntary? [Use the options in brackets as possible answer choices.]

A. Internal sphincter muscle type [skeletal, smooth, or cardiac]

B. Internal sphincter nervous system [somatic, sympathetic, parasympathetic]

C. External sphincter muscle type [skeletal, smooth, or cardiac]

D. External sphincter nervous system [somatic, sympathetic, parasympathetic]

Which organ produces bile?

Which of the following changes in intestinal function promote(s) diarrhea?

Which division of the nervous system is responsible for stimulating contraction of the rectum and opening of the internal anal sphincter as part of the defecation reflex?

Name the sphincter that remains open during acid reflux events, thus allowing acidic stomach contents into the esophagus.

Which one of the following structures is found in the stomach but nowhere else in the GI tract?

Which GI hormone is released due to the presence of fat in the duodenal lumen and in response promotes increased secretion of pancreatic digestive enzymes from acinar cells?

What type of epithelium is part of the mucosal layer of the small intestinal wall?

Digestion and absorption of which one of the following macromolecules would be affected the most if the liver was severely damaged?