A Critical Thinking Questions 1. Why does the GI tract have a plexus in the muscalaris and nerves in the mucosa? What
physiological functions of the tract are supported by these anatomical structures? Think about
your answer in the context of Hirschsprung's disease, a congenital disorder of the colon that
involves a defect in the myenteric plexus. What symptom or problem do you imagine the disease
would cause?
2. How and why does vomiting too often, for example for sufferers of bulimia, damage the digestive
system? Why are the stomach's gastric secretions harmful, but the oral secretions are not?
3. Name any two of the major types of chemical substances that are broken down in chemical
digestion. For each substance, name an enzyme that breaks them down and what final product is
actually absorbed by the body for use or storage.
4. Explain how enzymes assist the process of absorption.
5. Name at least two concrete, positive steps you can take to avoid contracting gastroenteritis (in
other words, Dos not DON'TS).