Exam 21: The Digestive System

Match the following structures with their functions. -organ where most digestion occurs

You are studying the toxic effects of a newly discovered tropical plant extract.From preliminary studies, it appears that the toxin prevents H⁺-dependent membrane transport.Explain which digestive processes may thus be impaired.

One way to determine the total energy in calories of a food is to burn it in a device called a bomb calorimeter.The heat produced during combustion minus the heat added to begin the combustion is the total calories in the food.The typical human digestive tract does not absorb all of the calories in food; thus it is not 100% efficient.Furthermore, calories in indigestible organic compounds may not be absorbed at all, and thus can be considered to be "zero calorie" relative to human nutrition.Artificial sweeteners and fats are designed to produce desired sensation in the mouth without being absorbed.These are organic compounds that would release heat in a bomb calorimeter, thus they technically have calories. A.What does this suggest about the accuracy of the bomb calorimeter in determining available food calories for humans? What would be the results of bomb calorimetry of human feces? B.What is it about a particular food substance that may prevent absorption of its calories? C.What happens to the "zero-calorie" molecules as they pass through the digestive tract? What are the potential effects on defecation?

The enteric nervous system and the CNS have several similarities.What are they?

Mucus functions in

Nutrient absorption occurs primarily in the

Match the structure or compound to its function. -basolateral transporter for ionized iron

A condition known as lactose intolerance is characterized by painful abdominal cramping, gas, and diarrhea.The cause of the problem is an inability to digest the milk sugar, lactose.How would this cause the observed symptoms? Why is yogurt less likely to trigger the symptoms?

Digestion refers to the

Where does carbohydrate digestion begin? Which enzyme is involved, and which reaction does it catalyze?

Match the structure to its function. -Protein digestion begins here.

Match the structure to its function. -Carbohydrate digestion is completed here.

Match the structure or compound to its function. -transporter for cholesterol absorption

The enzyme that digests starch into disaccharides is

Match the structure to its function. -Fat digestion begins here.

Rugae, plicae, and villi are all features that accomplish

Sandwiched between the layer of circular and longitudinal muscle in the muscularis externa is the

Match the following structures with their functions. -organ that adds secretions to the duodenum via a duct

Bile is

Features of the submucosa include