Chapter 7, Problem 11RQ

Figure 34.11 Which of the following statements about the digestive system is false? Chyme is a mixture of food and digestive juices that is produced in the stomach. Food enters the large intestine before the small intestine. In the small intestine, chyme mixes with bile, which emulsifies fats. The stomach is separated from the small intestine by the pylloric sphincter.

Figure 34.19 Which of the following statements about digestive processes is true? Amylase, maltaseT and lactase in the mouth digest carbohydrates. Trypsin and lipase in the stomach digest protein. Bile emulsifies lipids in the small intestine. No food is absorbed until the small intestine.

Which of the following statements is not true? a. Essential nutrients can be synthesized by the body. b. Vitamins are required in small quantities for bodily function. c. Some amino acids can be synthesized by the body, while others need to be obtained from diet. d. Vitamins come in two categories: fat-soluble and water-soluble.

Different regions of the digestive system specialize in ________ and _________ food and in __________ unabsorbed food residues.

Bile has a role in _________ digestion and absorption. a. carbohydrate c. protein b. fat d. amino acid

The food label in Figure 11.28 lists the nutrients and other substances in a package of ready-to-eat macaroni and cheese. Based on your reading in this chapter, how would you rate this products healthiness in terms of fats and carbohydrates? Figure 11.28 Food labels are useful health tools. Information on a food label can be used to ensure that you get the nutrients you need without exceeding recommended limits on less healthy substances such as salt, sugar, and trans fats. At present, the USDA is considering major revisions to food labels. The proposed changes include showing realistic serving sizes and sugars added by the manufacturer, and printing the calorie content per serving in larger, bolder type so that it is easier for consumers to make informed choices about purchases of prepared foods. (Left: USDA, US Department of Agriculture; Right: FoodCollection/SuperStock)

Using the black lines shown in Figure 11.27, name the types of nutrient molecules present at each site that are small enough to be absorbed across the small intestines lining. Figure 11.27 Fill in the blanks for substances that cross the lining of the small intestine.

The pH of human stomach acid ranges from 1.0 to 3.0, whereas a healthy esophagus has a pH of approximately 7.0. In gastroesophageal reflux disease (GERD), often called acid reflux, stomach acid flows backward from the stomach into the esophagus. Repeated episodes in which esophageal pH goes below 4.0, considered clinical acid reflux, can result in bleeding ulcers and damage to the esophageal lining. The data in the Figure, from a patient with GERD, show esophageal pH during a sleeping reflux event. How many minutes does it take to go from the peak of the reflux event (when pH is most acidic) to when the reflux event is over? Source: Based on T. Demeester et al. 1976. Patterns of gastroesophageal reflux in health and disease. Annals of Surgery 184:459469.