45- Nutrition & Digestive Systems

Match the essential nutrient category with the probable effects a deficiency might cause.
1. Muscle loss, weakened immune system.
2. Hair loss, dry skin.
3. Muscle weakness, weight loss.

Match the essential nutrient category with the probable effects a deficiency might cause.
1. Muscle loss, weakened immune system.
2. Hair loss, dry skin.
3. Muscle weakness, weight loss.

Fats (2)
Carbohydrates (3)
Proteins (1)

Birds store food in a modified portion of the lower esophagus called the

A. crop.
B. epiglottis.
C. gizzard.
D. alimentary canal.
E. pharynx.

A. crop.

In the mammalian digestive system, what is the primary site of nutrient absorption?

A. pharynx
B. stomach
C. small intestine
D. large intestine
E. pancreas

C. small intestine

In the stomach, food processing continues and secretions from stomach glands aid the initial digestion of

A. carbohydrates.
B. lipids.
C. nucleic acids.
D. proteins.
E. vitamins.

D. proteins.

The process of emulsification is crucial to the digestion of

A. carbohydrates.
B. lipids.
C. nucleic acids.
D. proteins.
E. bile salts.

B. lipids.

The diarrhea that is a symptom of diseases like cholera is due to problems in the function of the

A. stomach.
B. small intestine.
C. large intestine.
D. appendix.
E. gall bladder.

C. large intestine.

Cows are able to survive on a diet consisting almost entirely of cellulose because

A. cows are autotrophic.
B. cows can manufacture all 20 amino acids out of sugars in the liver.
C. unlike humans, the saliva the cow produces has enzymes capable of digesting cellulose.
D. cows have cellulose-digesting, symbiotic microorganisms in their rumens.

D. cows have cellulose-digesting, symbiotic microorganisms in their rumens.

What is peristalsis?

A. a process of fat emulsification in the small intestine
B. voluntary control of the rectal sphincters regulating defecation
C. the transport of nutrients to the liver through the hepatic portal vein
D. loss of appetite, fatigue, dehydration, and nervous disorders
E. smooth muscle contractions that move food through the alimentary canal

E. smooth muscle contractions that move food through the alimentary canal

Most nutrients are absorbed across the epithelium of the

A. colon.
B. stomach.
C. esophagus.
D. small intestine.
E. large intestine.

D. small intestine.

One function of HCl secreted in the stomach is to convert pepsinogen into the active enzyme pepsin. Why don't stomach cells simply secrete pepsin instead?
A. Adequate amounts of pepsin are already manufactured by the pancreas.
B. Only the pepsinogen version is able to stabilize fat-water emulsions.
C. Pepsin is denatured and rendered inactive in solutions with low pH.
D. If cells produced active pepsin, they would digest their own cellular proteins.

D. If cells produced active pepsin, they would digest their own cellular proteins.

How does the digestion and absorption of fat differ from that of carbohydrates?

A. Processing of fat does not require any digestive enzymes, whereas the processing of carbohydrates does.
B. Fat absorption occurs in the stomach, whereas carbohydrates are absorbed from the small intestine.
C. Carbohydrates need to be emulsified before they can be digested, whereas fats do not.
D. Most absorbed fat enters the lymphatic system, whereas carbohydrates directly enter the blood.
E. Fat must be partially digested by bacteria in the large intestine before it can be absorbed, which is not the case for carbohydrates.

D. Most absorbed fat enters the lymphatic system, whereas carbohydrates directly enter the blood.

The glandular secretions involved in digestion that would most likely be released as inactive precursors are

A. protein-digesting enzymes
B. fat-solubilizing bile salts
C. acid-neutralizing bicarbonate
D. carbohydrate-digesting enzymes

A. protein-digesting enzymes

The lacteal, a lymphatic vessel in the center of each intestinal villus, functions in digestion by absorbing

A. carbohydrates.
B. proteins.
C. nucleic acids.
D. vitamin C.
E. lipids.

E. lipids.

A mechanism shared by both extracellular and intracellular digestion is

A. the ability to phagocytose food particles.
B. a slow speed of digestion.
C. the presence of a digestive cavity.
D. the ability to consume both large and small food items.

A. the ability to phagocytose food particles.

Bile is crucial for ______ digestion because of its function in _____.

A. protein, protecting the stomach lining
B. fat, solubilizing glycerol:fatty acid bonds
C. nucleic acids, uncoiling DNA strands
D. fat, emulsification
E. protein, lyophilization

D. fat, emulsification

Contrary to popular belief, stress is not usually the primary cause of ulcers, and many patients with ulcers do not over-produce acid. What Nobel prize-winning discovery demonstrated a previously unknown cause of ulcers?

A. greater acid concentrations in the stomach, lower esophagus, and duodenum
B. the eroding effect of certain spicy foods on the lining of the esophagus
C. the existence of a bacterial infection in the stomachs of most patients with ulcers
D. genetically predetermined weakness in the walls of the intestinal tract

C. the existence of a bacterial infection in the stomachs of most patients with ulcers

Blockage of the common bile duct would be expected to affect

A. lipid digestion.
B. protein digestion.
C. carbohydrate digestion.
D. nucleotide digestion.
E. cellulose digestion.

A. lipid digestion.

Cats cannot synthesize the amino acid taurine. This means that in cats, taurine

A. is not a required nutrient.
B. is an essential amino acid.
C. must be stored in cellular compartments.
D. is not present in their normal diet.

B. is an essential amino acid.

Humans are susceptible to scurvy because

A. they cannot synthesize amino acids.
B. they do not have enough adipose tissue for vitamin A storage.
C. they cannot synthesize vitamin C.
D. they have a high incidence of fruit allergies.
E. constant seasickness and nausea on long voyages leads to weakness and anemia.

C. they cannot synthesize vitamin C.

How do carnivores and herbivores differ?

A. Carnivores must eat more frequently than herbivores.
B. Carnivores and herbivores require different enzymes to digest their food.
C. Carnivores can be opportunistic but herbivores cannot.
D. Herbivores can be opportunistic but carnivores cannot.
E. Herbivores remain herbivores at all stages of development, while carnivores are often herbivores in their larval stages.

B. Carnivores and herbivores require different enzymes to digest their food.

A digestive cavity in which food enters an opening at one end and passes through the animal in one direction as it is digested is called the

A. gastrovascular cavity.
B. stomach.
C. alimentary canal.
D. epithelial cavity.
E. intestine.

C. alimentary canal.

Which type of nutrient can pass across epithelial cells without any expenditure of ATP?

A. iron
B. calcium
C. protein
D. fat
E. magnesium

D. fat

Salivary glands secrete _________ to start the digestion of _________.

A. amylase; starch
B. trypsin; proteins
C. amylase; fats
D. pepsin; proteins
E. lactase; milk

A. amylase; starch

In ruminants, cellulose digestion occurs in the

A. omasum.
B. rumen.
C. reticulum.
D. cecum.
E. rumen and reticulum

E. rumen and reticulum

The surface area of the small intestine is dramatically increased due to the presence of _________ on the luminal surface.

A. villi and microvilli
B. lacteals
C. capillaries
D. hydrolytic enzymes
E. smooth muscle

A. villi and microvilli

Surgical removal of the pancreas would

A. increase the acidity of the small intestine.
B. prevent the production of chyme in the stomach.
C. eliminate the ability to store bile in the gallbladder.
D. block the secretion of bile.
E. All of these changes would be a result of pancreas removal.

A. increase the acidity of the small intestine.

The large intestine concentrates undigested material by

A. absorption of salts and water across the epithelial surface of the lumen.
B. ingestion of excess salts and water by intestinal bacteria.
C. transporting excess salts and water back to the small intestine for absorption.
D. storing excess salts and water in the cecum.

A. absorption of salts and water across the epithelial surface of the lumen.

Oral rehydration solutions that contain both salt and glucose are highly effective in treating severe dehydration caused by diarrhea and vomiting. However, glucose or salt alone are not effective. Why?

A. Sodium transport and glucose transport are coupled in the small intestine so that glucose accelerates absorption of salt and water.
B. Water alone rushes through the digestive tract too quickly to be absorbed by the body tissues.
C. ATP is required to transport sodium unless glucose is available for cotransport.
D. Glucose without sodium is broken down too quickly in the mouth by saliva.

A. Sodium transport and glucose transport are coupled in the small intestine so that glucose accelerates absorption of salt and water.

How did Bayliss and Starling demonstrate that the small intestine secretes chemical signals that stimulate the pancreas to respond to acid?

A. They injected acid into a dog's small intestine after dissecting away all the nerves.
B. They exposed a dog's small intestine to a cell extract made from a second dog's small intestine that had been exposed to acid.
C. They cut out a piece of the small intestine and exposed it to acid.
D. They injected pancreatic secretions from a dog previously exposed to acid into the small intestine of a second dog.
E. They injected acid into the pancreas after removing all of its innervation

B. They exposed a dog's small intestine to a cell extract made from a second dog's small intestine that had been exposed to acid.

T/F. The small intestine releases the hormone secretin in response to acid.

TRUE

T/F. Fats packaged in chylomicrons pass directly from epithelial cells to the bloodstream

FALSE

T/F. In the stomach, proteins are cleaved into amino acids by aminopeptidases

FALSE

T/F. A person whose ancestors were cattle herders is more likely to express the lactase gene as an adult.

TRUE

T/F. All sugars are absorbed via secondary active transport.

FALSE

T/F. In omnivores, including humans, the cecum is an important organ for digestion of cellulose.

FALSE

T/F. Fat absorbed by the small intestine enters the lymphatic system.

TRUE

T/F. Frugivores are a type of herbivore.

TRUE

T/F. The only chyme molecule that is absorbed in significant amounts by the stomach is water.

TRUE