Question 1

Most nutrients are absorbed through the mucosa of the intestinal villi by active transport.

Accepted Answer

Active transport is the process by which nutrients are absorbed through the mucosa of the intestinal villi.

Question 2

Which of the following is the best illustration of the difference between metabolism and digestion?

Accepted Answer

Metabolism encompasses all the chemical reactions that occur within the cells of the body, including the breakdown of food molecules that were previously digested in the G.I. tract. Digestion, on the other hand, is specifically related to the breakdown of food molecules into smaller components that can be absorbed and utilized by the body. Therefore, option C best illustrates the difference between Metabolism and Digestion.

Question 3

The enterohepatic circulation reabsorbs bile salts in the distal portion of the small intestine (ileum).All of the following statements about the enterohepatic circulation are true except one.Select the statement below that is not true of the enterohepatic circulation?

Accepted Answer

While it is true that bile salts are reabsorbed and reused in the enterohepatic circulation, not all components of bile are recycled. For example, cholesterol is not efficiently reabsorbed and is often lost in feces, while bilirubin is largely disposed of in the feces as well.

Question 4

Which of the organs listed below is involved in all of the following processes: secretion,mechanical breakdown of food,digestion and absorption?

Accepted Answer

The stomach is involved in all of the listed processes. It secretes acid and enzymes to aid in digestion, mechanically breaks down food through muscular contractions, digests proteins and some fats, and absorbs certain nutrients such as alcohol and aspirin. The esophagus is only involved in transporting food to the stomach, the sigmoid colon and large intestines are mainly involved in reabsorption of water and electrolytes rather than digestion and absorption of nutrients.

Question 5

Fat absorption through the plasma membrane of epithelial cells ________.

Accepted Answer

Fat absorption through the plasma membrane of epithelial cells occurs by simple diffusion because lipids, being hydrophobic, can easily penetrate the hydrophobic fatty acid tails within the plasma membrane without the need for transport proteins or energy expenditure.

Question 6

Severe diarrhea can diminish potassium ion absorption.

Accepted Answer

Severe diarrhea can lead to dehydration and loss of electrolytes, including potassium ions. This loss can reduce the absorption of potassium ions in the body.

Question 7

Mumps is an inflammation of the parotid glands caused by myxovirus.

Accepted Answer

Mumps is indeed an inflammation of the parotid glands caused by myxovirus.

Question 8

Which of the following is least involved in the mechanical breakdown of food,digestion or absorption of nutrients?

Accepted Answer

The esophagus is primarily involved in the transportation of food from the oral cavity to the stomach through peristalsis and does not play a significant role in the mechanical breakdown of food, digestion, or absorption of nutrients.

Question 9

The soft palate reflexively opens the nasopharynx to allow the passage of food,which is now called a bolus.

Accepted Answer

The soft palate reflexively closes the nasopharynx during swallowing to prevent the passage of food into the nasal cavity, ensuring that the bolus moves down the esophagus.

Question 10

Which of the following is the best explanation of the benefit in the digestive system having the largest collection of lymphoid tissue (MALT)at the distal end of the small intestine?

Accepted Answer

The distal end of the small intestine is located before the large intestine, where large numbers of bacteria reside. Therefore, having the largest collection of lymphoid tissue at this location is important to prevent these bacteria from entering the lumen of the small intestine and being absorbed with food's nutrients into the bloodstream. This helps protect the body from harmful pathogens and maintain a healthy balance of beneficial bacteria in the gut.

Question 11

When swallowing,the epiglottis covers the larynx.

Accepted Answer

The epiglottis is a flap of tissue that covers the larynx during swallowing to prevent food or liquid from entering the airway. This allows food to pass down the esophagus and into the stomach.

Question 12

Most gastric ulcers are due to excessive production of hydrochloric acid.

Accepted Answer

Although excessive production of hydrochloric acid can contribute to gastric ulcers, the majority of cases are actually caused by infection with the bacterium Helicobacter pylori or use of nonsteroidal anti-inflammatory drugs (NSAIDs).

Question 13

All but one of the following is a function of the low pH found in the stomach.Select the description below that does not reflect a role of stomach acid.

Accepted Answer

The answer of All but one of the following is...

Question 14

Select the best explanation for why protease enzymes are secreted in inactive forms.

Accepted Answer

The secretion of protease enzymes in inactive forms helps to protect the cells producing them until they are safely within the lumen of the gastrointestinal tract. If the enzymes were active before they were secreted, they could damage the cells or tissues of the digestive organs. It also ensures proper regulation of the enzymatic activity in the digestive process.

Question 15

Fats significantly delay the emptying of the stomach through hormonal and neuronal signals.

Accepted Answer

Fats take longer to digest and absorb compared to other nutrients, so they delay the emptying of the stomach, which in turn affects hunger and satiety signals. This delay is mediated by hormones (such as cholecystokinin and peptide YY) and neural signals that regulate the movement of food through the digestive system.

Question 16

Bile salts bind at their hydrophobic regions to large fat globules within the chyme that enters the duodenum.Bile salts break up the fat globule into smaller fat droplets.This role of bile salts is best described as ________.

Accepted Answer

Bile salts function as emulsifiers, breaking up large fat globules into smaller droplets to increase surface area for enzymes to digest lipids. This process is called lipid emulsification.

Question 17

The major stimulus for production of intestinal fluid is distention or irritation of the intestinal mucosa by hypertonic or acidic chyme.

Accepted Answer

Intestinal distention or irritation by hypertonic or acidic chyme is a major stimulus for the production of intestinal fluid.

Question 18

A doctor consulting a patient that recently has had their gall bladder removed would likely advise ________.

Accepted Answer

Since the gallbladder is responsible for storing and releasing bile, which helps digest fats, patients who have had their gallbladder removed are recommended to eat foods low in fat to prevent discomfort and digestive issues.

Question 19

Select the description below that illustrates a difference between a sphincter and circular muscle.

Accepted Answer

The description explains that a sphincter is a thickening of circular muscle that can prevent the movement of digesting materials, while circular muscle is involved in propelling digesting material. This illustrates a difference between the two types of muscles. Choice B is incorrect because circular muscle is found throughout the GI tract. Choice C is incorrect because both sphincters and circular muscle are composed of smooth muscle tissue. Choice D is incorrect because sphincters can be found in both the proximal and distal portions of the GI tract.

Question 20

A ruptured appendix is life threatening because ________.

Accepted Answer

A ruptured appendix is likely to cause massive infection of the abdominopelvic cavity, known as peritonitis. This can lead to sepsis and other life-threatening complications.

Quiz 23: The Digestive System