Question 1

The liver receives venous blood coming directly from the digestive tract, and arterial blood coming from the aorta.

Accepted Answer

This is true. The liver receives a dual blood supply from both the portal vein (which carries blood from the digestive tract) and the hepatic artery (which carries oxygen-rich blood from the aorta).

Question 2

Bile is secreted continuously by the gallbladder.

Accepted Answer

Bile is not secreted continuously by the gallbladder. It is stored and concentrated in the gallbladder between meals, and is released in response to the hormone cholecystokinin when food enters the small intestine.

Question 3

In cirrhosis, damaged hepatocytes are permanently replaced by an overgrowth of connective tissue.

Accepted Answer

Cirrhosis is a condition in which scar tissue replaces healthy liver tissue, leading to decreased liver function. This scar tissue is an overgrowth of connective tissue, and cannot be reversed or repaired, meaning that the damaged hepatocytes are permanently replaced by this scar tissue.

Question 4

Bile salts are important in fat digestion and absorption.

Accepted Answer

Bile salts emulsify and break down fats in the small intestine, making it easier for enzymes to digest and absorb them.

Question 5

The main function of the ileocecal valve/sphincter is to prevent small intestinal contents from entering the large intestine before digestion of food is completed.

Accepted Answer

The main function of the ileocecal valve, also known as the ileocecal sphincter, is to prevent the backflow of contents from the large intestine into the small intestine, rather than to prevent small intestinal contents from entering the large intestine before digestion is completed. It allows digested food materials to pass from the small intestine to the large intestine.

Question 6

CCK causes relaxation of the sphincter of Oddi.

Accepted Answer

CCK (cholecystokinin) causes relaxation of the sphincter of Oddi, which allows bile and pancreatic juice to enter the duodenum.

Question 7

The small intestinal epithelium actively secretes digestive enzymes into the intestinal lumen.

Accepted Answer

The small intestinal epithelium primarily absorbs nutrients and does not secrete digestive enzymes; these enzymes are secreted by the pancreas and enter the intestine via the pancreatic duct.

Question 8

The primary factor responsible for forward propulsion of chyme through the small intestine is mass movements.

Accepted Answer

The primary factor responsible for forward propulsion of chyme through the small intestine is peristalsis, not mass movements. Mass movements are more characteristic of the large intestine.

Question 9

Microvilli establish a brush border in the small intestine.

Accepted Answer

Microvilli are small, finger-like projections on the surface of the intestinal cells that increase the surface area for absorption of nutrients. When numerous microvilli are present, they form the brush border, which gives the surface of the small intestine a fuzzy appearance.

Question 10

Protein digestion begins in the stomach under the influence of pepsinogen, continues in the duodenal lumen under the influence of pancreatic proteolytic enzymes, and is completed intracellularly in the small intestinal brush border.

Accepted Answer

This is a correct statement about protein digestion. Pepsinogen is converted to active pepsin in the acidic environment of the stomach and breaks down proteins into smaller peptide fragments. Pancreatic proteolytic enzymes, including trypsin, chymotrypsin, and carboxypeptidase, further break down these peptides in the duodenum. The final step of protein digestion occurs in the brush border of the small intestine, where peptidases on the surface of enterocytes hydrolyze peptides into amino acids that can be absorbed into the bloodstream.

Question 11

The principal clinical manifestation of pancreatic exocrine insufficiency is incomplete protein digestion resulting from deficiency of the powerful pancreatic proteolytic enzymes.

Accepted Answer

The principal clinical manifestation of pancreatic exocrine insufficiency is malabsorption of fats due to a deficiency in pancreatic lipase, leading to steatorrhea (fatty stools).

Question 12

The ileocecal juncture serves as a barrier to prevent bacteria-laden contents of the large intestine from contaminating the small intestine.

Accepted Answer

The ileocecal juncture is the entrance point for contents of the large intestine into the small intestine. It is guarded by a sphincter muscle which helps prevent the backflow of contents. This barrier is important in preventing the contamination of the small intestine by bacteria from the large intestine.

Question 13

Excessive small intestinal motility can lead to constipation because there is less time for absorption to take place.

Accepted Answer

Excessive small intestinal motility would actually lead to diarrhea, not constipation. When the small intestine moves too quickly, there is less time for absorption to take place, which can result in loose or watery stools.

Question 14

Bilirubin aids fat digestion and absorption.

Accepted Answer

Bilirubin is a waste product from the breakdown of red blood cells and plays no role in fat digestion and absorption. The liver produces bile which aids in the emulsification and absorption of fats.

Question 15

Migration of a new intestinal epithelial cell from the crypt at the base of the villus to the tip of the villus requires about three weeks.

Accepted Answer

Migration of a new intestinal epithelial cell from the crypt at the base of the villus to the tip of the villus typically takes about 3 to 5 days, not three weeks.

Question 16

Bile salts are derivatives of cholesterol.

Accepted Answer

Bile salts are synthesized from cholesterol in the liver and are important in the digestion and absorption of fats in the small intestine.

Question 17

The main motility seen in the small intestine during digestion of a meal is the migrating motility complex.

Accepted Answer

The main motility seen in the small intestine during digestion of a meal is segmentation, not the migrating motility complex (MMC). The MMC occurs in a fasted state, not during digestion.

Question 18

Glycogen is stored in the liver.

Accepted Answer

Glycogen is primarily stored in the liver and muscles. In the liver, glycogen serves as a source of glucose for the body and helps to maintain blood glucose levels. In the muscles, glycogen is used as a source of energy during physical activity.

Question 19

Digestive enzymes produced by the small intestine are not secreted into the lumen but act intracellularly.

Accepted Answer

Digestive enzymes produced by the small intestine are secreted into the lumen and act extracellularly, not intracellularly.

Question 20

Bile is secreted by the liver and stored and concentrated in the gallbladder.

Accepted Answer

This is correct. Bile is produced by the liver and stored in the gallbladder until it is needed for digestion in the small intestine.

Quiz 15: The Digestive System