The submucosa of the alimentary canal contains blood vessels, lymphatic vessels and a nerve plexus.
Correct Answer
True
True. The submucosa is dense connective tissue beneath the mucosa that carries blood and lymphatic vessels and the submucosal plexus, which helps regulate secretion.
Category: GI Tract Overview
Question 2
Parasympathetic stimulation generally decreases motility and secretion in the digestive tract.
Correct Answer
False
False. Parasympathetic stimulation, largely through the vagus nerve, generally increases digestive motility and secretion. Sympathetic stimulation is what tends to slow digestive activity.
Category: Digestive Regulation
Question 3
The hard palate is formed by bone, while the soft palate is composed mainly of skeletal muscle.
Correct Answer
True
True. The hard palate is formed by the maxillary and palatine bones, while the soft palate behind it is mostly skeletal muscle that can rise during swallowing.
Category: Mouth and Esophagus
Question 4
The esophagus lies anterior to the trachea in the thorax.
Correct Answer
False
False. The esophagus lies posterior to the trachea. The C-shaped tracheal cartilages are open at the back, so the esophagus can bulge forward slightly as a bolus passes.
Category: Mouth and Esophagus
Question 5
The muscularis of the lower third of the esophagus is skeletal muscle.
Correct Answer
False
False. The lower third of the esophagus has smooth muscle in its muscularis. The upper part is skeletal muscle and the middle portion contains both types.
Category: Mouth and Esophagus
Question 6
Intrinsic factor secreted by parietal cells is required for the absorption of vitamin B12.
Correct Answer
True
True. Intrinsic factor binds vitamin B12 so it can be absorbed in the ileum. Without it, vitamin B12 deficiency and pernicious anemia can develop.
Category: The Stomach
Question 7
The pyloric sphincter controls the passage of chyme from the stomach into the jejunum.
Correct Answer
False
False. The pyloric sphincter controls the passage of chyme from the stomach into the duodenum, the first segment of the small intestine.
Category: The Stomach
Question 8
The muscularis of the stomach has an inner oblique layer of smooth muscle in addition to circular and longitudinal layers.
Correct Answer
True
True. The extra oblique layer lets the stomach churn and mix food vigorously, which supports mechanical digestion and the formation of chyme.
Category: The Stomach
Question 9
Pepsin is most active in an alkaline environment.
Correct Answer
False
False. Pepsin is most active in the strongly acidic environment of the stomach. It loses activity when chyme is neutralized by bicarbonate in the duodenum.
Category: The Stomach
Question 10
Circular folds, villi and microvilli greatly increase the surface area of the small intestine for absorption.
Correct Answer
True
True. These three levels of folding multiply the absorptive surface of the small intestine many times over, which is why nearly all nutrient absorption happens there.
Category: Small and Large Intestines
Question 11
The ascending colon runs up the left side of the abdominal cavity.
Correct Answer
False
False. The ascending colon runs up the right side of the abdominal cavity from the cecum. The descending colon is the part on the left side.
Category: Small and Large Intestines
Question 12
Teniae coli are bands of longitudinal smooth muscle that gather the colon wall into pouches called haustra.
Correct Answer
True
True. The teniae coli are three bands of longitudinal smooth muscle in the colon wall, and their tone puckers the wall into a series of pouches called haustra.
Category: Small and Large Intestines
Question 13
The internal anal sphincter is made of skeletal muscle under voluntary control.
Correct Answer
False
False. The internal anal sphincter is smooth muscle under involuntary control. The external anal sphincter is the skeletal muscle sphincter under voluntary control.
Category: Small and Large Intestines
Question 14
The hepatic portal vein delivers nutrient-rich blood from the digestive organs to the liver.
Correct Answer
True
True. The hepatic portal vein carries blood from the stomach, intestines and spleen to the liver, so the liver can process absorbed nutrients and remove toxins before the blood reaches the rest of the body.
Category: Accessory Organs
Question 15
The gallbladder is the organ that produces bile.
Correct Answer
False
False. Bile is produced by the liver. The gallbladder stores bile and concentrates it until hormonal signals cause it to contract.
Category: Accessory Organs
Question 16
The common bile duct and the main pancreatic duct join at the hepatopancreatic ampulla before emptying into the duodenum.
Correct Answer
True
True. The two ducts merge at the hepatopancreatic ampulla, and a sphincter there controls the release of bile and pancreatic juice into the duodenum.
Category: Accessory Organs
Question 17
Most of the water absorbed by the digestive tract is absorbed in the large intestine.
Correct Answer
False
False. The small intestine absorbs most of the water that enters the digestive tract. The large intestine absorbs much of what remains and compacts the feces.
Category: Chemical Digestion
Question 18
Glucose is absorbed into intestinal epithelial cells by secondary active transport coupled to sodium ions.
Correct Answer
True
True. Glucose enters intestinal epithelial cells through carrier proteins that cotransport it with sodium ions, using the sodium gradient as the energy source. Fructose, by contrast, enters by facilitated diffusion.
Category: Chemical Digestion
Question 19
Chemical digestion of proteins begins in the mouth.
Correct Answer
False
False. Protein digestion begins in the stomach, where pepsin starts breaking proteins into smaller polypeptides. Saliva contains no protein-digesting enzyme.
Category: Chemical Digestion
Question 20
Ingestion, propulsion, mechanical digestion, chemical digestion, absorption and defecation are all digestive processes.
Correct Answer
True
True. Together these processes describe how food is taken in, moved along the tract, broken down physically and chemically, absorbed and finally eliminated as feces.
Category: Digestive Processes