ATI RN
NCLEX Questions Gastrointestinal System Questions
Question 1 of 5
The low pH of the stomach activates enzymes that digest ______ while inactivating enzymes that digest ______.
Correct Answer: B
Rationale: The correct answer is B because the low pH of the stomach activates pepsin, an enzyme that digests proteins, while inactivating salivary amylase, an enzyme that digests starch. Pepsin works optimally in an acidic environment, breaking down proteins into peptides. Salivary amylase, on the other hand, works best at a neutral pH and is denatured in the acidic stomach, leading to its inactivation. Choices A, C, and D are incorrect because lipids are primarily digested in the small intestine, and nucleic acids are not directly affected by the stomach's pH.
Question 2 of 5
In the small intestine, movement of chyme is regulated primarily by
Correct Answer: C
Rationale: The correct answer is C: local and mechanical stimulation. In the small intestine, movement of chyme is primarily regulated by local and mechanical stimulation, which triggers peristalsis and segmentation. This allows for the mixing and propulsion of chyme along the digestive tract. A: Secretin and cholecystokinin are hormones involved in regulating pancreatic and gallbladder secretions, not movement of chyme in the small intestine. B: The parasympathetic nervous system via the vagus nerve plays a role in stimulating digestive processes but is not the primary regulator of movement of chyme. D: The enterogastric reflex is related to regulating stomach emptying in response to irritating substances, not movement of chyme in the small intestine.
Question 3 of 5
In the production of the aqueous component of pancreatic juice, ______ ions are actively transported into the intercalated duct and sodium ions are exchanged for ______ ions.
Correct Answer: A
Rationale: The correct answer is A because in the production of pancreatic juice, bicarbonate ions are actively transported into the intercalated duct to ensure the alkalinity of the pancreatic juice. Additionally, sodium ions are exchanged for hydrogen ions to maintain the pH balance. This process helps neutralize the acidic chyme entering the small intestine from the stomach. The other choices are incorrect because potassium ions are not directly involved in this specific process, and the exchange of sodium ions for potassium ions does not contribute to the regulation of pancreatic juice pH.
Question 4 of 5
In the colon, the teniae coli are bands of ______, which contract to form ______.
Correct Answer: B
Rationale: The correct answer is B because the teniae coli are bands of longitudinal smooth muscle in the colon. These bands contract to form haustra, which are the pouches that give the colon its segmented appearance. Choice A is incorrect because fat and epiploic appendages are not involved in the contraction of the colon. Choice C is incorrect because the teniae coli are smooth muscle, not skeletal muscle. Choice D is incorrect because the internal anal sphincter is not formed by the contraction of the teniae coli.
Question 5 of 5
Cholesterol is a major component of atherosclerotic plaque. Cholesterol carried by ______ is linked to coronary heart disease.
Correct Answer: C
Rationale: The correct answer is C: low-density lipoprotein (LDL). LDL is often referred to as "bad cholesterol" because it carries cholesterol from the liver to the cells, leading to the buildup of plaque in the arteries, which can result in coronary heart disease. Micelles are small lipid structures, not carriers of cholesterol. Chylomicrons are large lipoprotein particles that transport dietary fats, not primarily cholesterol. HDL is known as "good cholesterol" as it helps remove cholesterol from the bloodstream back to the liver for excretion, reducing the risk of atherosclerosis.