Why does the stomach's surface epithelium need to be replaced frequently?
Because mucus is rapidly lost from the surface
To keep gastric juice production constant
To increase the absorption of nutrients
Because the cells are often digested by stomach acid
The Correct Answer is D
A. Because mucus is rapidly lost from the surface: While mucus is constantly secreted, its loss is not the primary reason for cellular turnover. The mucus layer is a protective barrier for the cells beneath it. Cell replacement is a response to physical damage.
B. To keep gastric juice production constant: Gastric juice is produced by the deep glandular cells in the gastric pits, not the surface epithelium. The surface cells primarily provide a protective lining. Their turnover does not directly regulate the volume of acid.
C. To increase the absorption of nutrients: The stomach is not a primary site for nutrient absorption. Frequent epithelial turnover is a defensive strategy rather than an absorptive one. The villi of the small intestine handle the majority of nutrient uptake.
D. Because the cells are often digested by stomach acid: The harsh luminal environment, characterized by a pH of 1 to 2 and proteolytic pepsin, inevitably damages surface cells. Rapid mitosis allows the stomach to maintain its integrity. The entire lining is replaced every 3 to 6 days.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is C
Explanation
A. They close off the nasopharynx:The closure of the nasopharynx is performed by the elevation of the soft palate and uvula during the pharyngeal phase. This occurs before the bolus enters the esophagus. It is a muscular, not a glandular, function.
B. They produce enzymes for digestion:The esophagus is a conduit and does not participate in chemical digestion. No significant digestive enzymes are secreted by its mucosa. Its primary function is the rapid transport of the bolus to the stomach.
C. They lubricate the bolus to reduce friction:Esophageal glands secrete mucus that coats the luminal wall and the food bolus. This lubrication is essential for smooth peristaltic transit and protects the mucosa from mechanical abrasion. It facilitates an efficient, low-resistance passage.
D. They control the lower esophageal sphincter:The lower esophageal sphincter is a physiological high-pressure zone controlled by smooth muscle tone and vagal innervation. Glandular secretions do not influence the contraction or relaxation of this sphincter. It is regulated neurally and hormonally.
Correct Answer is C
Explanation
A. Portal triad:These structures are located at the periphery of the hexagonal hepatic lobule. They consist of a branch of the hepatic artery, portal vein, and bile duct. Blood flows from here toward the center, not outward.
B. Bile duct:This is a component of the portal triad that carries bile away from the hepatocytes toward the biliary tree. It is an excretory conduit located at the corners of the lobule. It does not serve as the central axis.
C. Central vein:This vessel sits at the geometric center of the hepatic lobule. Hepatocytes are arranged in cords or laminae that extend from this central point toward the periphery. This arrangement facilitates efficient exchange between blood and cells.
D. Hepatic artery:This is a terminal branch located within the portal triad at the lobule's edges. It supplies high-pressure, oxygenated blood to the sinusoids. It is not the central focal point for the radiating plates of hepatocytes.
Whether you are a student looking to ace your exams or a practicing nurse seeking to enhance your expertise , our nursing education contents will empower you with the confidence and competence to make a difference in the lives of patients and become a respected leader in the healthcare field.
Visit Naxlex, invest in your future and unlock endless possibilities with our unparalleled nursing education contents today
Report Wrong Answer on the Current Question
Do you disagree with the answer? If yes, what is your expected answer? Explain.
Kindly be descriptive with the issue you are facing.