Nokea
The absorption of fructose by intestinal mucosa is
- A. co- transport mechanism
- B. simple diffusion
- C. facilitated transport
- D. active transport
Correct Answer: C
Rationale: The correct answer is C: facilitated transport. Fructose is absorbed through facilitated diffusion using specific carrier proteins in the intestinal mucosa. This process does not require energy input and allows fructose to move down its concentration gradient. Unlike active transport (requiring energy) and co-transport mechanisms (involving multiple substances), fructose absorption occurs through facilitated transport by specific carrier proteins. Simple diffusion is not the main mechanism for fructose absorption due to its hydrophilic nature. Thus, facilitated transport best describes how fructose is absorbed by the intestinal mucosa.
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The patient returned from a 6-week mission trip to Somalia with complaints of nausea, malaise, fatigue, and achy muscles. Which type of hepatitis is this patient most likely to have contracted?
- A. Hepatitis B (HBV)
- B. Hepatitis C (HCV)
- C. Hepatitis D (HDV)
- D. Hepatitis E (HEV)
Correct Answer: D
Rationale: The correct answer is D: Hepatitis E (HEV). The patient's symptoms of nausea, malaise, fatigue, and muscle aches are consistent with acute hepatitis, and HEV is commonly transmitted through contaminated water in developing countries like Somalia. Hepatitis B (HBV) and C (HCV) are more commonly transmitted through blood or body fluids. Hepatitis D (HDV) requires HBV for replication, making it less likely in this case. In summary, based on the patient's symptoms and travel history, Hepatitis E (HEV) is the most likely cause of the illness.
What is the function of the enteric nervous system?
- A. controlling voluntary movements
- B. regulating hormone secretion
- C. controlling digestion independently of the brain
- D. controlling respiratory functions
Correct Answer: C
Rationale: The correct answer is C because the enteric nervous system is a complex network of neurons that controls digestion independently of the brain. It regulates gastrointestinal functions such as peristalsis, secretion of digestive enzymes, and blood flow. This system can operate autonomously but is also influenced by the central nervous system. Choices A, B, and D are incorrect because the enteric nervous system is not responsible for controlling voluntary movements, regulating hormone secretion, or controlling respiratory functions.
Which of the following vitamins is not stored in the liver?
- A. C
- B. D
- C. B12
- D. A
Correct Answer: A
Rationale: The correct answer is A: Vitamin C. Vitamin C is water-soluble and not stored in the liver. It gets absorbed in the intestines and any excess is excreted in the urine. Vitamin D (choice B) is fat-soluble and stored in the liver. Vitamin B12 (choice C) is also stored in the liver. Vitamin A (choice D) is fat-soluble and stored in the liver as well. Thus, the correct answer is A as it is the only water-soluble vitamin among the options.
The Mallory-Weiss syndrome refers to the occurrence of gastrointestinal hemorrhage as a result of:
- A. esophageal varices
- B. esophageal peptic ulcers
- C. mucosal tears at the esophagogastric junction
- D. iatrogenic perforation
Correct Answer: C
Rationale: The Mallory-Weiss syndrome is characterized by mucosal tears at the esophagogastric junction. This occurs due to forceful or prolonged vomiting causing the tears in the mucosa. Esophageal varices (A) are dilated veins in the esophagus typically associated with liver disease, not related to Mallory-Weiss syndrome. Esophageal peptic ulcers (B) are erosions in the lining of the esophagus caused by acid reflux or infection, not a characteristic of Mallory-Weiss syndrome. Iatrogenic perforation (D) refers to accidental perforation caused during a medical procedure, not related to Mallory-Weiss syndrome. Therefore, the correct answer is C as it directly correlates with the characteristic presentation of Mallory-Weiss syndrome.
Which of the following organs is supported by a layer of adventitia rather than serosa?
- A. esophagus
- B. stomach
- C. small intestine
- D. large intestine
Correct Answer: A
Rationale: The correct answer is A: esophagus. The esophagus is supported by a layer of adventitia, which is a connective tissue layer, instead of serosa, a serous membrane. The esophagus is located in the thoracic cavity, where it is surrounded by connective tissue rather than a serous membrane like the other choices. The stomach, small intestine, and large intestine are all intraperitoneal organs, meaning they are covered by a serosa layer. The esophagus, being a retroperitoneal organ, lacks a serosa layer and is instead supported by adventitia. This structural difference is important for understanding the anatomy and function of these organs.