What is the primary function of the small intestine in the digestive system?
- A. Absorption of nutrients
- B. Mechanical digestion of food
- C. Production of digestive enzymes
- D. Storage of bile
Correct Answer: A
Rationale: The primary function of the small intestine is the absorption of nutrients. Step 1: Digestive enzymes break down food in the small intestine. Step 2: Villi and microvilli in the intestine absorb nutrients like glucose and amino acids. Step 3: Nutrients are then transported to the bloodstream for distribution to cells. Thus, choice A is correct. Choices B and C are incorrect because mechanical digestion primarily occurs in the stomach, and digestive enzymes are produced by other organs like the pancreas. Choice D is incorrect as the small intestine does not store bile; it is produced by the liver and stored in the gallbladder.
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The enteric plexus in the tunica submucosa is called the ______ plexus.
- A. Meissner's
- B. Auerbach's
- C. myenteric
- D. solar
Correct Answer: A
Rationale: The correct answer is A: Meissner's plexus. Meissner's plexus is located in the tunica submucosa and is responsible for controlling the movements of the muscularis mucosae. It regulates local blood flow, secretion, and absorption in the small intestine. Auerbach's plexus, located in the muscularis externa, controls the motility of the muscular layer. Myenteric plexus is another name for Auerbach's plexus. Solar plexus is a network of nerves located in the abdomen, not specifically related to the enteric plexus.
You're caring for Beth who underwent a Billroth II procedure (surgical removal of the pylorus and duodenum) for treatment of a peptic ulcer. Which findings suggest that the patient is developing dumping syndrome, a complication associated with this procedure?
- A. Flushed, dry skin
- B. Headache and bradycardia.
- C. Dizziness and sweating.
- D. Dyspnea and chest pain.
Correct Answer: C
Rationale: Rationale: Dumping syndrome is a common complication post-Billroth II procedure due to rapid emptying of gastric contents into the small intestine. Choice C (dizziness and sweating) align with early dumping syndrome symptoms like vasomotor symptoms and hypoglycemia. Flushed, dry skin (A) is not typical, headache and bradycardia (B) are more indicative of vagal reaction, and dyspnea and chest pain (D) are not usually associated with dumping syndrome.
Which of the following is the most plausible explanation for the protective effect of dietary fibre against cancer of the colon?
- A. Propionic acid, formed during colonic fibre fermentation inhibits liver fatty acid synthesis
- B. Butyric acid, formed during colonic fibre fermentation stimulates 'silencing' of the SLC5A8 tumour suppressor gene
- C. None of these options are correct
- D. Butyric acid, formed during colonic fibre fermentation stimulates anti-oxidant defences in the colon
Correct Answer: D
Rationale: The correct answer is D because butyric acid, a short-chain fatty acid formed during colonic fiber fermentation, has been shown to stimulate antioxidant defenses in the colon. This helps protect against oxidative damage, a key factor in the development of cancer. Choice A is incorrect because propionic acid does not inhibit liver fatty acid synthesis in relation to colon cancer. Choice B is incorrect because butyric acid does not silence the SLC5A8 tumor suppressor gene; in fact, it has been shown to have anti-tumor effects. Choice C is incorrect as there is evidence supporting the protective effect of dietary fiber through butyric acid's stimulation of antioxidant defenses.
Which of these is involved in the chemical digestion of protein?
- A. pancreatic amylase
- B. trypsin
- C. sucrase
- D. pancreatic nuclease
Correct Answer: B
Rationale: The correct answer is B: trypsin. Trypsin is an enzyme produced by the pancreas that specifically breaks down proteins into smaller peptides. It works in the small intestine to continue the process of protein digestion. Pancreatic amylase (A) breaks down carbohydrates, sucrase (C) breaks down sucrose, and pancreatic nuclease (D) breaks down nucleic acids, not proteins. Therefore, trypsin is the only enzyme involved in the chemical digestion of protein among the choices provided.
Which part of the digestive system is responsible for the absorption of nutrients?
- A. small intestine
- B. stomach
- C. pancreas
- D. liver
Correct Answer: A
Rationale: The correct answer is A, the small intestine, because it is the primary site for nutrient absorption in the digestive system. The small intestine is lined with villi and microvilli, increasing its surface area for efficient absorption. It contains specialized cells that transport nutrients into the bloodstream for distribution to the body. The stomach (B) primarily breaks down food using digestive enzymes and acids, while the pancreas (C) secretes digestive enzymes but does not directly absorb nutrients. The liver (D) plays a role in bile production and detoxification, but nutrient absorption occurs mainly in the small intestine.