Nokea
Submucosal glands occur in the submucosa of the and they also occur in the _.
- A. Oesophagus and ileum
- B. Stomach and Duodenum
- C. Stomach and ileum
- D. Oesophagus and Duodenum
Correct Answer: B
Rationale: The correct answer is B: Stomach and Duodenum. Submucosal glands are found in the submucosa of the stomach and duodenum. In the stomach, these glands secrete mucus and bicarbonate to protect the lining from stomach acid. In the duodenum, they secrete mucus to protect the lining from the acidic chyme entering from the stomach. Choices A, C, and D are incorrect because submucosal glands are not typically found in the oesophagus or ileum. The rationale for the correct answer is based on the anatomical location and function of submucosal glands in the gastrointestinal tract.
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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 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.
Where does the majority of carbohydrate digestion occur?
- A. stomach
- B. small intestine
- C. mouth
- D. esophagus
Correct Answer: C
Rationale: The majority of carbohydrate digestion occurs in the mouth. This is because the enzyme amylase, present in saliva, begins breaking down carbohydrates into simpler sugars like maltose. The process starts in the mouth as the food is chewed and mixed with saliva, creating a bolus that can be easily swallowed. In the stomach, the acidic environment actually inhibits amylase activity, so minimal carbohydrate digestion occurs there. The small intestine is where further digestion and absorption of carbohydrates primarily happen, but the initial breakdown in the mouth is crucial. The esophagus is not involved in digestion, but rather in the transportation of food to the stomach.
Which organ has the most metabolically active cells?
- A. pancreas
- B. liver
- C. stomach
- D. small intestine
Correct Answer: B
Rationale: The correct answer is B: liver. The liver has the most metabolically active cells due to its crucial role in various metabolic processes, such as detoxification, protein synthesis, and glucose metabolism. It is responsible for producing enzymes and metabolizing nutrients. The pancreas, stomach, and small intestine are important organs, but they are not as metabolically active as the liver. The pancreas primarily produces digestive enzymes and regulates blood sugar levels. The stomach digests food, and the small intestine absorbs nutrients. However, in terms of overall metabolic activity, the liver surpasses these organs.
The function of the migrating motor
- A. is to:
- B. Empty non-digestable material from stomach and small intestine during fasting
- C. Initiate mass movements in the large intestine
- D. Increase intestinal peristalsis in response to overfeeding
Correct Answer: B
Rationale: The migrating motor complex (MMC) functions to clear non-digestible material from the stomach and small intestine during fasting periods. Step 1: During fasting, MMC promotes gastrointestinal motility to prevent bacterial overgrowth. Step 2: MMC consists of 3 phases - quiescent, irregular contractions, and intense contractions - aiding in sweeping undigested materials. Step 3: This process helps maintain gut health and prevents issues like bacterial overgrowth or malabsorption. Summary: Choices A, C, and D are incorrect as they do not accurately describe the specific function of the migrating motor complex during fasting.