Nokea
The stomach is unique to the GI tract because it contains
- A. circular smooth muscle.
- B. longitudinal smooth muscle.
- C. skeletal muscle.
- D. oblique smooth muscle.
Correct Answer: D
Rationale: The correct answer is D: oblique smooth muscle. The stomach is unique in the GI tract because it contains an additional layer of muscle fibers called the oblique muscle layer. This layer allows for more efficient mixing and churning of food, aiding in digestion. Circular smooth muscle (choice A) and longitudinal smooth muscle (choice B) are present in various parts of the GI tract but are not unique to the stomach. Skeletal muscle (choice C) is not found in the stomach as the muscles responsible for its movement are smooth muscle.
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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.
Once chylomicrons leave the simple columnar epithelium of the small intestine, they diffuse into
- A. capillaries.
- B. lacteals.
- C. arterioles.
- D. venules.
Correct Answer: B
Rationale: The correct answer is B: lacteals. Chylomicrons are too large to enter capillaries directly, so they are absorbed into lacteals, specialized lymphatic vessels in the small intestine. Lacteals transport chylomicrons to the lymphatic system, eventually reaching the bloodstream via the thoracic duct. Arterioles and venules are part of the blood circulation system and are not directly involved in chylomicron absorption.
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.
Trypsinogen when activated by ______ will break down proteins in the ______.
- A. enterokinase; pancreatic ducts
- B. trypsin; small intestine
- C. secretin; pancreatic ducts
- D. enterokinase; small intestine
Correct Answer: D
Rationale: The correct answer is D: enterokinase; small intestine. Enterokinase is an enzyme that activates trypsinogen into trypsin in the small intestine. Trypsin is then responsible for breaking down proteins in the small intestine. Enterokinase is not found in the pancreatic ducts, eliminating choices A and C. Trypsinogen is not activated by itself, so choice B is incorrect. In summary, enterokinase activates trypsinogen into trypsin in the small intestine, allowing for protein digestion.
Which of the following vitamins is fat-soluble?
- A. B12
- B. C
- C. D
- D. E
Correct Answer: C
Rationale: The correct answer is C: D. Vitamin D is fat-soluble because it can be stored in the body's fatty tissues and liver. This allows for a slower release into the bloodstream when needed. Vitamins B12, C, and E are water-soluble, meaning they dissolve in water and are not stored in the body. Vitamin B12 is stored in the liver, but it is not considered fat-soluble. Vitamin C is excreted through urine, and Vitamin E is stored in body tissues but not in fat. Therefore, the only fat-soluble vitamin among the options provided is Vitamin D.