Nokea
Which enzyme is responsible for breaking down carbohydrates in the mouth?
- A. Amylase
- B. Protease
- C. Lipase
- D. Pepsin
Correct Answer: A
Rationale: The correct answer is A: Amylase. Amylase is an enzyme that specifically breaks down carbohydrates into sugars in the mouth. It is produced by both salivary glands and pancreas. Protease (B) breaks down proteins, Lipase (C) breaks down fats, and Pepsin (D) breaks down proteins in the stomach. Therefore, A is the correct answer for the enzyme responsible for breaking down carbohydrates in the mouth.
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Gastric secretions:
- A. Decrease when a person thinks of food.
- B. Contain a substance which is essential for absorption of vitamin B12 from terminal ileum.
- C. Contain HCL secreted by chief cells.
- D. Are essential for fat digestion and absorption.
Correct Answer: B
Rationale: Step-by-step rationale:
1. Gastric secretions contain intrinsic factor, essential for vitamin B12 absorption from the terminal ileum.
2. Intrinsic factor binds to vitamin B12 to facilitate its absorption.
3. Without intrinsic factor, vitamin B12 absorption is impaired, leading to pernicious anemia.
4. Therefore, choice B is correct.
Summary:
- Choice A is incorrect as gastric secretions increase, not decrease, when a person thinks of food.
- Choice C is incorrect as hydrochloric acid (HCl) is secreted by parietal cells, not chief cells.
- Choice D is incorrect as fat digestion primarily occurs in the small intestine with the help of pancreatic enzymes, not gastric secretions.
Which is not a feature of digestive motility?
- A. Peristalsis only involves forward movements
- B. Segmentation involves mechanical digestion of food
- C. Peristalsis is present in the oesophagus, stomach and small/large intestines
- D. Segmentation is present in the stomach, small and large intestines
Correct Answer: A
Rationale: The correct answer is A. Peristalsis involves coordinated waves of muscle contractions that propel food forward. However, peristalsis can also involve backward movements to help with mixing and digestion. Therefore, the statement that peristalsis only involves forward movements is incorrect. Segmentation involves mixing and breaking down food through contractions that occur in non-unidirectional patterns. Peristalsis can be found in the esophagus, stomach, and intestines, while segmentation is mainly present in the small intestine. Therefore, choices B, C, and D are incorrect based on the explanations provided.
Which of the following sports drinks would BEST promote BOTH glucose absorption and water absorption (hydration) during aerobic exercise?
- A. Drink A: 20% carbohydrate and sodium free
- B. Drink B: 8% carbohydrate and sodium free
- C. Drink C: 20% carbohydrate and contains sodium
- D. Drink D: 8% carbohydrate and contains sodium
Correct Answer: D
Rationale: The correct answer is D: Drink D with 8% carbohydrate and contains sodium. During aerobic exercise, glucose and sodium are crucial for optimal hydration and energy replenishment. The 8% carbohydrate concentration is within the recommended range for efficient glucose absorption, while the presence of sodium helps in fluid retention and electrolyte balance. Choices A and B lack sodium, which is necessary for hydration. Choice C has the right carbohydrate concentration but lacks sodium, making it less effective compared to Drink D.
If you place a pin through the greater omentum, through how many layers of simple squamous epithelium would the pin pass?
- B. 1
- C. 2
- D. 3
Correct Answer: C
Rationale: The correct answer is C (2 layers). The greater omentum consists of a double layer of peritoneum, which is a serous membrane composed of simple squamous epithelium. Therefore, when a pin is placed through the greater omentum, it would pass through two layers of simple squamous epithelium. Choice A (0) is incorrect because there are indeed layers of epithelium in the greater omentum. Choice B (1) is incorrect because there are two layers of epithelium. Choice D (3) is incorrect as there are only two layers to pass through.
The following is true about the small intestine:
- A. Stores food for several hours
- B. Is the main source of digestive enzymes
- C. Has haustrae
- D. Has segmentation contractions
Correct Answer: D
Rationale: The correct answer is D: The small intestine has segmentation contractions. This is because segmentation contractions are responsible for mixing and moving chyme (partially digested food) along the small intestine, allowing for optimal nutrient absorption. This process helps maximize the contact between chyme and the intestinal walls, facilitating absorption.
A: Incorrect. The small intestine does not store food for several hours; instead, it continuously processes and absorbs nutrients.
B: Incorrect. While the small intestine plays a crucial role in digestion and absorption, the main source of digestive enzymes is the pancreas.
C: Incorrect. Haustrae are found in the large intestine, not the small intestine. They aid in the absorption of water and electrolytes.