Nokea
Which part of a tooth most closely resembles bone tissue?
- A. enamel
- B. cementum
- C. dentin
- D. gingiva
Correct Answer: C
Rationale: The correct answer is C: dentin. Dentin is the part of the tooth that closely resembles bone tissue because it is a hard, dense tissue similar to bone in composition and structure, providing support and protection to the tooth. Dentin is located beneath the enamel and cementum, forming the bulk of the tooth structure. Enamel (choice A) is the hardest tissue in the body but is not similar to bone tissue in composition. Cementum (choice B) is a hard tissue covering the roots of teeth but is not as similar to bone tissue as dentin. Gingiva (choice D) is the soft tissue that surrounds the teeth and is not similar to bone tissue.
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The low pH of the stomach activates enzymes that digest ______ while inactivating enzymes that digest ______.
- A. lipids; proteins
- B. proteins; starch
- C. starch; proteins
- D. nucleic acids; starch
Correct Answer: B
Rationale: The correct answer is B because the low pH of the stomach activates pepsin, an enzyme that digests proteins, while inactivating salivary amylase, an enzyme that digests starch. Pepsin works optimally in an acidic environment, breaking down proteins into peptides. Salivary amylase, on the other hand, works best at a neutral pH and is denatured in the acidic stomach, leading to its inactivation. Choices A, C, and D are incorrect because lipids are primarily digested in the small intestine, and nucleic acids are not directly affected by the stomach's pH.
The nurse has completed initial instruction with a patient regarding a weight-loss program. Which patient comment indicates to the nurse that the teaching has been effective?
- A. I will keep a diary of daily weight to illustrate my weight loss.'
- B. I plan to lose 4 lb a week until I have lost the 60 lb I want to lose.'
- C. I should not exercise more than what is required so I don't increase my appetite.'
- D. I plan to join a behavior modification group to help establish long-term behavior changes.'
Correct Answer: D
Rationale: The correct answer is D because it demonstrates the patient's understanding of the importance of behavior modification for long-term weight loss success. By joining a behavior modification group, the patient shows a commitment to changing habits and lifestyle, which is crucial for sustained weight loss.
Choice A focuses on tracking weight loss progress, which is important but does not necessarily indicate a deep understanding of behavior change. Choice B sets unrealistic weight loss goals that may not be safe or sustainable. Choice C shows a misconception about exercise and appetite, indicating a potential misunderstanding of weight loss principles.
In summary, choice D is correct because it reflects a holistic approach to weight loss that includes addressing behavior patterns, while the other choices either focus on surface-level strategies or misunderstand key concepts related to weight loss.
Which of the following is true regarding the small intestine?
- A. It produces digestive enzymes
- B. It absorbs nutrients
- C. It produces bile
- D. It stores waste
Correct Answer: B
Rationale: The correct answer is B because the small intestine is primarily responsible for absorbing nutrients from digested food. It has specialized structures like villi to maximize nutrient absorption. Choice A is incorrect as the pancreas and other organs produce digestive enzymes. Choice C is incorrect as the liver produces bile. Choice D is incorrect as waste is stored in the large intestine, not the small intestine.
Salivary secretion:
- A. Starts digestion of carbohydrates.
- B. is under control of secretin hormone.
- C. Starts digestion of proteins.
- D. is highly acidic.
Correct Answer: A
Rationale: The correct answer is A because salivary secretion contains enzymes like amylase that start the digestion of carbohydrates in the mouth. This enzyme breaks down complex carbohydrates into simpler sugars. Choices B, C, and D are incorrect because salivary secretion is not directly controlled by secretin hormone, does not start the digestion of proteins, and is not highly acidic. Salivary secretion primarily aids in the initial breakdown of carbohydrates, preparing them for further digestion in the stomach and intestines.
Which of the following mechanisms most accurately describes how pseudo-membranous colitis caused by Clostridium difficile is produced?
- A. elaboration of an enterotoxin following colonization of the colon
- B. ingestion of a preformed toxin
- C. invasion and destruction of mucosa by the organism
- D. host immune response to the organism
Correct Answer: A
Rationale: The correct answer is A because Clostridium difficile produces toxins, specifically enterotoxins, which cause damage to the intestinal mucosa leading to pseudo-membranous colitis. The organism colonizes the colon and then elaborates the toxins, which disrupt the mucosal barrier.
Choice B is incorrect as there is no preformed toxin ingested; the toxin is produced by the organism after colonization. Choice C is incorrect as Clostridium difficile does not invade and destroy the mucosa directly. Choice D is incorrect as the host immune response is a consequence of the toxin production, not the primary mechanism of disease.