Nokea
What physiologic role does calcium play in the body?
- A. Blood clotting, transmission of nerve impulses, muscle contraction and relaxation
- B. Calcium homeostasis, structural integrity of heart muscle
- C. No known metabolic function, caries-preventing properties
- D. ATP energy release; metabolism of fats, carbohydrates, proteins; regulates acid-base balance.
Correct Answer: A
Rationale: The correct answer is A: 'Blood clotting, transmission of nerve impulses, muscle contraction and relaxation.' Calcium plays a crucial role in various physiological functions such as blood clotting, transmission of nerve impulses, muscle contraction and relaxation, membrane permeability, and activation of certain enzymes. Choice B is incorrect because while calcium is involved in calcium homeostasis, it is not the only role it plays in the body. Choice C is incorrect as calcium indeed has several known metabolic functions, and it is not solely for preventing caries. Choice D is also incorrect as the functions mentioned are primarily carried out by other nutrients and not specifically by calcium.
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Each is a physiologic role of vitamin D, except one. Which is the exception?
- A. Hematopoiesis
- B. Cardiac and neuromuscular function
- C. Immune responses
- D. Serum calcium regulation
Correct Answer: A
Rationale: The correct answer is A, Hematopoiesis. Vitamin D plays a crucial role in regulating serum calcium levels, which is essential for maintaining cardiac and neuromuscular function. Additionally, vitamin D is involved in modulating immune responses. However, hematopoiesis, the formation of red blood cells, is not a direct physiologic role of vitamin D. Therefore, hematopoiesis is the exception among the listed functions of vitamin D.
Each statement is true of water-soluble vitamins, except one. Which is it?
- A. Act as coenzymes
- B. Deficiencies develop rapidly
- C. Daily intake is necessary
- D. Absorbed in the jejunum
Correct Answer: B
Rationale: The correct answer is B. Water-soluble vitamins do not develop deficiencies rapidly because the body does not store them for long periods. They must be obtained through food constantly. Choice A is correct because water-soluble vitamins often act as coenzymes in various metabolic reactions. Choice C is correct as daily intake of water-soluble vitamins is necessary since they are not stored in the body. Choice D is incorrect as water-soluble vitamins are absorbed primarily in the small intestine, particularly in the duodenum and ileum, not the jejunum.
How is the equalization of solute concentration of intracellular fluids (ICFs) and extracellular fluids (ECFs accomplished?
- A. Semipermeable membranes.
- B. Hydration.
- C. Osmotic pressure.
- D. Perspiration.
Correct Answer: C
Rationale: The correct answer is C, osmotic pressure. Osmotic pressure within the body equalizes the solute concentration of ICFs and ECFs by shifting small amounts of water in the direction of higher concentration solute. Semipermeable membranes separate one fluid compartment from another and do not directly equalize solute concentrations. Hydration and perspiration are important elements of fluid balance but do not directly achieve the equalization of solute concentrations between ICFs and ECFs, which is primarily regulated by osmotic pressure.
Scurvy is caused by a deficiency of which vitamin?
- A. Vitamin A
- B. Vitamin D
- C. Vitamin E
- D. Vitamin K
Correct Answer: C
Rationale: Scurvy is caused by a deficiency of vitamin C, not vitamin E. The symptoms of scurvy include spontaneous gingival hemorrhaging, perifollicular petechiae, follicular hyperkeratosis, diarrhea, fatigue, depression, and cessation of bone growth. Vitamin A (Choice A) is important for vision and immune function, Vitamin D (Choice B) is essential for bone health, and Vitamin K (Choice D) is necessary for blood clotting. However, none of these vitamins are associated with scurvy.
The oral cavity is the site of a wide variety of systemic disease manifestations due to:
- A. Rapid cellular turnover
- B. Constant attack by microorganisms
- C. Trauma-intense environment
- D. All of the above
Correct Answer: D
Rationale: The oral cavity is indeed the site of various systemic disease manifestations due to multiple factors. Firstly, the rapid cellular turnover in the oral mucosa makes it susceptible to diseases. Secondly, the constant presence of microorganisms in the oral cavity contributes to the development of systemic diseases. Finally, the oral cavity being a trauma-intense environment further increases the risk of systemic manifestations. Therefore, all the provided options - rapid cellular turnover, constant attack by microorganisms, and a trauma-intense environment - play a role in making the oral cavity a site for various systemic diseases. Hence, the correct answer is 'All of the above.' Choices A, B, and C are incorrect individually as they each represent only one aspect of why the oral cavity is prone to systemic disease manifestations, whereas the correct answer encompasses all these factors.