Nokea
Respiratory mechanism is controlled by
- A. Central nervous system
- B. Sympathetic nervous system
- C. Parasympathetic nervous system
- D. Autonomic nervous system
Correct Answer: A
Rationale: The correct answer is A: Central nervous system. The respiratory mechanism is controlled by the brainstem, specifically the medulla oblongata and pons. These areas of the central nervous system regulate breathing by monitoring levels of carbon dioxide and oxygen in the blood. The medulla sets the basic rhythm of breathing, while the pons helps fine-tune the breathing rate. Choices B, C, and D are incorrect because while the sympathetic and parasympathetic nervous systems are involved in regulating various bodily functions, they do not directly control the respiratory mechanism. The autonomic nervous system, which includes both the sympathetic and parasympathetic divisions, plays a role in involuntary functions like heart rate and digestion, but it is not the primary controller of breathing.
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Which of the following are risk factors of laryngeal cancer?
- A. Acute laryngitis
- B. Tobacco use
- C. Caffeine use
- D. Sleep apnea
Correct Answer: B
Rationale: The correct answer is B. Tobacco use is a well-established risk factor for laryngeal cancer. A (acute laryngitis) is a temporary condition and not a risk factor. C (caffeine use) has no proven link to laryngeal cancer. D (sleep apnea) is unrelated.
When CO2 diffuses into blood in systemic capillaries most of it:
- A. Remains in solution as CO2
- B. Converts to carbamino compounds
- C. Converts to bicarbonate ions in RBC
- D. Combines with Hb directly
Correct Answer: C
Rationale: The correct answer is C because the majority of CO2 diffusing into blood combines with water inside red blood cells (RBC) to form carbonic acid, which then dissociates into bicarbonate ions and hydrogen ions. This reaction is facilitated by the enzyme carbonic anhydrase. This process allows for efficient transport of CO2 in the bloodstream. Choices A and B are incorrect as CO2 primarily undergoes conversion to bicarbonate ions, not remaining in solution as CO2 or forming carbamino compounds. Option D is incorrect as CO2 does not directly combine with hemoglobin.
Carbon monoxide
- A. has a very low affinity or attraction to hemoglobin.
- B. is unlikely to be transported by the circulatory system.
- C. is not the cause of death of people who breathe excessive amounts of automobile exhausts.
- D. can arise from cigarette smoke
Correct Answer: D
Rationale: The correct answer is D because carbon monoxide can indeed arise from cigarette smoke due to incomplete combustion of tobacco. This is supported by scientific evidence. Carbon monoxide has a high affinity for hemoglobin, so choice A is incorrect. It can be transported by the circulatory system, making choice B incorrect. Breathing excessive amounts of automobile exhaust containing carbon monoxide can lead to death, making choice C incorrect.
A nurse has educated a client on isoniazid. What statement by the client indicates that teaching has been effective?
- A. I need to take extra vitamin C while on isoniazid.
- B. I should take this medicine with milk or juice.
- C. I will take this medication on an empty stomach.
- D. My contact lenses will be permanently stained.
Correct Answer: C
Rationale: The correct answer is C: "I will take this medication on an empty stomach." This indicates effective teaching because isoniazid should be taken on an empty stomach to maximize absorption. Taking it with food can reduce absorption.
A: Taking extra vitamin C is not necessary for isoniazid.
B: Taking isoniazid with milk or juice can reduce its effectiveness.
D: Contact lenses are not affected by isoniazid, so they will not be permanently stained.
For the surface of an animal to function in the integumentary exchange of gases it must
- A. be thin and soft.
- B. have a high number of blood vessels
- C. have mucus or moist covering
- D. all of the above
Correct Answer: D
Rationale: The correct answer is D because for the integumentary exchange of gases to occur efficiently, the surface of the animal must meet all three criteria: be thin and soft to allow gases to pass through easily, have a high number of blood vessels to facilitate gas exchange, and have a mucus or moist covering to prevent desiccation and aid in gas diffusion. If the surface is not thin and soft, gases cannot diffuse effectively. Without a high number of blood vessels, there wouldn't be sufficient transport of gases to and from the surface. And without a mucus or moist covering, the surface may dry out, hindering gas exchange. Therefore, all of the above factors are essential for the integumentary exchange of gases to function optimally.