Nokea
In human beings, partial pressure of carbon dioxide in the inspired and expired air is respectively
- A. 0.3 and 40 mm Hg
- B. 0.3 and 32 mm Hg
- C. 40 and 46 mm Hg
- D. 40 and 0.3 mm Hg
Correct Answer: B
Rationale: The correct answer is B (0.3 and 32 mm Hg) because in inspired air, the partial pressure of carbon dioxide is low at around 0.3 mm Hg, whereas in expired air, the partial pressure of carbon dioxide is higher at around 32 mm Hg due to gas exchange in the lungs.
Choice A (0.3 and 40 mm Hg) is incorrect because the partial pressure of carbon dioxide in inspired air is not typically as high as 40 mm Hg.
Choice C (40 and 46 mm Hg) is incorrect because the values are reversed; the partial pressure of carbon dioxide is higher in expired air compared to inspired air.
Choice D (40 and 0.3 mm Hg) is incorrect as the values are reversed, and the partial pressure of carbon dioxide in inspired air is not typically as high as 40 mm Hg.
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pharynx is a muscular tube with a length of
- A. 13cm
- B. 12cm
- C. Sinches
- D. both a and c
Correct Answer: A
Rationale: The correct answer is A: 13cm. The human pharynx is typically around 13cm in length. This length allows for the proper passage of food and liquids from the mouth to the esophagus. Choice B (12cm) is incorrect as it is slightly shorter than the average length of the pharynx. Choice C (5 inches) is also incorrect as it does not correspond to the standard unit of measurement for medical lengths. Choice D (both a and c) is incorrect as 12cm and 5 inches are not equivalent lengths for the pharynx.
Pneumotaxic center is
- A. Inhibitory
- B. Accelatory
- C. Activating
- D. None of these
Correct Answer: A
Rationale: The correct answer is A: Inhibitory. The pneumotaxic center is located in the upper pons and functions to inhibit inspiration, preventing overinflation of the lungs. This helps regulate the respiratory rate and depth. The other choices are incorrect because the pneumotaxic center does not accelerate or activate breathing directly. It exerts its influence by inhibiting the inspiratory neurons in the medulla, thereby controlling the duration and frequency of inspiration. Choice D is incorrect as the pneumotaxic center does have a specific inhibitory function in the respiratory control system.
Carbonic anhydrase in the RBC is the fastest enzyme and it decomposes in one second for fast action. Its concentration in the blood is due to the presence of
- A. Plasma
- B. Carbon dioxide
- C. Sodium ions
- D. Hemoglobin
Correct Answer: D
Rationale: The correct answer is D: Hemoglobin. Carbonic anhydrase is an enzyme found in red blood cells that rapidly catalyzes the conversion of carbon dioxide into bicarbonate ions. Hemoglobin plays a crucial role in transporting carbon dioxide in the blood. The high concentration of hemoglobin in red blood cells allows for efficient binding and transport of carbon dioxide, leading to the need for a rapid enzyme like carbonic anhydrase to facilitate its conversion. Plasma (choice A) does not directly influence the concentration of carbonic anhydrase. Carbon dioxide (choice B) is the substrate for carbonic anhydrase, not the reason for its concentration. Sodium ions (choice C) do not directly affect the action of carbonic anhydrase in red blood cells.
Mammalian lungs have numerous alveoli for
- A. Increasing the volume of inspired air
- B. Keeping the lungs in proper shape
- C. Higher number of muscles to provide greater elasticity
- D. Increasing surface area for gaseous diffusion
Correct Answer: D
Rationale: The correct answer is D because alveoli increase the surface area for gaseous diffusion, facilitating efficient exchange of oxygen and carbon dioxide in the lungs. Alveoli are tiny air sacs where gas exchange occurs. Option A is incorrect as alveoli do not affect the volume of inspired air. Option B is incorrect as alveoli do not play a role in maintaining lung shape. Option C is incorrect as alveoli do not increase muscles in the lungs for elasticity. Therefore, the primary function of alveoli is to increase surface area for gaseous diffusion, making option D the correct choice.
A nurse cares for a client who had a bronchoscopy 2 hours ago. The client asks for a drink of water. Which action should the nurse take next?
- A. Call the physician and request a prescription for food and water.
- B. Provide the client with ice chips instead of a drink of water.
- C. Assess the client's gag reflex before giving any food or water.
- D. Let the client have a small sip to see whether he or she can swallow.
Correct Answer: C
Rationale: Correct Answer: C
Rationale:
1. Assessing the client's gag reflex is crucial after a bronchoscopy to prevent aspiration.
2. Gag reflex helps protect the airway from foreign substances entering the lungs.
3. Providing food or water without assessing the gag reflex can lead to aspiration pneumonia.
4. It is essential to ensure the client's safety before allowing any intake post-bronchoscopy.
Summary:
A: Calling the physician for a prescription is not necessary at this immediate stage.
B: Ice chips may still pose a risk if the client cannot protect their airway.
D: Allowing a sip without assessing gag reflex may lead to aspiration.