Nokea
Fick's law of diffusion is related to
- A. Diffusion and Surface area
- B. Diffusion and membrane potential
- C. Diffusion and water content
- D. Diffusion and pore diameter
Correct Answer: A
Rationale: Fick's law of diffusion states that the rate of diffusion is directly proportional to the surface area and concentration gradient, and inversely proportional to the distance over which diffusion occurs. Therefore, Choice A - Diffusion and Surface area is correct because surface area directly affects the rate of diffusion. Choices B, C, and D are incorrect as they do not directly relate to Fick's law. B is incorrect as membrane potential is not a factor in Fick's law. C is incorrect as water content is not a key factor in the law of diffusion. D is incorrect as pore diameter is not explicitly mentioned in Fick's law.
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Which of the following statements is false?
- A. Hemoglobin functions as a buffer
- B. Bicarbonate ions tend to diffuse out of red blood cells into the blood plasma.
- C. The movement of molecules is in different directions in the metabolically active tissues and the alveoli.
- D. Carbonic anhydrase is an enzyme that promotes the formation of oxyhemoglobin.
Correct Answer: D
Rationale: The correct answer is D because carbonic anhydrase catalyzes the conversion of carbon dioxide and water into bicarbonate ions and protons, not the formation of oxyhemoglobin. Step-by-step rationale: 1. Hemoglobin functions as a buffer by binding to hydrogen ions to help regulate pH levels in the blood. 2. Bicarbonate ions do tend to diffuse out of red blood cells into the plasma to maintain the balance of CO2 and pH. 3. The movement of molecules is indeed different in metabolically active tissues (where oxygen is released and CO2 is taken up) compared to the alveoli (where the opposite occurs). Therefore, choices A, B, and C are all correct statements, making D the false statement.
The last mammalian structure that air moves through before the alveoli is the
- A. larynx.
- B. glottis.
- C. bronchioles.
- D. trachea.
Correct Answer: C
Rationale: The correct answer is C: bronchioles. After air passes through the trachea, it enters the bronchi, which further divide into bronchioles. The bronchioles are the last structures where air passes before reaching the alveoli for gas exchange. The larynx is involved in sound production and the glottis is the opening between the vocal cords in the larynx. While the trachea is the initial passage for air into the respiratory system, the bronchioles are the final branching structures where air reaches the alveoli, making them the correct answer.
A nurse is working in a walk-in clinic. She has been alerted that there is an outbreak of tuberculosis (TB). Which of the following clients entering the clinic today is most likely to have TB?
- A. A 16-year-old female high school student
- B. A 33-year-old day-care worker.
- C. A 43-year-old homeless man with a history of alcoholism.
- D. A 54-year-old businessman.
Correct Answer: C
Rationale: The correct answer is C, a 43-year-old homeless man with a history of alcoholism. This choice is most likely to have TB because individuals who are homeless and have a history of alcoholism are at higher risk for TB due to weakened immune systems and living conditions. Homelessness and alcoholism increase the likelihood of exposure to TB.
Explanation for other choices:
A: A 16-year-old female high school student - Less likely to have TB compared to homeless individuals with risk factors.
B: A 33-year-old day-care worker - Possible but less likely compared to the homeless man with a history of alcoholism.
D: A 54-year-old businessman - Least likely to have TB compared to the homeless individual with risk factors.
Which of these factors does not affect hemoglobin's affinity for oxygen?
- A. RBC metabolic activity
- B. temperature
- C. electrolyte balance
- D. the PO2 of blood
Correct Answer: C
Rationale: The correct answer is C: electrolyte balance. Hemoglobin's affinity for oxygen is primarily influenced by factors such as pH, temperature, and the partial pressure of oxygen (PO2). Electrolyte balance, on the other hand, does not directly impact hemoglobin's ability to bind with oxygen. Changes in electrolyte levels may affect overall blood composition but do not directly alter hemoglobin's oxygen-binding capacity. Therefore, electrolyte balance does not affect hemoglobin's affinity for oxygen, making it the correct choice. RBC metabolic activity can impact oxygen release from hemoglobin, temperature can affect hemoglobin's oxygen-binding capacity, and the PO2 of blood directly influences oxygen binding to hemoglobin.
A male client comes to the emergency department complaining of sudden onset of diarrhea, anorexia, malaise, cough, headache, and recurrent chills. Based on the client's history and physical findings, the physician suspects Legionnaires' disease. While awaiting diagnostic test results, the client is admitted to the facility and started on antibiotic therapy. What is the drug of choice for treating Legionnaires' disease?
- A. erythromycin (Erythrocin)
- B. rifampin (Rifadin)
- C. amantadine (Symmetrel)
- D. amphotericin B (Fungizone)
Correct Answer: A
Rationale: The correct answer is A: erythromycin (Erythrocin). Legionnaires' disease is caused by the bacterium Legionella pneumophila, and erythromycin is the drug of choice for treating this infection. Erythromycin is a macrolide antibiotic that effectively targets Legionella bacteria by inhibiting their protein synthesis. It is bacteriostatic at low concentrations and bactericidal at higher concentrations. Rifampin (B) is not the preferred choice for Legionnaires' disease. Amantadine (C) is used for treating influenza A virus, not Legionella bacteria. Amphotericin B (D) is an antifungal agent and is not effective against Legionella pneumophila. Utilizing erythromycin as the treatment of choice ensures successful eradication of the Legionella bacteria and helps the client recover from the infection.