Nokea
Identify the inconsistent value in these measurements on a mixed venous blood sample obtained in a healthy person from IVC at sea level
- A. pO2 = 40mmHg
- B. pCO2 = 48mmHg
- C. PN2 = 620mmHg
- D. O2 content = 150ml/L blood
Correct Answer: C
Rationale: The correct answer is C: PN2 = 620mmHg. This is the inconsistent value because the normal partial pressure of nitrogen in venous blood is around 40 mmHg, not 620 mmHg. This discrepancy indicates an abnormal measurement. The other choices (A, B, D) are within expected ranges for a mixed venous blood sample in a healthy person at sea level. Choice A (pO2 = 40mmHg) is typical for venous blood, choice B (pCO2 = 48mmHg) falls within the normal range, and choice D (O2 content = 150ml/L blood) is a reasonable value for mixed venous blood.
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Most of the carbon dioxide in the blood is transported as
- A. solute dissolved in the plasma
- B. carbaminohemoglobin
- C. bicarbonate ions
- D. solute dissolved in the cytoplasm of red blood cells
Correct Answer: C
Rationale: The correct answer is C: bicarbonate ions. Carbon dioxide in the blood mainly combines with water to form carbonic acid, which dissociates into bicarbonate ions and hydrogen ions. The majority of carbon dioxide is transported in the blood as bicarbonate ions. This process occurs in red blood cells via the enzyme carbonic anhydrase. Choices A and D are incorrect as carbon dioxide mainly combines with water and does not remain as a solute in plasma or cytoplasm. Choice B, carbaminohemoglobin, is a minor way carbon dioxide is transported, where a small amount binds to hemoglobin, but the majority is transported as bicarbonate ions.
Which muscle(s) produce(s) the movement labeled '1'?
- A. rectus abdominis
- B. internal intercostals
- C. external intercostals
- D. diaphragm
Correct Answer: C
Rationale: The correct answer is C: external intercostals. These muscles are responsible for elevating the ribcage during inhalation, which corresponds to the movement labeled '1'. The rectus abdominis (A) is involved in trunk flexion, internal intercostals (B) aid in forced exhalation, and the diaphragm (D) primarily assists in inhalation by moving downward to increase thoracic cavity volume. Therefore, the external intercostals are the correct choice for the specific movement indicated in the question.
Damage to the phrenic nerves would
- A. increase respiratory rate
- B. increase the tidal volume
- C. force reliance on costal breathing
- D. result in greater pressure differences between the lungs and the outside air
Correct Answer: C
Rationale: Damage to the phrenic nerves would result in the inability to fully expand the diaphragm, leading to reliance on costal breathing. This is because the phrenic nerves innervate the diaphragm, the main muscle of respiration. Without proper diaphragmatic function, the individual would have difficulty engaging in effective diaphragmatic breathing. Therefore, choice C is correct.
Choices A, B, and D are incorrect because damage to the phrenic nerves would not directly impact the respiratory rate, tidal volume, or pressure differences between the lungs and the outside air. These functions are more related to overall respiratory control and lung mechanics, which are not solely dependent on the phrenic nerves.
The exchange of gases between blood and cells is called
- A. pulmonary ventilation
- B. internal respiration
- C. external respiration
- D. cellular respiration
Correct Answer: B
Rationale: The correct answer is B: internal respiration. This process refers to the exchange of gases between blood and body cells. Pulmonary ventilation (A) is the process of breathing, moving air in and out of the lungs. External respiration (C) is the exchange of gases between the lungs and blood. Cellular respiration (D) is the process where cells use oxygen to produce energy. Internal respiration best describes the exchange of gases at the cellular level.
Aminophylline (theophylline) is prescribed for a client with acute bronchitis. A nurse administers the medication, knowing that the primary action of this medication is to?
- A. Promote expectoration.
- B. Suppress the cough.
- C. Relax smooth muscles of the bronchial airway.
- D. Prevent infection.
Correct Answer: C
Rationale: The correct answer is C: Relax smooth muscles of the bronchial airway. Aminophylline (theophylline) is a bronchodilator that works by relaxing the smooth muscles in the bronchial airways, which helps to open up the airways and improve airflow. This action helps to relieve bronchospasm, which is common in conditions like acute bronchitis. Promoting expectoration (A) and suppressing cough (B) are not the primary actions of aminophylline, although they may be secondary effects. Preventing infection (D) is unrelated to the mechanism of action of aminophylline in treating acute bronchitis.