ATI LPN
Exam Questions on Respiratory System Questions
Question 1 of 5
Which of the following structures contains blood with the highest PCO2?
Correct Answer: C
Rationale: Superior vena cava (C) carries deoxygenated blood with high PCO2 (~46 mmHg) from tissues. Pulmonary veins (B) have low PCO2 (~40 mmHg) post-exchange. Systemic arterioles (D) match arterial PCO2 (~40 mmHg). Carotid bodies (A) sense blood, not store it venous PCO2 exceeds arterial. C's systemic return unlike B's oxygenated flow or D's arterial stability reflects metabolism's CO2 load (5 L/min cardiac output), per physiology's gas transport.
Question 2 of 5
At the end of quiet respiration, muscles are relaxed and lungs content represents.
Correct Answer: C
Rationale: Post-quiet expiration, lungs are at FRC (~2.5 L) . Muscles relax, balancing lung inward and chest outward recoil (Q2). RV (A) is post-forced (~1.2 L). ERV (B) is reserve (~1.3 L). IRV (D) is inspiratory reserve (~3 L). FRC RV + ERV is resting volume, with intrapleural pressure -5 cm H2O, unlike A's minimal or D's inspiratory state, per physiology (Q17).
Question 3 of 5
The work of breathing is:
Correct Answer: A
Rationale: Work of breathing inversely ties to compliance. Work = pressure × volume; low compliance (e.g., fibrosis, < 0.1 L/cm H2O) demands more pressure (Q40). Exercise raises work (B, false) via demand (O2 use 1-5%). Resistance (C, false) increases it (asthma, Q8). Fibrosis hikes work (D, false, Q1). A's relation unlike B's static claim matches energy cost (~1-2% basal metabolism), per physiology.
Question 4 of 5
In acute diaphragmatic pleurisy involving the central part of the diaphragm, the patient is likely to complain of pain in:
Correct Answer: A
Rationale: Acute diaphragmatic pleurisy, inflammation of the pleural lining over the diaphragm's central portion, typically causes referred pain to the neck and shoulder (A) via the phrenic nerve (C3-C5), which innervates the diaphragm and shares dermatomes with the supraclavicular region. Lateral chest pain (B) aligns with parietal pleura irritation, not central diaphragmatic. Central chest pain (C) suggests mediastinal or cardiac issues, not diaphragmatic referral. Interscapular pain (D) lacks nerve linkage here, and right lower quadrant pain ties to abdominal pathology, not pleural. This referred pattern, distinct from local chest wall pain, is key in diagnosing diaphragmatic involvement e.g., in pneumonia or subphrenic abscess guiding imaging or intervention, a critical chest pain differentiation in clinical practice.
Question 5 of 5
A bloody pleural effusion is consistent with a diagnosis of which of the following:
Correct Answer: D
Rationale: A bloody pleural effusion aligns with pulmonary embolus (A) and myocardial infarct (C) thus D (A & C). Embolus causes infarction, leaking RBCs into pleura; post-MI (e.g., Dressler's) involves hemorrhagic inflammation. Acute hemorrhagic pancreatitis (B) causes abdominal effusion, rarely pleural, and not typically bloody unless complicated. All' overextends pancreatitis lacks direct pleural linkage. Bloody effusions (RBC >10,000/mm³) signal vascular or inflammatory breach, distinguishing from transudates, critical in differential diagnosis via thoracentesis, a chest nursing focus.