ATI LPN
NCLEX PN Questions Respiratory System Questions
Question 1 of 5
Which structure in the heart initiates action potentials that stimulate contraction of the heart at constant rate of about 100 beats per minute?
Correct Answer: D
Rationale: The sinoatrial (SA) node initiates action potentials, pacing the heart at ~100 beats per minute intrinsically, though nerves adjust this to ~70 bpm normally. Located in the right atrium, it's the natural pacemaker, firing spontaneously via pacemaker cells' ion shifts. Cardiac accelerator nerves (sympathetic) speed it up, not initiate. The AV node delays signals, not starts them (~40-60 bpm if SA fails). The cardiovascular center in the medulla modulates rate, not generates. The SA node's primacy ensures rhythm, key in physiology and arrhythmias like sinus tachycardia where its rate shifts.
Question 2 of 5
The chamber of the heart that normally has the thickest wall is the:
Correct Answer: D
Rationale: The left ventricle has the thickest wall (~1-1.5 cm), its myocardium pumping against systemic pressure (~120 mmHg), far exceeding right ventricle (~0.3-0.5 cm, ~25 mmHg pulmonary) or atria (~0.1-0.2 cm). This thickness meets workload, key in hypertrophy or failure, a fundamental adaptation in cardiac anatomy and function.
Question 3 of 5
The organ of the respiratory system that traps bacteria with a ring of tonsils is the:
Correct Answer: B
Rationale: The pharynx (B) traps bacteria with tonsils (e.g., palatine, adenoids), per the key lymphoid tissue filters pathogens (e.g., 10ⶠbacteria/day). The nose (A) uses mucus/hairs, not tonsils. The larynx (C) and trachea (D) lack tonsils mucus alone clears debris. Pharyngeal tonsils (Waldeyer's ring) produce lymphocytes, per immunology, guarding against inhaled/oral microbes unlike A's physical trap, C's vocal role, or D's conduit function, B's immune barrier is distinct.
Question 4 of 5
A client underwent a thoracentesis a few hours earlier. Which finding should the nurse report immediately to explain why dyspnea occurs?
Correct Answer: B
Rationale: Onset of crepitus (B) post-thoracentesis signals subcutaneous emphysema air in tissues (e.g., 50-100 mL) from pleural breach, causing dyspnea (RR >25), per document (2). Oozing (A) is minor, not dyspnea-linked. Diminished sounds (C) suggest pneumothorax, less urgent unless tension. Fever (D) is infection, not immediate. B's air trapping palpable crunch compromises breathing, distinguishing it from A's bleeding or C's collapse.
Question 5 of 5
If treatment for acute epiglottitis is effective, what should the nurse expect to record about the child?
Correct Answer: D
Rationale: Clear bilateral breath sounds (D) show effective epiglottitis treatment, per document (4). Antibiotics (e.g., ceftriaxone) and steroids resolve swelling (e.g., 24-48 hr), restoring airflow (RR <30). Pale lips (A) or tripod (B) persist pre-treatment. Tachypnea (C) lingers if unresolved. D's clarity normal vesicular sounds confirms recovery, unlike A's hypoxia sign.