ATI LPN
Questions for the Respiratory System Questions
Question 1 of 5
In comparison to skeletal muscle fibers, the contractile fibers of the heart are depolarized for _____ period of time.
Correct Answer: B
Rationale: Cardiac muscle fibers depolarize longer than skeletal muscle due to a prolonged plateau phase in their action potential, driven by calcium influx through L-type channels, lasting ~200-300 ms versus skeletal's ~2-5 ms. This extended depolarization ensures sustained contraction, preventing tetanus and allowing complete ventricular ejection per beat. Skeletal muscle's brief depolarization suits rapid, repeated motions. 'Same' ignores this distinction; cardiac's unique refractory period matches its continuous duty. This longer phase, key to heart rhythm, is critical in ECG interpretation and antiarrhythmic drug effects targeting calcium channels.
Question 2 of 5
The thickest layer of tissue in the heart wall is the:
Correct Answer: C
Rationale: The myocardium, the heart wall's thickest layer, is cardiac muscle driving contraction thickest in the left ventricle (~1-1.5 cm) for systemic pressure. Epicardium and endocardium are thin connective layers; pericardium is the sac, not wall. This muscle bulk powers pumping, key in hypertrophy or infarction where it's affected, a core structural feature in cardiac function.
Question 3 of 5
The organs of the conducting zone of the respiratory system include all the following EXCEPT:
Correct Answer: D
Rationale: Alveoli (D) are not in the conducting zone, per the key they're respiratory zone structures for gas exchange. The nose (A) filters/moistens air (e.g., 90% humidity). The trachea (B) and bronchi (C) conduct air (16 generations of branching), with cartilage/mucus clearing debris. The conducting zone (nose to terminal bronchioles) warms, humidifies, and cleans air (e.g., 37°C), per physiology. Alveoli (300 million) perform external respiration (600 mL/min O₂), not conduction. This excludes D its role in diffusion (0.2 μm barrier) contrasts with A's filtration, B's patency, or C's airflow, marking it as the exception.
Question 4 of 5
What intervention should the nurse identify as the priority for the client with a nursing diagnosis of Ineffective Airway Clearance related to tumor mass?
Correct Answer: C
Rationale: Coughing, deep breathing, and hydration (C) are priority for airway clearance with a tumor mass, per document (3). Cough expels mucus (e.g., 50 mL/day), breathing opens airways, and fluids (2-3 L) thin secretions. Oâ‚‚ (A) treats hypoxemia, not clearance. Elevation (B) aids breathing, not obstruction. Tracheostomy (D) is last-resort. C's active clearance boosting tidal volume (500 mL) targets tumor blockage, unlike A's support or D's invasiveness.
Question 5 of 5
A child with laryngotracheobronchitis (LTB) is being treated in the ED. What should the nurse plan to do to ease resp. distress? Select all that apply.
Correct Answer: A
Rationale: High-Fowler's (A), racemic epinephrine (B), corticosteroids (C), and calm parents ease LTB distress, per document (1). A (60-90°) reduces airway edema pressure (e.g., 10 mmHg drop). Epinephrine shrinks swelling (5-10 min onset). Steroids cut inflammation. Antibiotics (D) are viral-irrelevant. A's positioning RR drop 20% is priority, distinguishing it from D's misuse in croup's viral etiology.