ATI LPN
NCLEX PN Questions on Respiratory System Questions
Question 1 of 5
The outermost layer of the pericardium, which consists of inelastic dense irregular connective tissue, is called the
Correct Answer: C
Rationale: The fibrous pericardium, the pericardium's outermost layer, is inelastic dense irregular connective tissue, anchoring the heart to the diaphragm and sternum, preventing overstretch. The parietal layer is serous, lining the fibrous part, not the outer tissue. Serous pericardium includes parietal and visceral (epicardium) layers, both thin and lubricative. The epicardium is the heart's surface, not pericardial. This tough fibrous layer's protective rigidity contrasts with the serous layers' fluidity, a structural balance critical for heart stability, key in understanding pericardial anatomy and conditions like constrictive pericarditis.
Question 2 of 5
During which of the following periods does the largest volume of blood enter the arteries?
Correct Answer: D
Rationale: Ventricular systole is when the largest blood volume enters the arteries left ventricle into the aorta, right into the pulmonary trunk as contraction ejects stroke volume (~70 mL/beat). Atrial diastole fills atria, not arteries. Ventricular diastole fills ventricles, not direct artery entry. Atrial systole adds to ventricular filling (~20-30% of volume), not artery flow. Systole's forceful push, timed with semilunar valve opening, maximizes arterial delivery, key to systemic and pulmonary circulation, a pivotal phase in cardiac output and pressure wave generation.
Question 3 of 5
Isovolumetric contraction is the phase of the cardiac cardiac cycle in which
Correct Answer: D
Rationale: Isovolumetric contraction, early ventricular systole, sees pressure rise as myocardium contracts, but volume stays constant all valves (AV, semilunar) are closed, no blood enters or exits. Semilunar valves open later (ejection). Repolarization is post-systole. Atrial depolarization precedes this. This brief phase (~50 ms) builds pressure to exceed arterial levels, key in cycle timing, critical in heart sound analysis and dysfunction where pressure fails to rise adequately.
Question 4 of 5
The right atrioventricular valve is also called the:
Correct Answer: B
Rationale: The right atrioventricular (AV) valve is the tricuspid, with three cusps, preventing backflow from right ventricle to atrium. Bicuspid and mitral are left-sided (same valve); aortic is semilunar, not AV. This naming reflects its tri-leaflet design, key in right heart flow, critical in tricuspid issues like regurgitation, a precise valve identity.
Question 5 of 5
The organ of the respiratory system that closes when food is being swallowed is the:
Correct Answer: C
Rationale: The larynx (C) closes during swallowing, per the key the epiglottis seals the glottis, preventing aspiration. The nose (A) stays open (no closure mechanism). The pharynx (B) conducts food/air but doesn't close. The trachea (D) remains patent (cartilage rings). Swallowing's pharyngeal phase (0.5 s) tilts the epiglottis via hyoid movement, per anatomy laryngeal closure protects lungs (e.g., 1-2 L food/day diverted). This distinguishes C from A's irrelevance, B's conduit role, or D's openness the larynx's gatekeeping is unique.