ATI LPN
Respiratory System Practice Questions Questions
Question 1 of 5
The maximum volume of air contained in the lung by a full forced inhalation is called _________.
Correct Answer: D
Rationale: Total lung capacity (TLC) is the maximum air volume the lungs hold after a full forced inhalation, about 6 liters in adults, encompassing all lung volumes (tidal, inspiratory reserve, expiratory reserve, and residual). Tidal volume is normal breathing (~500 mL), not maximum. Vital capacity is maximal inhalable/exhalable air (~4.8 L), excluding residual volume, less than TLC. Ventilation rate is breaths per minute, not volume. TLC reflects lung health reduced in restrictive diseases like fibrosis measuring total potential, critical in pulmonary function tests to assess capacity and guide respiratory therapy.
Question 2 of 5
Identify the structure found in a fetus that allows blood to flow directly from the pulmonary trunk into the aorta.
Correct Answer: D
Rationale: The ductus arteriosus, a fetal vessel, shunts blood from the pulmonary trunk to the aorta, bypassing nonfunctional lungs oxygen comes from the placenta. The fossa ovalis is a postnatal remnant of the foramen ovale, which shunts atrial blood. Trabeculae carneae are ventricular ridges, not shunts. This temporary conduit closes after birth (ligamentum arteriosum), redirecting blood to the lungs, a key fetal adaptation ensuring systemic oxygenation, critical in congenital defects like patent ductus arteriosus where closure fails.
Question 3 of 5
The volume of blood ejected from the left ventricle into the aorta each minute is called the
Correct Answer: A
Rationale: Cardiac output (CO) is the volume of blood the left ventricle ejects into the aorta per minute, typically 5-6 liters at rest, calculated as stroke volume (blood per beat) times heart rate. 'Cardiac input' isn't a standard term venous return approximates it. Stroke volume is per beat (~70 mL), not minute. Heart rate is beats per minute, not volume. CO measures heart efficiency, key in assessing circulation and diagnosing failure where output drops, a vital metric in cardiovascular physiology and clinical monitoring.
Question 4 of 5
The difference between a person's maximum cardiac output and resting cardiac output is called the
Correct Answer: D
Rationale: Cardiac reserve is the difference between maximum cardiac output (e.g., during exercise, ~20 L/min) and resting CO (~5 L/min), reflecting the heart's capacity to increase pumping. Stroke volume is per beat. Peripheral resistance is vascular opposition, not output. Afterload is arterial pressure resisted. Reserve, boosted by rate and contractility, gauges heart health, key in fitness and failure where it diminishes, a vital performance indicator.
Question 5 of 5
The muscular layer of the heart wall is the:
Correct Answer: C
Rationale: The myocardium is the heart wall's muscular layer, cardiac muscle with intercalated discs for synchronized contraction, pumping blood. Epicardium (outer) and endocardium (inner) are connective; pericardium is the external sac. This layer's thickness and strength, especially left-sided, drive heart action, key in physiology and failure where muscle weakens, a definitive cardiac component.