ATI LPN
NCLEX PN Questions Respiratory System Questions
Question 1 of 5
Which of the following are parts of the human respiratory system?
Correct Answer: D
Rationale: The human respiratory system includes the trachea, diaphragm, and lungs, all integral to breathing. The trachea, or windpipe, channels air to the lungs, lined with cilia to filter debris. The diaphragm, a dome-shaped muscle, contracts to expand the chest, driving inhalation its relaxation aids exhalation. The lungs house alveoli for gas exchange, the system's endpoint. Each part contributes: trachea as conduit, diaphragm as pump, lungs as exchange site. Excluding any would overlook their coordinated role in oxygenating blood and expelling CO2, a holistic view essential for understanding respiration's mechanics and clinical interventions like ventilatory support.
Question 2 of 5
Which layer of the heart wall consists of mesothelium and connective tissue?
Correct Answer: A
Rationale: The epicardium, the heart wall's outer layer (visceral pericardium), comprises mesothelium (a simple squamous epithelium) and underlying connective tissue, providing a smooth, protective surface with coronary vessels. The myocardium is cardiac muscle, driving contraction, not mesothelium-based. The endocardium, the inner lining, is endothelium and connective tissue but distinct from the outer epicardium. The fibrous pericardium is dense connective tissue, lacking mesothelium. The epicardium's structure reduces friction with the pericardial sac and supports vascular supply, a key layer in heart anatomy, critical in conditions like epicarditis affecting this surface.
Question 3 of 5
What of the following chambers of the heart contain deoxygenated blood?
Correct Answer: C
Rationale: The right atrium and right ventricle contain deoxygenated blood, received from systemic veins (vena cavae) into the atrium, then pumped via the ventricle to the lungs for oxygenation. The left atrium and ventricle hold oxygenated blood from pulmonary veins, destined for the body. 'Left atrium only' or 'right ventricle only' ignores paired chamber roles. This right-side deoxygenation reflects the heart's dual circulation systemic and pulmonary a fundamental division ensuring oxygen delivery, critical in understanding cardiac flow and congenital defects mixing these streams.
Question 4 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 5 of 5
Heart murmurs are often heard in individuals with abnormalities in the _____ of the heart.
Correct Answer: A
Rationale: Heart murmurs stem from valve abnormalities stenosis (narrowing) or regurgitation (leakage) disrupting smooth blood flow, causing turbulence audible as whooshes. Myocardium issues (e.g., infarction) affect contraction, not murmurs directly. SA/AV node problems alter rhythm, not flow sounds. Valves (tricuspid, mitral, pulmonary, aortic) regulate direction; defects like mitral prolapse create murmurs, key in diagnosis via auscultation, distinguishing benign from pathological flow disruptions.