ATI LPN
Respiratory System Questions Questions
Question 1 of 5
Identify the pouch-like structure that increases the total filling capacity of the atrium.
Correct Answer: D
Rationale: The auricle, a pouch-like extension of the atrium, increases its filling capacity, allowing more blood storage during diastole, enhancing atrial volume. The ventricle pumps blood, not a storage pouch. The coronary sulcus is a groove for coronary vessels, not a capacity structure. The fossa ovalis, a fetal remnant, doesn't affect volume. Auricles, wrinkled and ear-like, expand atrial space, aiding preload more prominent on the left crucial for optimizing cardiac output, a subtle but significant feature in heart anatomy and function assessment.
Question 2 of 5
Stimulation of which nerve reduces heart rate?
Correct Answer: D
Rationale: The vagus nerve (cranial nerve X), via parasympathetic fibers, reduces heart rate by releasing acetylcholine, slowing SA node firing and AV conduction, dropping beats from ~100 to ~70 bpm at rest. Cardiac accelerator nerves (sympathetic) increase rate. The hypoglossal nerve controls tongue movement, not heart. The spinal accessory nerve moves neck muscles, irrelevant here. Vagal stimulation, part of the 'rest and digest' response, balances sympathetic drive, a key autonomic regulator, critical in bradycardia and vagal maneuvers to slow tachycardias.
Question 3 of 5
In comparison to a sedentary individual, a well-trained athlete will usually have all the following characteristics EXCEPT
Correct Answer: B
Rationale: A well-trained athlete has higher cardiac reserve (max CO increase), stroke volume (more blood per beat), and heart hypertrophy (thicker myocardium) due to endurance training, enhancing efficiency. Resting cardiac output (~5 L/min) remains similar to sedentary individuals athletes' lower resting heart rate (bradycardia, e.g., 40-60 bpm) offsets higher SV, balancing CO. Higher resting CO isn't typical; demand matches supply. This adaptation optimizes performance, key in sports physiology and assessing training effects.
Question 4 of 5
The valve that guards the left atrioventricular orifice is called the:
Correct Answer: D
Rationale: The left atrioventricular valve is called both bicuspid (two cusps) and mitral (mitre-shaped), guarding the left atrium-ventricle junction, preventing backflow. Tricuspid is right-sided. This dual naming reflects its structure and role, key in mitral pathology like prolapse, a synonymous valve identity in heart flow.
Question 5 of 5
The lungs are covered by a two-layer membrane called the:
Correct Answer: A
Rationale: The pleura (A) is the two-layer membrane (visceral/parietal) covering the lungs, per the key reducing friction (15 mL fluid). The diaphragm (B) is a muscle, not a covering. The respiratory membrane (C) is the alveolar-capillary interface (0.2 μm). Intercostal muscles (D) aid breathing, not encasing lungs. Pleura's serous layers (5-10 μm thick) allow 6-8 L/min expansion, per anatomy unlike B's contraction, C's diffusion role, or D's support, A's protective sheath is the lung's hallmark.