Which of the following viral diseases has been eliminated from the general population worldwide?

Correct Answer: A

Rationale: Smallpox, caused by variola virus, is the only viral disease eradicated globally, declared so by WHO in 1980 after a vaccination campaign eliminated natural cases. Measles and German measles (rubella) persist measles sees outbreaks where vaccination lags, and rubella, though controlled, isn't eradicated. Influenza evolves yearly, evading elimination due to antigenic drift. Smallpox's success stemmed from its stable virus, effective vaccine, and no animal reservoir, unlike influenza's mutations or measles' human spread. This milestone showcases public health triumph, contrasting with ongoing battles against other respiratory viruses, underlining eradication's rarity and the need for sustained vaccination efforts.

Correct Answer: D

Rationale: A nonrebreather mask (D) delivers 100% oxygen (FiOâ‚‚ 0.9-1.0) for severe pneumonia hypoxemia (PaOâ‚‚ <60 mmHg), per nursing texts. Simple mask (A) maxes at 60%. Venturi (B) adjusts FiOâ‚‚ (24-50%), not 100%. Nasal cannula (C) reaches 40%. The document's answer (D) fits nonrebreather's reservoir ensures high FiOâ‚‚, critical for ARDS-like pneumonia, distinguishing it from A's lower capacity or C's inadequacy.

Correct Answer: C

Rationale: Carbon dioxide (CO2) is released during respiration, a byproduct of cellular metabolism where glucose and oxygen produce energy, water, and CO2 in mitochondria. This CO2 diffuses from tissues into the blood, is transported to the lungs, and exhaled via alveoli. Oxygen is consumed, not released it enters the blood. Hydrogen isn't a respiratory gas; it's part of water or metabolic intermediates. 'None' is incorrect CO2 expulsion is respiration's hallmark. This process balances blood pH and oxygen levels, critical for homeostasis, distinguishing respiration from photosynthesis, where CO2 is absorbed, a fundamental principle in physiology and gas exchange studies.

Correct Answer: D

Rationale: Normal breathing is controlled by the ventral and dorsal respiratory groups in the medulla and pons. The dorsal group initiates inspiration, stimulating the diaphragm via the phrenic nerve, while the ventral group adjusts forceful breathing, and the pons refines rhythm together maintaining automatic respiration based on CO2 levels. Lungs execute breathing but don't control it they respond to neural signals. This brain stem coordination ensures steady, involuntary breathing, adapting to metabolic needs, a critical autonomic process distinct from voluntary control, foundational in respiratory physiology and clinical monitoring of breathing disorders.

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.