LPN exams respiratory practice questions set 8

Correct answer:

Atmospheric air contains approximately 21% oxygen (O2) and 0.04% carbon dioxide (CO2), meaning O2's percentage is much higher than CO2's, reflecting their natural abundances. Solubility in blood, governed by Henry's law, depends on the solubility coefficient of each gas. O2 has a solubility coefficient of about 0.024 ml O2/mmHg/L blood, while CO2's is much higher at 0.51 ml CO2/mmHg/L blood over 20 times greater. This means CO2 is far more soluble in solution than O2, despite its lower atmospheric presence. In blood, O2 relies heavily on hemoglobin binding (98% of transport), with only ~1-2% dissolved, whereas CO2 is transported dissolved (~7%), as bicarbonate (~70%), and bound to hemoglobin (~23%), leveraging its high solubility. Thus, O2's higher atmospheric percentage contrasts with its lower solubility compared to CO2, driving distinct transport mechanisms critical for respiration and acid-base balance.

Correct answer:

Atmospheric air contains approximately 21% oxygen (O2) and 0.04% carbon dioxide (CO2), meaning O2's percentage is much higher than CO2's, reflecting their natural abundances. Solubility in blood, governed by Henry's law, depends on the solubility coefficient of each gas. O2 has a solubility coefficient of about 0.024 ml O2/mmHg/L blood, while CO2's is much higher at 0.51 ml CO2/mmHg/L blood over 20 times greater. This means CO2 is far more soluble in solution than O2, despite its lower atmospheric presence. In blood, O2 relies heavily on hemoglobin binding (98% of transport), with only ~1-2% dissolved, whereas CO2 is transported dissolved (~7%), as bicarbonate (~70%), and bound to hemoglobin (~23%), leveraging its high solubility. Thus, O2's higher atmospheric percentage contrasts with its lower solubility compared to CO2, driving distinct transport mechanisms critical for respiration and acid-base balance.

Correct answer:

Functional residual capacity (FRC) is the lung volume after a normal expiration (~2.5-3 L), the resting state where lung inward recoil balances chest wall outward recoil. It's the lung's resting volume, but also reflects the thorax's state, though these aren't mutually exclusive options. The key true statement is that at FRC, intra-alveolar pressure equals atmospheric pressure (~760 mmHg), as no airflow occurs (P = 0 gradient), and muscles are relaxed. Intrapleural pressure (IPP) at FRC is negative (~-4 mmHg, 756 mmHg), not more than atmospheric (760 mmHg), due to recoil forces keeping lungs expanded rising above atmospheric only in pathology (e.g., pneumothorax). Lung compliance varies with volume, not lowest at FRC, which is a mid-range point. The equality of alveolar and atmospheric pressure at FRC is a fundamental respiratory principle, ensuring stability at rest, making it the standout true statement.

Correct answer:

At the end of quiet expiration, respiratory muscles (diaphragm, intercostals) relax, and the lungs reach functional residual capacity (FRC), typically 2.5-3 liters. FRC is the resting volume where lung inward recoil balances chest wall outward recoil, maintaining equilibrium without active effort. Residual volume (RV, ~1-1.5 L) is the air left after maximal expiration, not quiet breathing. Expiratory reserve volume (ERV, ~1-1.5 L) is the extra air forcibly exhaled beyond quiet expiration, not present at rest. Inspiratory reserve volume (IRV, ~2-3 L) is additional air inhaled beyond a normal breath, irrelevant post-expiration. Total lung capacity (TLC, ~6 L) includes all volumes, not the resting state. FRC's role as the baseline volume after passive expiration reflects the natural relaxation point, critical for continuous gas exchange, distinguishing it from volumes tied to forced maneuvers or inspiration.

Correct answer:

At the end of quiet expiration, respiratory muscles (diaphragm, intercostals) relax, and the lungs reach functional residual capacity (FRC), typically 2.5-3 liters. FRC is the resting volume where lung inward recoil balances chest wall outward recoil, maintaining equilibrium without active effort. Residual volume (RV, ~1-1.5 L) is the air left after maximal expiration, not quiet breathing. Expiratory reserve volume (ERV, ~1-1.5 L) is the extra air forcibly exhaled beyond quiet expiration, not present at rest. Inspiratory reserve volume (IRV, ~2-3 L) is additional air inhaled beyond a normal breath, irrelevant post-expiration. Total lung capacity (TLC, ~6 L) includes all volumes, not the resting state. FRC's role as the baseline volume after passive expiration reflects the natural relaxation point, critical for continuous gas exchange, distinguishing it from volumes tied to forced maneuvers or inspiration.

Correct answer:

The annual influenza vaccine is the most effective health promotion activity for preventing influenza and its complication, pneumonia, especially in senior citizens who are at higher risk due to age-related immune decline. The vaccine primes the immune system to recognize and fight specific flu strains, reducing infection risk by up to 60% when well-matched, and lowering severity if infected. Hand washing reduces transmission but doesn't provide direct immunity. Avoiding crowds limits exposure but isn't as proactive or reliable as vaccination. Exercise boosts general health but lacks the specific protective effect of the vaccine against flu viruses. For seniors, who face increased morbidity from flu and pneumonia, the nurse's focus on vaccination aligns with public health priorities, offering a targeted, evidence-based strategy to prevent these respiratory illnesses and their potentially fatal outcomes.

Correct answer:

The annual influenza vaccine is the most effective health promotion activity for preventing influenza and its complication, pneumonia, especially in senior citizens who are at higher risk due to age-related immune decline. The vaccine primes the immune system to recognize and fight specific flu strains, reducing infection risk by up to 60% when well-matched, and lowering severity if infected. Hand washing reduces transmission but doesn't provide direct immunity. Avoiding crowds limits exposure but isn't as proactive or reliable as vaccination. Exercise boosts general health but lacks the specific protective effect of the vaccine against flu viruses. For seniors, who face increased morbidity from flu and pneumonia, the nurse's focus on vaccination aligns with public health priorities, offering a targeted, evidence-based strategy to prevent these respiratory illnesses and their potentially fatal outcomes.

Correct answer:

Respiratory minute ventilation (VE) is tidal volume (VT) × respiratory rate (RR), fixed here at 6 L/min (6000 ml/min). Alveolar ventilation (VA) is the air reaching alveoli for gas exchange: VA = (VT - VD) × RR, where anatomic dead space (VD) is 150 ml. For 200 ml at 30/min: VE = 200 × 30 = 6000 ml/min, VA = (200 - 150) × 30 = 50 × 30 = 1500 ml/min. For 300 ml at 20/min: VE = 300 × 20 = 6000 ml/min, VA = (300 - 150) × 20 = 150 × 20 = 3000 ml/min. For 400 ml at 15/min: VE = 400 × 15 = 6000 ml/min, VA = (400 - 150) × 15 = 250 × 15 = 3750 ml/min. For 600 ml at 10/min: VE = 600 × 10 = 6000 ml/min, VA = (600 - 150) × 10 = 450 × 10 = 4500 ml/min. The 600 ml at 10/min yields the highest VA (4.5 L/min), as larger VT maximizes air past the fixed VD, despite lower RR. Higher rates with smaller VT waste more ventilation in dead space, reducing VA efficiency, making the deeper, slower pattern optimal.

Correct answer:

The correct answer is D. Inhibition of medulla oblongata chemoreceptors and respiratory muscles would decrease respiratory rate, leading to decreased elimination of CO2 at alveoli. This would cause an increase in arterial PCO2 due to less CO2 being removed from the body. Therefore, choice D is correct. Choices A, B, and C are incorrect because they do not align with the physiological effects of inhibiting the medulla oblongata chemoreceptors and respiratory muscles. Option A suggests an increase in respiratory rate and elimination of CO2, which goes against the expected decrease in these parameters. Option B proposes an increase in respiratory rate but a decrease in CO2 elimination and arterial PCO2, which is inconsistent with the expected outcomes. Option C suggests an increase in respiratory rate and CO2 elimination but a decrease in arterial PCO2, which does not follow the logic of the question.

Correct answer:

Influenza in a 67-year-old increases the risk of sinusitis and otitis media, secondary infections stemming from viral irritation of the upper respiratory tract. Sinusitis arises when flu causes sinus inflammation, trapping bacteria, while otitis media follows eustachian tube dysfunction from nasal congestion, common in older adults with weakened immunity. Arthritis and Cushing's syndrome are unrelated flu doesn't affect joints or cortisol long-term. Aortic valve prolapse involves heart structure, not infection risk. Gastritis and goiter concern the stomach and thyroid, not respiratory complications. The nurse recognizes sinusitis and otitis media as frequent flu sequelae in seniors, whose immune response and mucosal clearance decline with age, necessitating monitoring for symptoms like ear pain or sinus pressure to prevent untreated bacterial superinfections that could worsen the client's condition.