Respiratory System

Respiratory System Indian Medical PG Question 1: A 68-year-old man with both severe COPD (emphysema) and newly diagnosed idiopathic pulmonary fibrosis presents with worsening dyspnea. His pressure-volume curve shows a complex pattern with features of both diseases. Static compliance measured at mid-lung volumes is 120 mL/cm H2O. His pulmonologist must decide on optimal management. Synthesizing the pathophysiology of both conditions, what represents the most significant clinical challenge in managing his combined disease?

• A. The opposing effects on compliance create a pseudonormal total respiratory compliance masking disease severity (Correct Answer)
• B. The increased compliance from emphysema completely negates decreased compliance from fibrosis
• C. Oxygen therapy beneficial for COPD will accelerate fibrotic changes
• D. Emphysema treatment with bronchodilators will worsen fibrosis progression
• E. Pulmonary rehabilitation cannot address the opposing mechanical derangements

Respiratory System Explanation: ***The opposing effects on compliance create a pseudonormal total respiratory compliance masking disease severity*** - In **Combined Pulmonary Fibrosis and Emphysema (CPFE)**, the increased compliance of emphysema (due to **alveolar destruction**) and decreased compliance of fibrosis (due to **stiffening**) counteract each other. - This leads to a **pseudonormalization of lung volumes** and compliance measures, which can dangerously mask the severe impairment of **gas exchange** and the extent of parenchymal damage. *The increased compliance from emphysema completely negates decreased compliance from fibrosis* - While the mechanics oppose each other, they rarely result in a complete negation; rather, they produce a **hybrid physiological profile** where values fall in a deceptively "normal" range. - Even if compliance appears normal, the **DLCO** (diffusing capacity) is significantly and synergistically reduced, indicating severe disease presence. *Oxygen therapy beneficial for COPD will accelerate fibrotic changes* - Standard **supplemental oxygen** used in COPD management does not physiologically accelerate the process of **idiopathic pulmonary fibrosis**. - Oxygen therapy is actually crucial in CPFE patients to manage **hypoxemia** and secondary **pulmonary hypertension**, which is highly prevalent in this cohort. *Emphysema treatment with bronchodilators will worsen fibrosis progression* - Bronchodilators act on **airway smooth muscle** and do not influence the **fibroblastic proliferation** or collagen deposition seen in fibrosis. - There is no clinical or physiological evidence suggesting that inhaler therapy for the obstructive component of CPFE negatively impacts the **restrictive pathology**. *Pulmonary rehabilitation cannot address the opposing mechanical derangements* - While **pulmonary rehabilitation** cannot reverse the mechanical changes in compliance, it is highly effective at improving **functional capacity** and quality of life. - The challenge is not the effectiveness of rehabilitation, but the **diagnostic difficulty** and the high risk of developing severe **pulmonary hypertension**.

Respiratory System Indian Medical PG Question 2: A 42-year-old woman with systemic sclerosis develops both pulmonary fibrosis and chest wall restriction from skin thickening. Her measured total respiratory system compliance is 30 mL/cm H2O. Testing with complete paralysis and positive pressure ventilation shows isolated lung compliance of 50 mL/cm H2O. She is being considered for immunosuppressive therapy versus supportive care. Evaluate which intervention would provide the greatest improvement in her respiratory mechanics.

• A. Aggressive immunosuppression targeting both lung and skin disease
• B. Combined therapy targeting lung disease with chest wall mobilization (Correct Answer)
• C. Chest wall-directed physical therapy, as it is the primary limiting factor
• D. Lung-directed therapy only, as it contributes more to total compliance reduction
• E. Supportive care only, as both components contribute equally and irreversibly

Respiratory System Explanation: ***Combined therapy targeting lung disease with chest wall mobilization*** - Using the respiratory mechanics formula **1/Ctotal = 1/Clung + 1/Cchest wall**, the chest wall compliance is calculated as **75 mL/cm H2O** (1/30 - 1/50 = 1/75), indicating both the lungs and chest wall are severely impaired. - Because both components contribute significantly to the **total respiratory system stiffness**, a dual approach addressing **interstitial lung disease** and **extrapulmonary restriction** provides the maximal physiological benefit. *Aggressive immunosuppression targeting both lung and skin disease* - While targeting the underlying pathology of **systemic sclerosis**, immunosuppression alone may not provide immediate mechanical relief for **chest wall restriction**. - This option ignores the specific mechanical contribution of **chest wall stiffness** (75 mL/cm H2O) which often requires physical mobilization or localized therapy beyond systemic drugs. *Chest wall-directed physical therapy, as it is the primary limiting factor* - Measured **lung compliance (Clung)** is 50 mL/cm H2O, which is significantly lower than the calculated **chest wall compliance (Cw)** of 75 mL/cm H2O. - Therefore, the **pulmonary parenchyma** is actually the more restricted component, making therapy focused solely on the chest wall insufficient for the patient's condition. *Lung-directed therapy only, as it contributes more to total compliance reduction* - Although the lung has a lower compliance (50 vs 75), the **total compliance** of the system is the reciprocal sum of both; ignore the chest wall and the patient remains significantly restricted. - In **restrictive lung disease** with multi-factorial causes, addressing only one deficit leaves the **work of breathing** excessively high due to the remaining chest wall stiffness. *Supportive care only, as both components contribute equally and irreversibly* - Both components are indeed reduced, but they are not the same (50 vs 75), and **systemic sclerosis**-associated lung disease is often manageable with **mycophenolate** or other agents. - Labeling these mechanics as entirely **irreversible** is clinically inappropriate as interventions can improve quality of life and stabilize **pulmonary function tests**.

Respiratory System Indian Medical PG Question 3: A 58-year-old man with end-stage pulmonary fibrosis is being evaluated for lung transplantation. His current static compliance is 25 mL/cm H2O (normal: 200 mL/cm H2O). He also has mild obesity (BMI 32) and ankylosing spondylitis affecting chest wall mobility. Post-transplant, assuming successful bilateral lung transplant with normal donor lungs, what would be the expected change in his total respiratory system compliance?

• A. Worse compliance initially due to transplant rejection and denervation
• B. Improved but still reduced compliance due to persistent chest wall restriction (Correct Answer)
• C. Improved lung compliance but worsened chest wall compliance from surgery
• D. No significant change because the primary problem is muscular weakness
• E. Return to completely normal respiratory compliance matching healthy individuals

Respiratory System Explanation: ***Improved but still reduced compliance due to persistent chest wall restriction*** - Total respiratory system compliance is the **sum of reciprocals** of lung compliance and chest wall compliance (1/Ct = 1/Cl + 1/Ccw). - While the transplant corrects the **pulmonary fibrosis** (restoring lung compliance), the patient's **ankylosing spondylitis** and **obesity** continue to limit chest wall expansion and total compliance. *Worse compliance initially due to transplant rejection and denervation* - Successful transplantation immediately improves the severe **restrictive physiology** caused by fibrosis, outweighing potential early inflammatory changes. - **Denervation** affects the cough reflex but does not fundamentally decrease the **static elastic properties** of the new lung tissue. *Improved lung compliance but worsened chest wall compliance from surgery* - Surgical trauma may cause transient pain or guarding, but it does not represent the primary **long-term physiological limit** in this clinical scenario. - The persistent chest wall restriction is primarily due to pre-existing **ankylosing spondylitis** and **BMI**, rather than the surgical procedure itself. *No significant change because the primary problem is muscular weakness* - The primary problem in this patient is **structural and elastic**, involving fibrotic lung tissue and a rigid chest wall, not **neuromuscular junction** failure. - Replacing the fibrotic lungs with **distensible donor lungs** will result in a significant, measurable improvement in total system compliance. *Return to completely normal respiratory compliance matching healthy individuals* - Total compliance cannot return to **200 mL/cm H2O** because the **extrapulmonary restrictions** (chest wall rigidity) remain uncorrected. - The compliance of the total system is always **lower** than the compliance of its most restricted individual component.

Respiratory System Indian Medical PG Question 4: A research study compares two patients with different lung pathologies but identical functional residual capacity (FRC) of 3.0 L. Patient A has pulmonary fibrosis with FRC above the steep portion of the compliance curve. Patient B has emphysema with FRC on the flat upper portion of the curve. Both attempt to inhale the same tidal volume. Analyzing their work of breathing, which statement best characterizes the difference?

• A. Patient A does less work because fibrotic lungs have increased elastic recoil assisting inspiration
• B. Patient B does more elastic work due to hyperinflation beyond optimal compliance (Correct Answer)
• C. Patient B does less work because emphysematous lungs are more compliant
• D. Both do equal work because FRC and tidal volumes are identical
• E. Patient A does more elastic work; Patient B does more resistive work

Respiratory System Explanation: ***Patient B does more elastic work due to hyperinflation beyond optimal compliance*** - In **emphysema**, although total lung compliance is increased, breathing at high volumes (hyperinflation) places the patient on the **flat, upper portion** of the pressure-volume curve where **dynamic compliance** is very low. - This requires a significant increase in **inspiratory effort** and pressure to achieve even a small change in **tidal volume**, leading to elevated **elastic work**. *Patient A does less work because fibrotic lungs have increased elastic recoil assisting inspiration* - **Pulmonary fibrosis** actually increases **elastic recoil**, which opposes inspiration and significantly increases the **elastic work of breathing**. - Increased recoil does not assist inspiration; it requires the patient to generate more negative **intrapleural pressure** to expand the stiff lungs. *Patient B does less work because emphysematous lungs are more compliant* - While **emphysematous lungs** are globally more compliant due to alveolar wall destruction, the patient in this scenario is breathing at a **high FRC** on the flat part of the curve. - On this **plateau**, the change in volume for a given change in pressure is minimal, meaning the **effective compliance** is actually lower than on the steep portion. *Both do equal work because FRC and tidal volumes are identical* - The **work of breathing** is determined by the area under the **pressure-volume loop**, which depends on the specific compliance at the volume being inhaled. - Identical volumes do not result in equal work if the patients are operating on different segments of their respective **compliance curves**. *Patient A does more elastic work; Patient B does more resistive work* - Both patients have increased **elastic work**, but the scenario specifically highlights Patient B's position on the **inefficient flat portion** of the curve. - While **emphysema** involves increased **resistive work** (airway collapse), the question focuses on the mechanical disadvantage of **hyperinflation** on the pressure-volume relationship.

Respiratory System Indian Medical PG Question 5: A 32-year-old woman develops acute respiratory distress syndrome (ARDS) following sepsis. She is mechanically ventilated with tidal volume 450 mL and plateau pressure 35 cm H2O (PEEP 10 cm H2O). Her static compliance is calculated as 18 mL/cm H2O. The team considers changing ventilator settings. Analyzing her respiratory mechanics, what change would most effectively improve compliance while minimizing ventilator-induced lung injury?

• A. Increase tidal volume to 600 mL to recruit more alveoli
• B. Switch to pressure-control mode with same plateau pressure
• C. Increase PEEP to 15 cm H2O to prevent alveolar collapse (Correct Answer)
• D. Increase respiratory rate while maintaining current tidal volume
• E. Decrease PEEP to 5 cm H2O to reduce plateau pressure

Respiratory System Explanation: ***Increase PEEP to 15 cm H2O to prevent alveolar collapse*** - Increasing **Positive End-Expiratory Pressure (PEEP)** helps recruit collapsed alveoli in **ARDS**, effectively increasing the functional lung volume and shifting the lung to a more compliant part of the **pressure-volume curve**. - This strategy prevents **atelectrauma** (cyclic collapse and reopening) and improves **static compliance** by maintaining alveolar patency throughout the respiratory cycle. *Increase tidal volume to 600 mL to recruit more alveoli* - Increasing **tidal volume** in a patient with a high **plateau pressure** (35 cm H2O) significantly increases the risk of **volutrauma** and **barotrauma**. - Current ARDS guidelines recommend **low tidal volume ventilation** (6 mL/kg predicted body weight) to minimize **ventilator-induced lung injury (VILI)**. *Switch to pressure-control mode with same plateau pressure* - Switching to **pressure-control mode** while maintaining a high **plateau pressure** does not address the underlying issue of low **lung compliance** or alveolar recruitment. - This change primarily alters the **flow waveform** but does not inherently reduce the risk of injury if the distending pressures remain excessive. *Increase respiratory rate while maintaining current tidal volume* - Increasing the **respiratory rate** may help manage **hypercapnia** and pH, but it does not improve **static compliance** or recruit new lung units. - High rates can lead to **auto-PEEP** (intrinsic PEEP) if the expiratory time is insufficient, potentially worsening hemodynamic stability. *Decrease PEEP to 5 cm H2O to reduce plateau pressure* - While decreasing PEEP would lower the **plateau pressure**, it would likely lead to widespread **alveolar derecruitment** and worsening hypoxia. - Reducing PEEP to low levels in ARDS promotes **atelectrauma**, which is a primary driver of **lung inflammation** and ventilator-induced injury.

Respiratory System Indian Medical PG Question 6: A 55-year-old woman with idiopathic pulmonary fibrosis and a 40-year-old man with severe emphysema both have the same total lung capacity of 4.5 L on pulmonary function testing. However, their pressure-volume curves show opposite patterns. During inspiration from FRC, which patient requires greater change in pleural pressure to achieve the same tidal volume, and why?

• A. The emphysema patient, because decreased elastic recoil requires more negative pressure to inflate
• B. The fibrosis patient, because decreased compliance requires greater pressure change for the same volume (Correct Answer)
• C. The emphysema patient, because increased airway resistance requires more driving pressure
• D. The fibrosis patient, because increased surface tension prevents alveolar expansion
• E. Both require the same pressure because they have equal total lung capacity

Respiratory System Explanation: ***The fibrosis patient, because decreased compliance requires greater pressure change for the same volume*** - **Pulmonary fibrosis** involves the deposition of excess connective tissue, which increases **elastic recoil** and significantly reduces **lung compliance** (ΔV/ΔP). - Due to the **stiff lungs**, the patient must generate a much larger change in **pleural pressure** (more negative) to overcome the resistance to stretching and pull in a standard **tidal volume**. *The emphysema patient, because decreased elastic recoil requires more negative pressure to inflate* - **Emphysema** is characterized by the destruction of alveolar walls, leading to **increased lung compliance** and a "floppy" lung structure. - Patients with emphysema actually require **less negative pressure** to expand the lungs because the loss of elastin makes them very easy to distend. *The emphysema patient, because increased airway resistance requires more driving pressure* - While emphysema does involve **airway resistance** (especially during expiration due to dynamic compression), the question focuses on the **pressure-volume curve** mechanics during inspiration. - **Compliance** is the primary determinant of the pressure required to reach a specific volume in these restrictive versus obstructive models. *The fibrosis patient, because increased surface tension prevents alveolar expansion* - While **surface tension** does affect lung mechanics, the primary pathology in fibrosis is the **thickening of the interstitium** with collagen, not a primary surfactant deficiency. - Increased **elastic recoil** in fibrosis is predominantly due to the **fibrotic tissue matrix** rather than changes in alveolar fluid surface tension. *Both require the same pressure because they have equal total lung capacity* - **Total Lung Capacity (TLC)** is a static lung volume and does not reflect the **dynamic or static compliance** of the lung tissue. - Two patients can have the same **TLC** while having completely different **slopes on a P-V curve**, meaning their work of breathing and pressure requirements differ significantly.

Respiratory System Indian Medical PG Question 7: A 70-year-old man with severe kyphoscoliosis presents with chronic dyspnea. Pulmonary function testing shows reduced total lung capacity and functional residual capacity. His lung tissue biopsy is normal, but respiratory muscle strength testing shows normal values. Analysis of his pressure-volume curve shows a normal curve for lung tissue alone, but decreased total respiratory system compliance. What explains his respiratory mechanics?

• A. Primary decrease in lung compliance from parenchymal disease
• B. Primary decrease in chest wall compliance from skeletal deformity (Correct Answer)
• C. Increased lung compliance with normal chest wall compliance
• D. Respiratory muscle weakness reducing lung volumes
• E. Combined decrease in lung and chest wall compliance

Respiratory System Explanation: ***Primary decrease in chest wall compliance from skeletal deformity*** - Severe **kyphoscoliosis** creates a mechanical restriction by distorting the thoracic cage, which directly **decreases chest wall compliance** and increases the work of breathing. - The total respiratory system compliance is reduced even though the **lung tissue pressure-volume curve** is normal, confirming the pathology is extrinsic to the lungs. *Primary decrease in lung compliance from parenchymal disease* - This would typically be seen in **interstitial lung disease** or fibrosis, but this patient's **lung tissue biopsy** and pressure-volume curve were normal. - Parenchymal disease would show a shift in the lung tissue curve itself, not just the **total respiratory system** curve. *Increased lung compliance with normal chest wall compliance* - Increased compliance is characteristic of **emphysema**, where the loss of elastic recoil makes the lungs easier to distend. - This patient shows a **restrictive pattern** (low TLC and FRC) and a decrease in total compliance, which is the opposite of this scenario. *Respiratory muscle weakness reducing lung volumes* - While weakness can reduce volumes, the patient's **respiratory muscle strength testing** showed normal values, ruling out neuromuscular causes. - Muscle weakness does not inherently change the **compliance (elasticity)** of the chest wall or lung tissue fibers. *Combined decrease in lung and chest wall compliance* - While chronic chest wall restriction can sometimes lead to secondary **micro-atelectasis**, the question explicitly states the **lung tissue pressure-volume curve** is normal. - A combined decrease would require evidence of intrinsic lung changes, which is contradicted by the **normal biopsy** finding.

Respiratory System Indian Medical PG Question 8: A premature infant born at 28 weeks gestation develops respiratory distress syndrome. Arterial blood gas shows pH 7.25, PaCO2 55 mmHg, PaO2 50 mmHg on 60% FiO2. Chest X-ray reveals ground-glass opacities. Surfactant therapy is administered. Which mechanism best explains the improvement in lung mechanics following treatment?

• A. Bronchodilation decreasing airway resistance
• B. Decreased alveolar surface tension increasing compliance (Correct Answer)
• C. Increased elastic recoil decreasing compliance
• D. Increased pulmonary blood flow improving V/Q matching
• E. Strengthened alveolar walls increasing elastic fibers

Respiratory System Explanation: ***Decreased alveolar surface tension increasing compliance*** - Surfactant acts as a detergent to **reduce surface tension** at the air-liquid interface of the alveoli, preventing collapse during expiration as described by **Laplace's Law**. - By lowering surface tension, it increases **lung compliance**, making it easier for the lungs to expand and significantly decreasing the **work of breathing**. *Bronchodilation decreasing airway resistance* - Surfactant primarily affects the **alveolar interface** and lung parenchyma rather than the smooth muscles of the **conducting airways**. - Respiratory distress syndrome in neonates is a disease of **atelectasis** and restrictive physiology, not obstructive airway resistance. *Increased elastic recoil decreasing compliance* - Increased elastic recoil would actually make the lungs stiffer and **decrease compliance**, which is the exact opposite of what surfactant therapy achieves. - Surfactant functions to counteract **excessive recoil forces** caused by the high surface tension of water molecules in the alveoli. *Increased pulmonary blood flow improving V/Q matching* - While oxygenation improves, the primary mechanical effect of surfactant is on **ventilation and compliance** rather than a direct primary action on pulmonary vasculature. - Improvements in **V/Q matching** are secondary to the stabilization of alveoli and the resolution of **intrapulmonary shunting**. *Strengthened alveolar walls increasing elastic fibers* - Surfactant is a **lipoprotein complex** secreted by **Type II pneumocytes**; it does not physically alter the structural fiber composition of the alveolar basement membrane. - Chronic changes in **elastic fibers** are related to lung development and remodeling, whereas surfactant provides an immediate **biophysical effect**.

Respiratory System Indian Medical PG Question 9: A 45-year-old woman presents with progressive dyspnea and dry cough over 6 months. Chest CT shows bilateral interstitial infiltrates. Pulmonary function tests reveal FEV1/FVC ratio of 0.85, reduced total lung capacity, and a steep pressure-volume curve shifted downward and to the right. What is the primary mechanical change in her lungs?

• A. Normal lung compliance with decreased chest wall compliance
• B. Increased lung compliance with normal chest wall compliance
• C. Decreased lung compliance with normal chest wall compliance (Correct Answer)
• D. Increased lung and chest wall compliance
• E. Decreased lung and increased chest wall compliance

Respiratory System Explanation: ***Decreased lung compliance with normal chest wall compliance*** - The pressure-volume curve shifted **downward and to the right** indicates that a higher transpulmonary pressure is required to achieve a given volume, which is the hallmark of **decreased lung compliance**. - This patient's presentation of **interstitial infiltrates**, a high **FEV1/FVC ratio (>0.70)**, and reduced **total lung capacity** is characteristic of **restrictive lung disease** (e.g., pulmonary fibrosis). *Normal lung compliance with decreased chest wall compliance* - While this pattern also causes restrictive physiology, it is seen in **extrapulmonary conditions** like obesity, kyphoscoliosis, or **neuromuscular disorders**. - The clinical presence of **bilateral interstitial infiltrates** on CT confirms the pathology is within the lung parenchyma itself, not the chest wall. *Increased lung compliance with normal chest wall compliance* - This is characteristic of **obstructive lung diseases** like **emphysema**, where the loss of elastic tissue makes the lung easier to distend. - Emphysema would produce an **upward and leftward shift** of the pressure-volume curve and a **decreased FEV1/FVC ratio**. *Increased lung and chest wall compliance* - This combination does not typically occur in standard disease states; usually, factors that increase compliance in one decrease it in the other or affect only one component. - High lung compliance is associated with **obstructive disease**, which contradicts the high FEV1/FVC and **interstitial infiltrates** seen here. *Decreased lung and increased chest wall compliance* - While lung compliance is decreased in fibrosis, there is no clinical mechanism in this patient to cause **increased chest wall compliance** (loss of chest wall rigidity). - The pathology is localized to the pulmonary interstitium, and the **steep downward shift** of the curve is driven specifically by the **increased elastic recoil** of the lungs.

Respiratory System Indian Medical PG Question 10: A 65-year-old man with COPD undergoes pulmonary function testing. His FEV1 is 65% predicted, and spirometry shows an obstructive pattern. A pressure-volume loop demonstrates reduced elastic recoil with increased total lung capacity. When comparing his lungs to a healthy individual, what physiological change best explains his altered compliance?

• A. Increased alveolar surface tension from surfactant deficiency
• B. Bronchial smooth muscle hypertrophy
• C. Destruction of elastic tissue in alveolar walls (Correct Answer)
• D. Pulmonary vascular remodeling
• E. Increased collagen deposition in interstitial spaces

Respiratory System Explanation: ***Destruction of elastic tissue in alveolar walls*** - In **emphysema** (a component of **COPD**), the loss of **elastin fiber** integrity increases **lung compliance**, making the lungs more easily distensible but less able to recoil. - This destruction leads to a higher **Total Lung Capacity (TLC)** and **air trapping**, shift the pressure-volume loop upward and to the left due to **reduced elastic recoil**. *Increased alveolar surface tension from surfactant deficiency* - **Surfactant deficiency** increases surface tension, which **decreases lung compliance**, making the lungs stiff and difficult to inflate. - This is a hallmark of **Neonatal Respiratory Distress Syndrome (NRDS)**, not the obstructive pattern seen in COPD or emphysema. *Bronchial smooth muscle hypertrophy* - **Smooth muscle hypertrophy** and hyperresponsiveness primarily **increase airway resistance**, contributing to the **obstructive pattern** found in asthma and chronic bronchitis. - While it affects **FEV1**, it does not explain the specific change in **lung compliance** or the reduction in **elastic recoil** seen on a pressure-volume loop. *Pulmonary vascular remodeling* - **Vascular remodeling** and **intimal thickening** lead to **pulmonary hypertension**, which is a common sequela of chronic COPD but does not directly modify the lung's mechanical compliance. - This change primarily affects **right heart function** and gas exchange rather than the elastic properties of the alveolar septa. *Increased collagen deposition in interstitial spaces* - **Collagen deposition** is characteristic of **Restrictive Lung Diseases** (like idiopathic pulmonary fibrosis), which **decreases lung compliance**. - This pathology results in a **reduced Total Lung Capacity**, which is the physiological opposite of the increased volume and high compliance described in this case.

Respiratory System Flashcard 1 of 10

Question: The graph given below shows _____ _____thoracic obstruction

Answer: variable

Respiratory System Flashcard 2 of 10

Question: The graph given depicts the _____ effect

Answer: Haldane

Respiratory System Flashcard 3 of 10

Question: The alveolar gas equation states that the alveolar Po2 (PAo2) equals: _____

Answer:

Respiratory System Flashcard 4 of 10

Question: According to Fick's law, the rate of diffusion of a gas (Vgas) is equal to: _____

Answer:

Respiratory System Flashcard 5 of 10

Question: What equation may be used to determine the physiologic dead space (VD)? _____

Answer:

Respiratory System Flashcard 6 of 10

Question: What type of upper airway obstruction is depicted by the following flow-volume loop? _____

Answer: Variable intrathoracic obstruction

Respiratory System Flashcard 7 of 10

Question: _____ O2 binding to hemoglobin causes decreased affinity for CO2 (Haldane effect)

Answer: Increased

Respiratory System Flashcard 8 of 10

Question: The V/Q ratio at the apex of the lung is normally _____, indicating wasted ventilation

Answer: 3

Respiratory System Flashcard 9 of 10

Question: The _____ lining the epithelium of the respiratory tract help clear mucus and debris from the lungs via the mucociliary escalator

Answer: cilia

Respiratory System Flashcard 10 of 10

Question: The respiratory quotient, if someone is on an exclusive _____ diet, is 0.81.

Answer: protein