Respiratory System Quiz

Questions and Answers

What is the expected partial pressure of O2 in the air saturated with water vapor at 37°C at this altitude?

62 mmHg

60 mmHg

55 mmHg

45 mmHg

65 mmHg (correct)

Which of the following parameters is lower in the elderly than in young adults?

Vital capacity (correct)

Physiological dead space

Functional residual capacity (correct)

Residual volume

Lung compliance (correct)

Which statement about surfactant is true?

Production is inhibited by glucocorticoids

Deficiency decreases work of breathing

Deficiency decreases lung compliance (correct)

Is produced by type I pneumocytes

Production starts only after birth in full term babies

At the end of normal expiration, which statement is incorrect?

The average intrapleural pressure is zero Signup and view all the answers

Obstructive lung disease is typically characterized by which of the following?

Reduced FEV1 Signup and view all the answers

Which of the following parameters is higher in the elderly than in young adults?

Anatomical dead space Signup and view all the answers

What is the approximate dead space of a normal adult man breathing through a 50 cm long and 6 mm in diameter tube?

200 ml Signup and view all the answers

Spontaneous respiration ceases after which condition?

Transection of the brain stem between the pons and medulla combined with bilateral vagotomy Signup and view all the answers

Which of the following are expected to decrease airway resistance?

Atropine Signup and view all the answers

The physiological dead space:

Is higher in elderly than young adults Signup and view all the answers

A high alveolo-arterial PO2 difference most likely results from:

Pulmonary edema Signup and view all the answers

At 33 feet under water the ambient pressure is:

Two atmospheres Signup and view all the answers

Which of the following combinations are typical findings in compensated respiratory alkalosis:

Low PaCO2, low bicarbonate level and high pH Signup and view all the answers

The partial pressure of oxygen in the alveoli is expected to be least affected by:

Hemoglobin concentration Signup and view all the answers

A veno-arterial shunt is likely to:

Decrease PaO2 Signup and view all the answers

The arterio-venous difference of O2 is highest across:

Cardiac muscle Signup and view all the answers

In a patient, hypoventilation is most likely if:

PaCO2 is high Signup and view all the answers

A decrease in the recoil force of the lung is likely to:

Increase functional residual capacity Signup and view all the answers

Central chemoreceptors differ from chemoreceptors in that they:

Do not respond to changes in PO2 Signup and view all the answers

Surfactant:

All of the above Signup and view all the answers

One month of an exposure to an inspired CO2 of 5% would result in:

Reduced ventilatory sensitivity to hypoxia Signup and view all the answers

In a normal adult man, breathing 100% oxygen:

Is likely to reduce alveolar PCO2 Signup and view all the answers

At the end of maximum inspiration:

Recoil force of the chest is greater than the recoil force of the lung Signup and view all the answers

On ascent to a high altitude:

The number of oxygen molecules per liter of air decreases Signup and view all the answers

Compliance of the lung:

Is decreased in emphysematous changes Signup and view all the answers

Dennervation of carotid and aortic bodies leads to all the following except:

Absence response of ventilation to exercise Signup and view all the answers

Exchange of which of the following gases across the respiratory membrane is normally diffusion limited:

Carbon monoxide Signup and view all the answers

Minute ventilation is:

The volume of air moved in or out of the alveoli per minute Signup and view all the answers

The ventilatory response to hypoxia:

Is largely mediated by the aortic bodies in humans Signup and view all the answers

With respect to oxygen and carbon dioxide transport in the blood:

Per unit volume of arterial blood, there is more O2 than CO2 Signup and view all the answers

PCO2 in arterial blood:

Is the major controller of ventilation Signup and view all the answers

The functional residual capacity:

Is about 3 liters in an average adult male Signup and view all the answers

At the end of inspiration at sea level the PO2 in the anatomic dead space is approximately:

150 mmHg Signup and view all the answers

Which is true concerning control of ventilation:

The response of ventilation to a sustained rise in PCO2 increases with time Signup and view all the answers

Which of the following is likely to decrease airway resistance?

Breathing at higher lung volumes Signup and view all the answers

Compared to normal arterial blood, normal mixed venous blood has:

Lower PO2, higher PCO2 and lower pH Signup and view all the answers

Deficiency of surfactant is likely to result in:

Decreased compliance Signup and view all the answers

For a normal Hb-O2 dissociation curve, the most correct relationship is:

PO2 is 95 mmHg, percent saturation 97 Signup and view all the answers

In a normal subject, blood at the end of the pulmonary capillary:

Has a PO2 similar to that in the left atrium Signup and view all the answers

PCO2 in arterial blood:

Is lower than normal in compensated metabolic acidosis Signup and view all the answers

In which of the following conditions is the percent saturation of hemoglobin in arterial blood likely to be normal:

Anemia Signup and view all the answers

At which of the following points is the intrapleural pressure closest to zero:

End of maximum inspiration Signup and view all the answers

Regarding the vital capacity, all of the following are correct except:

It is normal in pure restrictive lung disease Signup and view all the answers

Immediate acclimatization to high altitude is by:

Hyperventilation Signup and view all the answers

At the end of maximal expiration the volume of air in the lungs is:

TLC - VC Signup and view all the answers

At the end of expiration at sea level the PO2 in the anatomic dead space is approximately:

40 mmHg Signup and view all the answers

Which is true regarding lung and chest wall mechanics:

At the end of normal expiration the recoil tendency of the chest is slightly greater than that of the lung Signup and view all the answers

Which is true concerning the diffusing capacity of the lungs:

It increases as the alveolar capillary surface area rises Signup and view all the answers

A person whose anatomic dead space is 100 mL breathes 12 times per minute with a tidal volume of 400 mL. His pulmonary ventilation is:

2.4 liters Signup and view all the answers

While repaying the O2 debt:

Muscle blood flow is increasing Signup and view all the answers

An average adult male has a vital capacity of:

5 liters Signup and view all the answers

The residual volume can be calculated by subtracting the expiratory reserve volume from:

Total lung capacity Signup and view all the answers

The volume of air that describes the lung's ability to eliminate carbon dioxide is:

Alveolar ventilation Signup and view all the answers

A decrease in the recoil force of the lung is expected to:

Decrease total lung capacity Signup and view all the answers

Deficiency of surfactant may lead to:

Increased work of breathing Signup and view all the answers

Continuous measurement of the concentration of nitrogen in the expired air can be used to measure:

Physiological dead space Signup and view all the answers

Oxygen consumption of an average adult man per minute is about:

250 ml Signup and view all the answers

Which of the following is expected to increase functional residual capacity:

Degeneration of lung elastic tissue Signup and view all the answers

The most likely cause of hypoxic hypoxia together with hypercapnia is:

Hypoventilation Signup and view all the answers

Which of the following is correct regarding blood in the pulmonary trunk:

50% saturation of hemoglobin Signup and view all the answers

Ventilation is most sensitive to changes in:

PCO2 Signup and view all the answers

Inspiration is initiated by discharge from:

The preBötzinger complex Signup and view all the answers

Voluntary hyperventilation by a normal person is expected to lead to all the following except:

Low blood bicarbonate concentration in arterial blood Signup and view all the answers

The normal diffusing capacity of the respiratory membrane of an average adult male for oxygen is about:

50 ml Signup and view all the answers

Cyanosis is unlikely to occur in:

Severe anemia Signup and view all the answers

Which is true concerning the diffusing capacity of the lungs:

Rises as the partial pressure gradient rises Signup and view all the answers

Which type of hypoxia in which there is a greater than normal atrial-mixed venous partial pressure difference and relatively normal arterial oxygen concentration:

Stagnant hypoxia Signup and view all the answers

Administration of a gas mixture with higher than normal oxygen concentration at atmospheric pressure would elevate hypoxia due to:

Cyanide poisoning Signup and view all the answers

The PCO2 is an alveolus which is ventilated but not perfused is about:

46 mmHg Signup and view all the answers

Which is true concerning surface tension in lungs:

In the absence of surfactant, alveoli with small radii collapse into alveoli with big radii Signup and view all the answers

Which is true concerning oxygen transport in the blood:

The P50 is the percent saturation of hemoglobin with oxygen when PO2 is 50 mmHg Signup and view all the answers

The physiological shunt:

Is about 5% of the cardiac output Signup and view all the answers

At the summit of a mountain the barometric pressure was found to be:

300 mmHg Signup and view all the answers

Study Notes

Dead Space and Shunts

Physiological dead space can be greater than anatomically defined in various conditions.
High A-a gradient indicates issues like shunting, pulmonary edema, or hypoventilation.
Veno-arterial shunts decrease PaO2 and can impact cardiovascular perfusion.

Pressure and Volume Relationships

Ambient pressure at 33 feet underwater is approximately two atmospheres.
Compliance of the lung varies based on age and conditions, generally lower in elderly and higher in infants.

Gas Exchange and Transport

Alveolar PO2 is affected by various factors, but least affected by hemoglobin concentration.
Oxygen and carbon dioxide transport in the blood differ in capacity and saturation at various pressures.

Regulation of Ventilation

Central chemoreceptors primarily respond to CO2 levels and indirectly to pH, not PO2.
Immediate acclimatization to altitude occurs through hyperventilation and increased cardiac output.

Respiratory Mechanics

End of maximum inspiration results in a balance of chest and lung recoil forces and variable surface tension.
Surface tension is crucial for lung compliance; deficiency leads to increased work of breathing, indicating its importance.

Hypoxia and Ventilatory Response

Hypoxic hypoxia may present with high atrial-mixed venous partial pressure differences.
Ventilation is most sensitive to changes in PCO2, influencing respiratory drive significantly.

Lung Functions and Clinical Implications

Vital capacity varies by sex, age, and lung condition, with diminished values in obstructive diseases.
Presence of surfactant is vital for maintaining alveolar stability and lower surface tension during lung expansion.

Physiological Responses and Adaptations

On ascent to high altitude, the concentration and number of oxygen molecules per liter decrease, impacting overall oxygen delivery.
Involuntary hyperventilation alters pH and bicarbonate levels, leading to potential alkalosis.

Pathological Considerations

Conditions like pulmonary edema, anemia, and various types of hypoxia directly affect oxygen transport and exchange efficiency.
Obstructive lung diseases are predominantly characterized by reduced FEV1 and not necessarily lower vital capacity.

General Knowledge

The average oxygen consumption for adults is around 250 ml per minute.
Changes in intrapleural pressure throughout the respiratory cycle inform mechanics of breathing and lung dynamics.

Important Values and Thresholds

Physiological shunt accounts for about 5% of cardiac output; affected by various respiratory conditions.
End-tidal CO2 and arterial PCO2 are critical in assessing ventilatory status and lung function.

Aging Effects

Functional residual capacity tends to increase with age, while vital capacity declines, indicating diminishing lung function.

Surfactant Production

Surfactant is produced by type II pneumocytes and decreases surface tension; pivotal in maintaining alveolar structure and function.

These notes encapsulate key aspects of the respiratory system, emphasizing both normal physiology and pathological states relevant to study and clinical application.

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Description

Test your knowledge of the respiratory system with this quiz that covers physiological concepts such as dead space and gas exchange. Answer questions related to how the body functions during exercise and the differences between age groups. Challenge yourself to enhance your understanding of respiratory mechanics!