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Questions and Answers
What is the expected partial pressure of O2 in the air saturated with water vapor at 37°C at this altitude?
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?
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?
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?
At the end of normal expiration, which statement is incorrect?
Obstructive lung disease is typically characterized by which of the following?
Obstructive lung disease is typically characterized by which of the following?
Which of the following parameters is higher in the elderly than in young adults?
Which of the following parameters is higher in the elderly than in young adults?
What is the approximate dead space of a normal adult man breathing through a 50 cm long and 6 mm in diameter tube?
What is the approximate dead space of a normal adult man breathing through a 50 cm long and 6 mm in diameter tube?
Spontaneous respiration ceases after which condition?
Spontaneous respiration ceases after which condition?
Which of the following are expected to decrease airway resistance?
Which of the following are expected to decrease airway resistance?
The physiological dead space:
The physiological dead space:
A high alveolo-arterial PO2 difference most likely results from:
A high alveolo-arterial PO2 difference most likely results from:
At 33 feet under water the ambient pressure is:
At 33 feet under water the ambient pressure is:
Which of the following combinations are typical findings in compensated respiratory alkalosis:
Which of the following combinations are typical findings in compensated respiratory alkalosis:
The partial pressure of oxygen in the alveoli is expected to be least affected by:
The partial pressure of oxygen in the alveoli is expected to be least affected by:
A veno-arterial shunt is likely to:
A veno-arterial shunt is likely to:
The arterio-venous difference of O2 is highest across:
The arterio-venous difference of O2 is highest across:
In a patient, hypoventilation is most likely if:
In a patient, hypoventilation is most likely if:
A decrease in the recoil force of the lung is likely to:
A decrease in the recoil force of the lung is likely to:
Central chemoreceptors differ from chemoreceptors in that they:
Central chemoreceptors differ from chemoreceptors in that they:
Surfactant:
Surfactant:
One month of an exposure to an inspired CO2 of 5% would result in:
One month of an exposure to an inspired CO2 of 5% would result in:
In a normal adult man, breathing 100% oxygen:
In a normal adult man, breathing 100% oxygen:
At the end of maximum inspiration:
At the end of maximum inspiration:
On ascent to a high altitude:
On ascent to a high altitude:
Compliance of the lung:
Compliance of the lung:
Dennervation of carotid and aortic bodies leads to all the following except:
Dennervation of carotid and aortic bodies leads to all the following except:
Exchange of which of the following gases across the respiratory membrane is normally diffusion limited:
Exchange of which of the following gases across the respiratory membrane is normally diffusion limited:
Minute ventilation is:
Minute ventilation is:
The ventilatory response to hypoxia:
The ventilatory response to hypoxia:
With respect to oxygen and carbon dioxide transport in the blood:
With respect to oxygen and carbon dioxide transport in the blood:
PCO2 in arterial blood:
PCO2 in arterial blood:
The functional residual capacity:
The functional residual capacity:
At the end of inspiration at sea level the PO2 in the anatomic dead space is approximately:
At the end of inspiration at sea level the PO2 in the anatomic dead space is approximately:
Which is true concerning control of ventilation:
Which is true concerning control of ventilation:
Which of the following is likely to decrease airway resistance?
Which of the following is likely to decrease airway resistance?
Compared to normal arterial blood, normal mixed venous blood has:
Compared to normal arterial blood, normal mixed venous blood has:
Deficiency of surfactant is likely to result in:
Deficiency of surfactant is likely to result in:
For a normal Hb-O2 dissociation curve, the most correct relationship is:
For a normal Hb-O2 dissociation curve, the most correct relationship is:
In a normal subject, blood at the end of the pulmonary capillary:
In a normal subject, blood at the end of the pulmonary capillary:
PCO2 in arterial blood:
PCO2 in arterial blood:
In which of the following conditions is the percent saturation of hemoglobin in arterial blood likely to be normal:
In which of the following conditions is the percent saturation of hemoglobin in arterial blood likely to be normal:
At which of the following points is the intrapleural pressure closest to zero:
At which of the following points is the intrapleural pressure closest to zero:
Regarding the vital capacity, all of the following are correct except:
Regarding the vital capacity, all of the following are correct except:
Immediate acclimatization to high altitude is by:
Immediate acclimatization to high altitude is by:
At the end of maximal expiration the volume of air in the lungs is:
At the end of maximal expiration the volume of air in the lungs is:
At the end of expiration at sea level the PO2 in the anatomic dead space is approximately:
At the end of expiration at sea level the PO2 in the anatomic dead space is approximately:
Which is true regarding lung and chest wall mechanics:
Which is true regarding lung and chest wall mechanics:
Which is true concerning the diffusing capacity of the lungs:
Which is true concerning the diffusing capacity of the lungs:
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:
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:
While repaying the O2 debt:
While repaying the O2 debt:
An average adult male has a vital capacity of:
An average adult male has a vital capacity of:
The residual volume can be calculated by subtracting the expiratory reserve volume from:
The residual volume can be calculated by subtracting the expiratory reserve volume from:
The volume of air that describes the lung's ability to eliminate carbon dioxide is:
The volume of air that describes the lung's ability to eliminate carbon dioxide is:
A decrease in the recoil force of the lung is expected to:
A decrease in the recoil force of the lung is expected to:
Deficiency of surfactant may lead to:
Deficiency of surfactant may lead to:
Continuous measurement of the concentration of nitrogen in the expired air can be used to measure:
Continuous measurement of the concentration of nitrogen in the expired air can be used to measure:
Oxygen consumption of an average adult man per minute is about:
Oxygen consumption of an average adult man per minute is about:
Which of the following is expected to increase functional residual capacity:
Which of the following is expected to increase functional residual capacity:
The most likely cause of hypoxic hypoxia together with hypercapnia is:
The most likely cause of hypoxic hypoxia together with hypercapnia is:
Which of the following is correct regarding blood in the pulmonary trunk:
Which of the following is correct regarding blood in the pulmonary trunk:
Ventilation is most sensitive to changes in:
Ventilation is most sensitive to changes in:
Inspiration is initiated by discharge from:
Inspiration is initiated by discharge from:
Voluntary hyperventilation by a normal person is expected to lead to all the following except:
Voluntary hyperventilation by a normal person is expected to lead to all the following except:
The normal diffusing capacity of the respiratory membrane of an average adult male for oxygen is about:
The normal diffusing capacity of the respiratory membrane of an average adult male for oxygen is about:
Cyanosis is unlikely to occur in:
Cyanosis is unlikely to occur in:
Which is true concerning the diffusing capacity of the lungs:
Which is true concerning the diffusing capacity of the lungs:
Which type of hypoxia in which there is a greater than normal atrial-mixed venous partial pressure difference and relatively normal arterial oxygen concentration:
Which type of hypoxia in which there is a greater than normal atrial-mixed venous partial pressure difference and relatively normal arterial oxygen concentration:
Administration of a gas mixture with higher than normal oxygen concentration at atmospheric pressure would elevate hypoxia due to:
Administration of a gas mixture with higher than normal oxygen concentration at atmospheric pressure would elevate hypoxia due to:
The PCO2 is an alveolus which is ventilated but not perfused is about:
The PCO2 is an alveolus which is ventilated but not perfused is about:
Which is true concerning surface tension in lungs:
Which is true concerning surface tension in lungs:
Which is true concerning oxygen transport in the blood:
Which is true concerning oxygen transport in the blood:
The physiological shunt:
The physiological shunt:
At the summit of a mountain the barometric pressure was found to be:
At the summit of a mountain the barometric pressure was found to be:
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!
