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Questions and Answers
Which of the following is NOT a function of the respiratory system?
Which of the following is NOT a function of the respiratory system?
During pulmonary ventilation, what happens to the pressure inside the lungs when the diaphragm contracts?
During pulmonary ventilation, what happens to the pressure inside the lungs when the diaphragm contracts?
Which of the following muscles is considered an accessory muscle of inspiration?
Which of the following muscles is considered an accessory muscle of inspiration?
Which process primarily involves the exchange of gases between the alveoli and the blood?
Which process primarily involves the exchange of gases between the alveoli and the blood?
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What influences the efficiency of pulmonary ventilation?
What influences the efficiency of pulmonary ventilation?
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What is the main function of internal respiration?
What is the main function of internal respiration?
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During inhalation, what happens to the diaphragm?
During inhalation, what happens to the diaphragm?
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Which muscle primarily assists in normal quiet breathing?
Which muscle primarily assists in normal quiet breathing?
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What occurs during exhalation in terms of thoracic cavity volume?
What occurs during exhalation in terms of thoracic cavity volume?
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What is the primary role of the phrenic nerve?
What is the primary role of the phrenic nerve?
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Which statement about pulmonary ventilation is accurate?
Which statement about pulmonary ventilation is accurate?
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Which of the following muscles assists with breathing during deep or difficult breaths?
Which of the following muscles assists with breathing during deep or difficult breaths?
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What happens to the external intercostal muscles during inhalation?
What happens to the external intercostal muscles during inhalation?
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What effect does the diaphragm's descent have during normal quiet inhalation?
What effect does the diaphragm's descent have during normal quiet inhalation?
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Which of the following is primarily responsible for elevating the ribs during inhalation?
Which of the following is primarily responsible for elevating the ribs during inhalation?
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What changes occur in the intrapleural pressure just before inhalation?
What changes occur in the intrapleural pressure just before inhalation?
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How much air is typically inhaled during strenuous breathing?
How much air is typically inhaled during strenuous breathing?
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What is the primary role of accessory muscles of inspiration?
What is the primary role of accessory muscles of inspiration?
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Which muscle is responsible for enlarging the upper rib cage during forced inhalation?
Which muscle is responsible for enlarging the upper rib cage during forced inhalation?
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What happens to the volume of the pleural cavity as the diaphragm and external intercostals contract?
What happens to the volume of the pleural cavity as the diaphragm and external intercostals contract?
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What is the effect of the external intercostal muscle contraction on the chest cavity?
What is the effect of the external intercostal muscle contraction on the chest cavity?
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What does vital capacity (VC) represent in lung function?
What does vital capacity (VC) represent in lung function?
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Which of the following correctly defines inspiratory reserve volume (IRV)?
Which of the following correctly defines inspiratory reserve volume (IRV)?
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Which lung volume capacity cannot be directly measured and represents air remaining in the lungs after forced expiration?
Which lung volume capacity cannot be directly measured and represents air remaining in the lungs after forced expiration?
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What is the function of functional residual capacity (FRC) in the respiratory system?
What is the function of functional residual capacity (FRC) in the respiratory system?
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How is vital capacity (VC) calculated?
How is vital capacity (VC) calculated?
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What causes the parietal and visceral pleurae to adhere closely during thoracic expansion?
What causes the parietal and visceral pleurae to adhere closely during thoracic expansion?
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Which of the following demonstrates the active process of inhalation?
Which of the following demonstrates the active process of inhalation?
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During inhalation, the pressure inside the alveoli decreases. What is the typical alveolar pressure during this phase?
During inhalation, the pressure inside the alveoli decreases. What is the typical alveolar pressure during this phase?
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What initiates the process of exhalation?
What initiates the process of exhalation?
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Which two forces contribute to the elastic recoil of the lungs during exhalation?
Which two forces contribute to the elastic recoil of the lungs during exhalation?
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What happens to the thoracic cavity as the diaphragm relaxes during exhalation?
What happens to the thoracic cavity as the diaphragm relaxes during exhalation?
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Which of the following is a characteristic of normal quiet exhalation?
Which of the following is a characteristic of normal quiet exhalation?
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Air flows from areas of higher pressure to lower pressure. During inhalation, this is primarily due to:
Air flows from areas of higher pressure to lower pressure. During inhalation, this is primarily due to:
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What does surface tension of the alveolar fluid primarily produce during inhalation?
What does surface tension of the alveolar fluid primarily produce during inhalation?
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What is indicated by high compliance in the lungs?
What is indicated by high compliance in the lungs?
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What factor is NOT primarily related to lung compliance?
What factor is NOT primarily related to lung compliance?
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What happens to airway resistance during exhalation?
What happens to airway resistance during exhalation?
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Which factor can lead to decreased lung compliance?
Which factor can lead to decreased lung compliance?
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What is the primary effect of surface tension on lung elastic recoil?
What is the primary effect of surface tension on lung elastic recoil?
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Which condition can cause increased airway resistance?
Which condition can cause increased airway resistance?
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How is the airflow through the airways primarily determined?
How is the airflow through the airways primarily determined?
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Why do healthy lungs exhibit high compliance?
Why do healthy lungs exhibit high compliance?
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Study Notes
Introduction to Respiratory Physiology
- The respiratory system's function is to supply oxygen to the body and remove carbon dioxide.
- Other functions include regulation of blood pH, phonation and defense against microbes.
Subtopics and Learning Outcomes
- The course covers the physiology of the respiratory system.
- Students should be able to describe the functions of the respiratory system.
- Understand gas and pressure changes during pulmonary ventilation.
- Describe the mechanism of respiration.
- Name the muscles involved.
- Describe intrapleural and intraplumonic pressure.
- Summarize factors influencing pulmonary ventilation.
- Define lung volumes and capacities.
Gas Exchange
- Respiration has three stages:
- Pulmonary ventilation (breathing): Inhalation and exhalation of air.
- External respiration (pulmonary respiration): Exchange of gases between alveoli of the lungs and blood in pulmonary capillaries.
- Internal respiration (tissue respiration): Exchange of gases between blood in systemic capillaries and tissue cells.
Pressure Changes During Pulmonary Ventilation
- Air flows from high to low pressure.
- Air moves into the lungs when the pressure inside the lungs is lower than atmospheric pressure.
- Air moves out of the lungs when the pressure inside the lungs is higher than atmospheric pressure.
Mechanism of Respiration
-
Inhalation:
- Internal intercostal muscles relax.
- External intercostal muscles contract.
- Rib cage moves upward and outwards.
- Diaphragm contracts and flattens.
- Thorax cavity volume increases.
- Alveolar pressure decreases.
-
Exhalation:
- Internal intercostal muscles contract.
- External intercostal muscles relax.
- Rib cage moves downward and inwards.
- Diaphragm relaxes and arches up.
- Thorax cavity volume decreases.
- Alveolar pressure increases.
- Air flows into lungs when pressure there is less that atmospheric pressure.
- Air flows out of lungs when pressure there is higher than atmospheric pressure.
Muscles of Respiration
- Diaphragm: The primary muscle of inhalation; its contraction flattens the dome, increasing thoracic cavity volume.
- External Intercostal muscles: Elevate ribs during inhalation, increasing the thoracic cavity's anteroposterior and lateral diameters.
- Accessory muscles: Involved in forced breathing (e.g., exercise, coughing, sneezing) including scalenes, pectoralis major/minor, and sternocleidomastoid.
Intrapleural Pressure
- Pressure between the two pleural layers is subatmospheric (lower than atmospheric pressure).
- During inhalation, the intrapleural pressure decreases.
- The difference between the intra-alveolar pressure and intrapleural pressure is called transpulmonary pressure.
Alveolar (Intrapulmonic) Pressure
- Pressure inside the lungs.
- During inhalation, alveolar pressure decreases.
- Air moves into the lungs as pressure inside the lungs is lower.
- For exhalation, the pressures are reversed.
Active and Passive Processes of Breathing
- Inhalation is usually an active process, involving muscle contractions to increase lung volume.
- Exhalation is primarily a passive process, relying on elastic recoil of the lungs and chest wall, with minimal muscular effort in regular breathing.
Factors Affecting Pulmonary Ventilation
- Surface tension of Alveolar Fluid: This force tends to reduce alveolar size; surfactant reduces surface tension.
- Compliance: How easily the lungs expand; high compliance means easier expansion.
- Airway resistance: Resistance to airflow in airways. Increased airways resistance requires more pressure to produce the same airflow.
Lung Volumes and Capacities
- Tidal Volume (TV): Air inhaled and exhaled in a normal breath; approximately 500 mL.
- Inspiratory Reserve Volume (IRV): Extra air that can be inhaled beyond a normal breath.
- Expiratory Reserve Volume (ERV): Extra air that can be exhaled beyond a normal breath.
- Residual Volume (RV): Air remaining in lungs after maximal exhalation (cannot be measured directly).
- Vital Capacity (VC): Maximum volume of air that can be exhaled after maximum inhalation.
- Inspiratory Capacity (IC): Maximum volume of air that can be inspired after a normal exhalation.
- Functional Residual Capacity (FRC): Volume of air remaining in the lungs after normal exhalation.
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Description
This quiz covers the fundamental concepts of respiratory physiology, including the functions of the respiratory system, pulmonary ventilation, and gas exchange. Students will explore the mechanisms involved in respiration and factors that influence pulmonary ventilation.
