59 Questions
What is the primary difference between air flow in the respiratory system and blood flow in the circulatory system?
Air is less viscous and compressible, while blood is non-compressible
What creates pressure gradients for the flow of air in the respiratory system?
A muscular pump
What is the primary influence on resistance to air flow in the respiratory system?
The diameter of the tubes through which air is flowing
What does external respiration involve?
The exchange of air between the atmosphere and the lungs
Which gas composition primarily mediates bronchiole diameter?
Carbon dioxide
What gas composition causes pulmonary arteries to dilate?
Carbon dioxide
What gas composition causes systemic arteries to dilate?
Oxygen
What gas composition causes bronchioles to constrict?
Carbon dioxide
Which gas composition increases during bronchiole constriction?
Carbon monoxide
What gas composition decreases during systemic artery constriction?
Oxygen
What gas composition increases during systemic artery constriction?
Carbon dioxide
What is the primary mediator of bronchiole diameter?
Carbon dioxide levels
What are the lung volumes measured using a spirometer?
Tidal volume, inspiratory reserve volume, expiratory reserve volume, and residual volume
What is responsible for maintaining alveolar stability and decreasing the work of breathing?
Surfactant
What keeps the lungs inflated by maintaining subatmospheric pressure in the pleural cavity?
Subatmospheric pressure in the pleural cavity
What are the components of lung capacity?
Vital capacity and total lung capacity
What are the factors affecting airway resistance?
Airway diameter, bronchoconstriction, and bronchodilation
What determines the efficiency of breathing?
Rate and depth of breathing
What is responsible for stretching and returning the lungs to resting volume?
Lung compliance and elastance
What are the components of lung volumes?
Tidal volume, inspiratory reserve volume, expiratory reserve volume, and residual volume
When does inspiration occur during ventilation?
When alveolar pressure decreases
When does expiration occur during ventilation?
When alveolar pressure increases
What are the measures of breathing efficiency?
Total pulmonary ventilation and alveolar ventilation
What changes during quiet breathing are illustrated in Figure 17.9?
Pressure changes
Which part of the respiratory system is responsible for warming, humidifying, and filtering inspired air?
Nasal cavity
Where does gas exchange, allowing oxygen to move from inhaled air to blood and carbon dioxide to move from blood to exhaled air, primarily occur?
Alveoli
What surrounds the lungs and aids in respiration?
Thoracic cage
Which structure holds the lungs against the thoracic wall and contains pleural fluid to lower friction?
Double-walled pleural sac
What is the site of gas exchange in the respiratory system?
Alveoli
Which cells in the alveoli facilitate rapid gas exchange and produce surfactant to prevent alveolar collapse?
Type I and type II alveolar cells
What characterizes the pulmonary circulation?
High flow and low pressure
Which gas laws describe pressure-volume relationships and the contribution of different gases in humid air to the total pressure?
Dalton's law and Boyle's law
What is crucial for understanding gas exchange in the respiratory system, at different temperatures and humidities?
Partial pressures of atmospheric gases
What must be considered when calculating the partial pressure of a gas in humid air?
Water vapor pressure
What are essential factors in understanding gas exchange in the respiratory system?
Atmospheric pressure, gas mixtures, and the role of water vapor in humid air
During gas exchange between alveoli and blood, which of the following is true?
PO2 alveolar air > PO2 blood
What is the normal range for partial pressure of oxygen (PO2) in arterial blood?
95 mm Hg (85–100)
What characterizes the pulmonary circulation?
Low resistance and high compliance
What is the normal range for pH in arterial blood?
7.4 (7.38–7.42)
Where are the peripheral chemoreceptors located?
In carotid bodies
What triggers an increase in ventilation?
Decrease in PO2, increase in pH, and increase in PCO2
Where are the central chemoreceptors located?
In CNS
What happens if tidal volume exceeds a certain volume?
Stretch receptors signal brain stem to terminate inspiration
What part of the brain can affect the control of breath rate and depth?
Cerebrum and hypothalamus
What part of the brain cannot override chemoreceptor reflexes?
Limbic system
What do the protective reflexes guard the lungs against?
Physical injury or irritation and over inflation
What is the primary role of the carotid body cells?
Respond to PO2 below 60 mm Hg
What factors affect oxygen-hemoglobin binding?
Changes in plasma pH, temperature, and PCO2
What influences oxygen-hemoglobin binding?
The Bohr effect and 2,3-bisphosphoglycerate (2,3-BPG) production
How is carbon dioxide primarily transported in the blood?
As bicarbonate ions
What enzyme converts CO2 to bicarbonate ions in RBCs?
Carbonic anhydrase
Which cells control breathing in the medulla?
Dorsal and ventral respiratory groups
What acts as a central pattern generator for controlling inspiratory and expiratory muscles?
Neural networks in the brainstem
How is CO2 primarily removed from the lungs?
By diffusion down the PCO2 gradient from blood to alveoli
What enhances fetal hemoglobin's ability to bind oxygen in low-oxygen environments?
Its structure
What maintains electrical neutrality during CO2 transport in RBCs?
Chloride shift
What plays a role in continuous modulation of ventilation?
Chemoreceptor- and mechanoreceptor-linked reflexes and higher brain centers
What does gas movement in alveoli depend on?
Pressure gradient, gas solubility in liquid, and temperature
What picks up maximum oxygen possible under normal conditions in the blood?
Hemoglobin
Study Notes
Respiratory System Anatomy and Function
- The respiratory system includes the upper and lower airways, such as the mouth, nasal cavity, pharynx, larynx, trachea, bronchi, and lungs.
- The alveoli are the site of gas exchange, allowing oxygen to move from inhaled air to blood and carbon dioxide to move from blood to exhaled air.
- The thoracic cage, including the bones and muscles of the thorax and abdomen, surrounds the lungs, with the diaphragm, intercostal muscles, and other muscles aiding in respiration.
- The lungs are light, spongy organs with a double-walled pleural sac that holds them against the thoracic wall and contains pleural fluid to lower friction.
- The airways warm, humidify, and filter inspired air to protect the delicate alveoli and ensure efficient gas exchange.
- Alveoli are the site of gas exchange, with type I and type II alveolar cells facilitating rapid gas exchange and producing surfactant to prevent alveolar collapse.
- The pulmonary circulation is characterized by high flow and low pressure, with blood flow through the lungs equal to that through the rest of the body.
- Gas laws, including Dalton's law and Boyle's law, describe pressure-volume relationships and the contribution of different gases in humid air to the total pressure.
- The partial pressures of atmospheric gases at different temperatures and humidities are crucial for understanding gas exchange in the respiratory system.
- O2 and CO2 partial pressures in dry and humid air at different temperatures are necessary for calculating the partial pressure of a gas in humid air.
- Water vapor pressure in humid air must be considered when calculating the partial pressure of a gas, as it dilutes the contribution of other gases to the total pressure.
- Atmospheric pressure, gas mixtures, and the role of water vapor in humid air are essential factors in understanding gas exchange in the respiratory system.
Factors Affecting Gas Exchange and Hypoxia
- Gas movement in alveoli is proportional to pressure gradient, gas solubility in liquid, and temperature.
- Gas entering capillaries first dissolves in plasma; hemoglobin picks up maximum oxygen possible under normal conditions.
- Several factors affect oxygen-hemoglobin binding, including changes in plasma pH, temperature, and PCO2.
- The Bohr effect and 2,3-bisphosphoglycerate (2,3-BPG) production influence oxygen-hemoglobin binding.
- Fetal hemoglobin's structure enhances its ability to bind oxygen in low-oxygen environments.
- Carbon dioxide is transported in plasma, diffused into RBCs, bound to hemoglobin, or converted to bicarbonate ions.
- Carbonic anhydrase in RBCs converts CO2 to bicarbonate ions; chloride shift maintains electrical neutrality.
- Hemoglobin's interaction with H+ and CO2 affects its binding affinity for oxygen.
- CO2 is removed from the lungs by diffusion down the PCO2 gradient from blood to alveoli.
- Neural networks in the brainstem act as a central pattern generator, controlling inspiratory and expiratory muscles.
- Continuous modulation of ventilation occurs through chemoreceptor- and mechanoreceptor-linked reflexes and higher brain centers.
- Neurons in the medulla control breathing, with the dorsal and ventral respiratory groups playing different roles.
Test your knowledge of the respiratory system's anatomy and function with this quiz. Explore the key components, such as the airways, alveoli, and pulmonary circulation, as well as the principles of gas exchange and the influence of atmospheric pressure and gas mixtures. Perfect for students and professionals in healthcare and biology.
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