58 Questions
What are the two phases of pulmonary ventilation?
Inhalation and exhalation
Which physical properties of the lungs influence ventilation?
Compliance, elasticity, and surface tension
What is the pressure in the intrapleural space?
Subatmospheric
How are the lungs expanded and contracted during respiration?
By movement of the diaphragm and elevation or depression of the ribs
What are the pressure differences induced by changes in lung volumes?
Transpulmonary pressure
What influences ventilation besides lung physical properties?
Chest wall compliance and diaphragm strength
What is the main function of surfactant in the alveoli?
To assist in keeping the alveoli open by reducing surface tension
What is the most common cause of respiratory distress syndrome (RDS) in neonates?
Inadequate production of surfactant
What happens to pleural pressure during normal inspiration?
It decreases
What role does transpulmonary pressure play during inspiration?
It keeps the lungs against the chest wall
What does alveolar ventilation refer to?
The renewal of air in the gas exchange areas of the lungs
What is the main function of mucociliary escalation in the respiratory passages?
To keep the respiratory passages moist and remove inhaled particles
What is the function of the mucus in the respiratory passages?
Trapping small particles from the inspired air
What is the direction of the 'power stroke' of the cilia in the lungs?
Upward, toward the pharynx
What is the tidal volume for an average healthy man?
500 ml
What is the volume of air remaining in the lungs after the most forceful expiration?
Residual volume (≈ 1200 ml)
Which pulmonary capacity represents the amount of air that remains in the lungs at the end of a normal expiration?
Functional residual capacity (≈2300 ml)
What is a key measurement used when assessing pulmonary function?
Forced expiratory volume in 1 sec (FEV1)
In which disease is it usually much more difficult to expire than to inspire?
Asthma
What is measured using a technique known as spirometry?
Pulmonary function
What is the main factor influencing ventilation besides lung physical properties?
Transpulmonary pressure
During normal inspiration, what happens to the volume of the thorax and lungs?
They increase
What function does surface tension in the alveoli serve in relation to ventilation?
It prevents alveolar collapse
What is the volume of air inspired or expired with each normal breath in an average healthy man?
3500 ml
Which measurement is useful diagnostically and known as a pulmonary function test?
Forced expiratory volume in 1 sec (FEV1)
What represents the maximum amount of air a person can expel from the lungs after first filling the lungs to their maximum extent and then expiring to the maximum extent?
Vital capacity
In which lung disorder is the volume and vital capacity reduced to below normal, while FEV1 remains normal?
Pulmonary fibrosis
What is the primary role of surfactant in the alveoli?
Reducing the surface tension of water in the alveoli
What is the effect of a pneumothorax on the intrapleural pressure?
Intrapleural pressure increases due to the buildup of air
What role does transpulmonary pressure play during inspiration?
It keeps the lungs against the chest wall
What physical properties of the lungs influence ventilation?
Compliance, elasticity, and surface tension
What is the primary function of surfactant in the alveoli?
Reducing surface tension and preventing alveolar collapse
What is the effect of a pneumothorax on the intrapleural pressure?
It decreases the intrapleural pressure
What represents the maximum amount of air a person can expel from the lungs after first filling the lungs to their maximum extent and then expiring to the maximum extent?
Vital capacity
In which lung disorder is it usually much more difficult to expire than to inspire?
Obstructive lung disease
What is measured using a technique known as spirometry?
Forced expiratory volume in 1 second (FEV1)
What is the anatomical dead space volume in the conducting airways?
Around 350 ml
What is the maximum volume of air a person can breathe in after a normal expiration and distending the lungs to the maximum amount?
About 3500 ml
Which lung disorder is characterized by an increase in airway resistance due to bronchoconstriction and obstruction by mucus?
Asthma
What measurement represents the maximum amount of air a person can forcefully exhale after a maximum inhalation?
Vital capacity
Which lung disease causes severe airway obstruction and makes it much more difficult to expire than to inspire?
Asthma
What is the volume of air remaining in the lungs at the end of a normal expiration?
About 2300 ml
Which measurement is useful diagnostically and represents the fraction of the total 'forced' vital capacity expired in 1 sec?
Forced expiratory volume in 1 sec (FEV1)
What represents the maximum volume to which the lungs can be expanded with the greatest possible effort?
Total lung capacity
What occurs when a person expires with great force, and the expiratory airflow reaches a maximum flow beyond which it cannot be increased anymore even with greatly increased additional force?
Measurement of Maximum Expiratory Flow
What represents the amount of air inspired or expired with each normal breath in an average healthy man?
Tidal volume
What is classified as a restrictive lung disorder characterized by reduced volume and capacities (vital capacity) below normal, while FEV1 remains normal?
Pulmonary fibrosis
What measurement is used to assess pulmonary function and provide important diagnostic information about lung function?
Forced expiratory volume in 1 sec (FEV1)
What is the role of surfactant in the alveoli?
To prevent the collapse of the alveoli during expiration
What happens to intrapleural pressure during a pneumothorax?
It increases due to the entry of air into the pleural space
What is the primary influence on transpulmonary pressure during inspiration?
Expansion of the chest cage
What term refers to the pressure difference between that in the alveoli and that on the outer surfaces of the lungs?
Transpulmonary pressure
What is the main function of mucociliary escalation in the respiratory passages?
To trap foreign particles and pathogens
What occurs to pleural pressure during normal expiration?
It increases (becomes less negative)
Which measurement represents the amount of air inspired or expired with each normal breath?
Tidal volume
What represents the maximum amount of air a person can expel from the lungs after first filling them to their maximum extent?
Vital capacity
What is alveolar ventilation?
The rate at which new air reaches gas exchange areas of the lungs
What represents a key measurement used when assessing pulmonary function?
Spirometry
Study Notes
Pulmonary Ventilation
- The two phases of pulmonary ventilation are inspiration and expiration.
- Physical properties of the lungs that influence ventilation include lung compliance, surface tension, and airway resistance.
Pressure and Ventilation
- The pressure in the intrapleural space is negative, approximately -5 mmHg.
- During respiration, the lungs are expanded and contracted by changes in intrapleural pressure.
- Pressure differences induced by changes in lung volumes include:
- Inspiratory pressure difference: -5 mmHg to -10 mmHg
- Expiratory pressure difference: +5 mmHg to +10 mmHg
Surfactant and Mucociliary Escalation
- The main function of surfactant in the alveoli is to reduce surface tension, allowing for easier expansion and preventing collapse.
- The function of mucociliary escalation in the respiratory passages is to remove mucus and debris from the airways.
- The direction of the 'power stroke' of the cilia in the lungs is towards the throat.
Lung Volumes and Capacities
- The tidal volume for an average healthy man is 500 mL.
- The volume of air remaining in the lungs after the most forceful expiration is the residual volume (RV).
- The functional residual capacity (FRC) represents the amount of air that remains in the lungs at the end of a normal expiration.
Pulmonary Function Tests
- A key measurement used when assessing pulmonary function is forced vital capacity (FVC).
- Spirometry is a technique used to measure lung volumes and capacities.
- The primary function of pulmonary function tests is to diagnose and monitor lung disorders.
Respiratory Distress Syndrome (RDS) and Lung Disorders
- The most common cause of RDS in neonates is a deficiency of surfactant.
- In chronic obstructive pulmonary disease (COPD), it is usually much more difficult to expire than to inspire.
- The primary function of surfactant in the alveoli is to reduce surface tension, allowing for easier expansion and preventing collapse.
- In restrictive lung disorders, such as pulmonary fibrosis, volume and vital capacity are reduced to below normal, while FEV1 remains normal.
Other Key Facts
- The effect of a pneumothorax on the intrapleural pressure is to increase it to atmospheric pressure.
- The primary influence on transpulmonary pressure during inspiration is the contraction of the diaphragm and intercostal muscles.
- The term that refers to the pressure difference between that in the alveoli and that on the outer surfaces of the lungs is transpulmonary pressure.
- During normal inspiration, the volume of the thorax and lungs increases.
- Surface tension in the alveoli serves to increase the effort required to expand the lungs during inspiration.
Test your knowledge of respiratory mechanics, lung capacities, and volumes with this quiz. Explore topics such as the elastic nature of the lungs and chest wall, intrapleural pressure, and the phases of pulmonary ventilation.
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