Lectures 3 and 4: Respiratory Flashcards
Fibrosis lung compliance
Decreased
Fibrosis impact on expiratory volume
Volume present in the lungs after expiring a breath would be less than normal
Emphysema impact on lung compliance
Increased
Emphysema is a disease involving which fibers in lungs?
Elastic
Emphysema impact on expiratory volume
Volume present in lungs after expiring a breath would be more than normal
Functional residual capacity
Resting, or equilibrium, volume of the combined lung and chest wall system
Emphysema FRC impact
Increased
Fibrosis FRC impact
Decreased
What is lung compliance
Volume/Pressure; the ability of the lungs to stretch and expand
In an air filled lung, how does alveolar pressure compare to atmospheric pressure?
Equal
As the pressure outside the lung is made more negative the lung…
Inflates and its volume increases
What is the expanding pressure for the lungs?
Negative outside pressure (intrapleural space)
Lung hysteresis
Lung volume at any given pressure during inhalation is less than the lung volume at any given pressure during exhalation
The intrapleural space normally has a ______ pressure
Negative
The negative intrapleural pressure is caused by which 2 things
The elastic properties of:
The lungs
The chest wall
What prevents the lungs from collapsing and the chest wall from springing out?
Negative intrapleural pressure
Pneumothorax definition
When sharp object punctures intrapleural space, air is introduced in the space, and intrapleural pressure becomes zero
What are the two consequences of pneumothorax?
Lungs collapse
Chest wall springs out
Atelectasis definition
Lung/alveoli collapse
What is atelectasis due to?
No surfactant, so small alveoli have increased surface tensions and pressures and collapse
Parasympathetic stimulation causes what to resistance of air flow?
Increase
Sympathetic stimulation causes what to resistance to air flow?
Relaxation
Surfactant defintion
A mixture of phospholipids that line the alveoli and reduce their surface tension. By reducing surface tension, surfactant reduces the collapsing pressure for a given radius
What about surfactant makes it decrease surface tension in the alveoli?
The attractive forces between adjacent molecules of liquid are strong than the attractive forces between molecules of liquid and molecules of gas in alveoli
Three phases of the breathing cycle
Rest
Inspiration
Expiration
What is rest specifically?
Period between breathing cycles where the diaphragm is at its equilibrium position
There is no air flow at rest because there is no pressure between what?
The atmosphere (mouth or nose) and alveoli
Alveolar pressure at rest =
Atmospheric pressure
Volume present at rest is known as the
Equilibrium aka FRC
Inspiration actions
Diaphragm contracts, volume of thorax increases
As lung volume increases during inspiration, pressure
Decreases
Halfway through inspiration, what happens to alveolar pressure compared to atmospheric pressure?
Alveolar pressure falls below atmospheric pressure
What drives air flow into the lung during inspiration?
The pressure gradient between the atmosphere and the alveoli
When does air stop flowing into the lung?
Alveolar pressure equals atmospheric pressure, so no more pressure gradient
During inspiration, what happens to intrapleural pressure?
Becomes even more negative than at rest
During inspiration, what happens to alveolar and airway pressures?
Become negative
Expiration is active or passive
Passive process
What happens to alveolar pressure during expiration?
Becomes positive and higher than atmospheric pressure
Why does alveolar pressure increase during expiration?
Elastic forces of the lungs compress the greater volume of air in the alveoli
Hyperventilation definition
Increase breathing frequency and volume
What impact does hyperventilation have on PaCO2?
Decreases
What does the decrease of PaCO2 during hyperventilation do to arterial pH?
Causes arterial pH to increase
Hypoventilation definition
Decrease in breathing frequency in volume
Since hyperventilation will produce unconsciousness and person’s breathing will eventually return to normal, it is
Self-limiting
Ventilation definition
Flow of air into and our of alveoli
Hypoventilation causes what in PaO2 and PaCO2
Decrease in PaO2 and increase in PaCO2
Apnea definition
Temporary cessation of breathing; typically during sleep
Eupnea definition
Normal, relaxed breathing. Healthy condition of inhalation and relaxation
Tachypnea definition
Respiratory rate that is greater than the normal for age
Hyperpnea definition
Increased volume with or without an increase rate of breathing
Hypopnea definition
Taking shallow breaths for 10 seconds or long while asleep
Bradypnea definition
Breathing more slowly than normal
Orthopnea definition
Shortness of breath or difficulty breathing when you’re lying down
Diffusion-limited gas exchange definition
Means total amount of gas transported across the capillary barrier is limited by the diffusion process
Perfusion-limited gas exchange
Means total amount of gas transported across the alveolar-capillary barrier is limited by blood flow through the pulmonary capillaries
