Respiratory L3: Lung Volumes Flashcards
What are 4 factors that determine lung volume?
- Size
- Age
- Gender
- Anatomical build
What is the functional residual capacity?
How much air left in lungs after passive expiration
What is a clinical indicator of functional residual capacity?
Recoil of lungs
- Eg. decreased recoil = increased functional residual capacity
What muscle(s) affect inspiratory reserve volume?
Diaphragm
What muscle (s) affect expiration?
- Abdominals
- External intercostals
What is vital capacity?
The maximum volume of air that can be moved out during a single breath following a maximal inspiration.
- The subject first inspires maximally and then expires maximally (VC = IRV + TV + ERV).
What is the equation for vital capacity?
Vital capacity = Resting tidal + expiratory reserve + inspiratory reserve volume
What is the equation for total lung capacity (TLC)?
TLC = Residual volume (RV) + vital capacity (VC)
What is asthma? What happens to the airways?
Narrowing of smaller airways due to inflamed/thickened inner linings
Why have asthma patients an increased Residual Volume?
Decreased expiratory reserve volume= increased residual volume
What happens in early dynamic airway closure in asthma patients?
Increased small airway resistance –> Increased loss of pressure in small airways –> Early small airway closure, decreased FVC and increased RV
Why have emphysema patients an increased Residual Volume?
Loss of lung tissue
What happens in early dynamic airway closure in emphysema patients?
Loss of lung tissue –> Decreased lung recoil –> Increased intrapleural pressure –> Early small airway closure, decreased FVC and increased RV
What happens to patients who have less compliant lungs?
In restrictive disease the lungs are less compliant and cannot be expanded as normal
- Fibrosis- scar tissue formed in alveoli walls
What happens from the start of when fresh air is inhaled?
What is the effect of dead space volume on exchange of tidal volume between the atmosphere and the alveoli?
Even though 500 mL of air move in and out between the atmosphere and the respiratory system and 500 mL move in and out of the alveoli with each breath, only 350 mL are actually exchanged between the atmosphere and the alveoli because of the anatomic dead space (the volume of air in the respiratory airways).
What are the different breathing patterns on alveolar ventilation?
- Deep, slow breathing- more efficient
- Not hyperventilation- shift air in and out of air
What is the Physiological dead space? How does that related to Ventilation (V) and Perfusion (Q)?
- Amount of air that doesn’t take part in ventilation V/Q > 1
Air is present but blood isn’t flowing (due to constriction of vessels = V>Q)
What is the Physiological shunt? How does that relate to Ventilation (V) and Perfusion (Q)?
- Something constricts airway and air is not present
- Blood is flowing
- Q>V
V/Q <1
Blood is present but air isn’t (due to bronchoconstriction = Q>V)
What is Inspiratory Reserve Volume?
The extra volume of air that can be maximally inspired over and above the typical resting tidal volume.
- The IRV is accomplished by maximal contraction of the diaphragm, external intercostal muscles, and accessory inspiratory muscles.
What is inspiratory capacity (IC)?
The maximum volume of air that can be inspired at the end of a normal quiet expiration (IC = IRV + TV).
What is the Expiratory Reserve Volume?
The extra volume of air that can be actively expired by maximally contracting the expiratory muscles beyond that normally passively expired at the end of a typical resting tidal volume.
What is Residual Volume?
The minimum volume of air remaining in the lungs even after a maximal expiration
What is Functional Residual Volume (FRV)?
The volume of air in the lungs at the end of a normal passive expiration (FRC = ERV + RV)
What is Total Lung Capacity (TLC)?
The maximum volume of air that the lungs can hold
What is Forced expiratory volume in 1 second (FEV1)?
The volume of air that can be expired during the first second of expiration
