HLK Week 3 Flashcards
Definition of ventilation:
Movement of air between alveoli and atmosphere by BULK FLOW. A mechanical process.
Definition of respiration:
Movement of gases into and out of the body. Ventilation is part of the process but not exactly synonymous with it. Not to be confused with cellular respiration.
Discuss anatomical vs. physiological dead space:
Anatomical:
- Refers to the amount of air that is always left inside the airways. Must be subtracted from tidal volume to obtain true alveolar ventilation.
Physiological:
- Refers to the amount of air that reaches the alveoli but which doesn’t participate in gas exchange because, e.g., of non-uniform capillary distribution in the alveoli.
What does immediate orthopnea in an otherwise “healthy” person indicate?
Bilateral diaphragmatic weakness or paralysis
Define trepopnea:
Dyspnea only in a lateral decubitus position
Define platypnea:
Dyspnea only in an upright position
What is the definition of ventilation/perfusion (V/Q) ratio?
The ratio of the amount of air reaching the alveoli (ventilation) to the amount of blood reaching the alveoli (perfusion).
What is the classic imaging finding in a patient with acute hemoptysis?
Ground glass appearance on CXR
What’s the mechanism of action of albuterol and other SABA drugs?
Stimulates beta 2 receptors, relaxing bronchial smooth muscle and promoting bronchodilation.
According to lecture, what are the recommendations for theophylline?
Not recommended. Does not appear to control asthma but may be prescribed due to affordability.
Discuss restrictive vs. obstructive diseases in regards to vital capacity and the FEV1 test:
Restrictive:
- Not due to airway narrowing but rather lung expansion
- Therefore, normal FEV1 but decreased vital capacity
Obstructive:
- Due to airway narrowing
- Therefore normal vital capacity but reduced FEV1
The most common reason for inadequate oxygen movement between alveoli and capillaries:
Ventilation/perfusion inequality:
- Some alveoli may not be adequately ventilated, despite adequate blood supply (e.g., alveolar collapse)
- Some alveoli may be well ventilated but w/o adequate blood supply (e.g., due to a clot)
Which is more affected by V/Q mismatch, O2 or CO2 transfer?
O2
The neurons of the dorsal respiratory group (DRG) are responsible for which phase of respiration?
Inspiration
What is the function of the ventral respiratory group (VRG) on respiration?
- Cells of the respiratory rhythm generator are located in the pre-Botzinger complex in the VRG. They set the basal respiratory rate.
- VRG neurons also control active expiration.