L33 & 34 Flashcards
What is tidal volume (Vt)?
The volume of air entering or leaving the lungs during a single breath. Includes the volumes that fills the alveoli and the what fills the airway.
What is the inspiratory reserve (IRV)?
Additional volume inspired above Vt, used when exercising
What is the expiratory reserve volume (ERV)?
Additional volume expired below Vt.
What is residual volume (RV)?
Volume of gas left in lungs after maximal forced expiration. Cannot be measured by Spirometry
What is inspiratory capacity?
Vt + IRV
What is the functional reserve capacity?
Volume of air in the lungs at the end of normal passive expiration or normal Vt (ERV+ RV)
What is vital capacity? What changes it?
Volume expired after maximal inspiration (IC+ ERV)
- Increases with male gender, increased body size, and physical conditioning.
- Decreases with age
What is total lung capacity?
Sum of all 4 lung volumes. The maximum volume of air that the lungs can hold
What increases the RV/TLC ratio?
Obstructive lung disease (by increasing RV) and restrictive lung disease (by decreasing TLC)
What is forced expiratory volume in one second (FEV1) used for?
To differentiate between lung diseases
How is physiologic dead space calculated?
VD= Vt (PaCO2 - PECO2/ PaCO2)
What is the average diet RQ?
0.8
What produces the intrapleural fluid?
Parietal pleura
What is the function of the conducting zone?
To bring air into and out of the respiratory zone
-Warms, humidifies, and filters air before it reaches gas exchange.
What are the mucous secreting cells?
Goblet cells
What does SNS activation do to airway diameter and resistance?
Increased diameter, decrease resistance
What does PNS activation do to airway diameter and resistance?
Decreased diameter and increased resistance
What is the Ficks law of diffusion?
The amount of gas moving across a tissue is proportional to the area but inversely proportional to its thickness
What are the pores of Kohn?
Pores in the walls of alveoli that allow airflow between adjacent cells.
What are the two types of alveolar cells and what do they do?
- Type 1: wall forming
- Type 2: surfactant producing
What are the two layers that facilitate mucociliary transport?
The sol fluid layer and the gel fluid layer
What regulates the sol fluid layer?
-Regulated by cAMP/calcium chloride channels (CFTR)
What is ciliary dyskinesia?
Recessive genetic disorder that results in defect in gene encoding for dynein, which compromises mucociliary clearance
Typically, forced viral capacity (FVC) is expired in **.
3 seconds
Normally, FEV1/FVC = ***. What does this mean?
0.8
80% of the VC can be forcibly expired in the 1st second
How does fibrosis affect FEV1 and FVC?
It decreases both, however FVC has a greater decrease. Therefore FEV1/FVC is increased.
How does asthma affect FEV1 and FVC?
Both are decreased, however FEV1 has a greater decrease. Therefore, FEV1/FVC is decreased.
What is the difference between anatomic and physiologic dead space?
Anatomic dead space is the conducting zone, physiologic dead space is the total volume of the lungs not participating in gas exchange.
What are the two ways that ventilation relate can be expressed, including the equations.
-Minute ventilation
Minute ventilation = Vt x breaths/min
-Alveolar ventilation:
Alveolar ventilation= (Vt-Vd) x breaths/min
Vd= physiologic dead space
What is the alveolar ventilation equation?
Va= (VCO2 x K)/ PACO2
VCO2= rate of CO2 production
What does increased alveolar ventilation mean for PACO2?
It is decreased.
What happens to alveolar ventilation when CO2 production is doubled?
It must also double and the curve shifts to the right
What are the two alternate methods to measure FRC since it cannot be measured by spirometry?
-Helium dilution and body plethysmograph
