Mechanics of Breathing and Ventilation Flashcards
What muscles are active during forced inspiration?
Sternocleidomastoid
Scalenes
What is transpulmonary pressure?
The difference between the alveolar pressure and the pleural pressure. Larger during inspiration and lower during expiration.
During inspiration, the volume of the lungs increases. What effect does this have on airway resistance?
Decreases resistance
The smaller an alveoli is, the […] likely it is to collapse.
More
What is the effect on airway resistance of stimulation of beta 2 adrenergic receptors (activated by sympathetic NS)?
Airway dilation –> decreased resistance
How does the anatomy of the lungs help overcome airway resistance?
The airways are arranged in parallel to reduce resistance (just like electrical circuit)
Laminar flow of air occurs in […] airways
Small
What is compliance?
The ability of the lung to be stretched (change in volume) allowing for a change in pressure
What is the compliance of the:
- Lungs
- Chest wall
- Respiratory Sytem
- 200 mL / cm H2O
- 200 mL / cm H2O
- 1/200 + 1/200 = 2/200 = 1/100 –> 100 mL / cm H2O
- Total lung compliance is less than individual compliance of the lungs or chest wall
- Alveolar pressure is […] during inspiration and […] during expiration
- Intrapleural pressure is always […]
- Transpulmonary pressure is always […]
- Negative; Positive
- Negative
- Positive
The flow of air in the trachea is […]
Turbulent
Airway resistance is directly proportional to the length of the airway and inversely proportional to the r4 of the airway. Thus, as radius decreases, resistance increases. What is the clinical signficance of this statement?
Diseases like asthma and bronchitis more heavily affect airways that have high resistance
With respect to lung capacity:
- What is the tidal volume?
- What is the expiratory reserve volume?
- What is the residual volume
- What is functional residual capacity?
- The baseline volume of air that is inspired and expired with each cycle of normal breathing
- The extra volume of air that you could force out with effort that exceeds that of normal breathing
- The extra volume of air that you cannot force out of your lungs no matter how hard you try
- FRC = ERV + RV
What effect does kyphosis and pulmonary fibrosis have on respiratory compliance?
Kyphosis: decrease chest wall compliance
Pulmonary fibrosis: decrease lung compliance
What muscles are active during normal expiration?
TRICK QUESTION - normal expiration is passive