Ventilation and Compliance Flashcards
State some functions of surfactant.
- Reduces surface tension on alveolar surface membrane, reducing chance of alveoli collapse
- Reduces lungs’ tendency to recoil
- Increases lung compliance
What is compliance?
Change in volume relative to change in pressure. High compliance means a high change in volume for a small decrease in intrapleural pressure.
Where is the greatest amount of compliance?
Base of the lung. Gravity innit; alveoli at the bottom are compressed more so have greater opportunity to expand
List some obstructive lung diseases.
Asthma
COPD -Chronic bronchitis
-Emphysema
What causes emphysema?
Lack of elastic recoil caused by
List some restrictive lung diseases.
Pneumothorax Oedema Infant respiratory distress syndrome Fibrosis Loss of lung compliance
Describe the function of spirometry
Commonly used to measure lung function
Can give static recordings where you only take the volume inhaled or exhaled
Can give dynamic readings where volume inspired and expired over a certain time is given
What are the meanings of FEV and FVC
FEV - Forced Expiratory Volume
FVC - Forced Vital Capacity
Describe pulmonary ventilation.
Total air ventilation in/out of lungs. (L/min)
Describe alveolar ventilation.
Fresh air entering alveoli available for gas exchange. (L/min)
What value is given for normal alveolar ventilation?
4.2 L/min
What are the approximate values for PO2 and PCO2 during normal ventilation?
PO2 - 13.3 kPa, 100 mmHg
PCO2 - 5.3 kPa, 40 mmHg
Give some examples of restrictive lung diseases and briefly describe them.
Asthma Emphysema (destruction of alveoli and loss of elasticity)
Give some examples of obstructive lung diseases and briefly describe them.
COPD (Chronic obstructive pulmonary disease)
FVC decreased as well as FEV
What is the difference between obstructive and restrictive diseases?
Obstructive - Blocks airways
Restrictive - Restricts lungs expanding
