Lecture 3 Flashcards
What is hysteresis
Loss of energy
How is something stretched or distorted
When it is subjected to a force
What causes recoil pressure
Elastic recoil and its elastance
On inhalation what happens to intrapleural pressure
Lowers the pressure
Is intrapleural pressure positive or negative compared to ATM and alveoli
Negative
What happens in pneumothorax
There is a hole between the ATM or alveoli and intrapleural space, te pressure surrounding the lung will rise causing it to collapse
What is static lung compliance
Measurement of how easy the lungs can be stretched at rest
What is dynamic lung compliance
Measurement of stretchiness during breathing
What happens in lung fibrosis
Stiffened by laying down of collagen and fibrin. Compliance is reduced
What happens in emphysema
Parenchyma of lung is destroyed. Less elastic recoil and compliance is increased
Why is it that children’s lungs get problems
Deficiency of surfactant
What is an endochondral tube
Tube used for mechanical ventilation
What effect does artificial surfactant have
Reduces surface tension in alveoli stabilising them and increasing lung compliance
If a lung is filled with water how much easier is it to inflate
2x as easy
How does a skin of a liquid exist
Due to an imbalance of forces on the surface molecules
What does the skin of liquid seek
Entropy
If alveoli were only line with interstitial fluid pressure would have to be
3kPa
Surfactant can be obtained by
Bronchial lavage
Is surface tension and elastic recoil is reduced does it make it harder to breathe
Makes breathing easier
How is surfactant made up
Phosphatidylcholine
Choline head
Phosphate neck
Triglyceride shoulders
Polyunsaturated fatty acid chains
Compliance rule
Change in volume
___________________
Change in pressure
What is the lung compliance of a normal male
2L/kPa
Because lung compliance varies in sex and size how do we measure it
Specific lung compliance
How don’t the lungs fully empty on expiration
As the thorax is flighty pulled out as the thoracic cage holds the
Total compliance rule
Total compliance =
Lung compliance + wall compliance
Name 5 factors affecting lung compliance
- Lung size
- Recent pattern of breathing
- Age
- Posture
- Disease
What is compliance
Ability of the lungs to stretch in volume when pressure is applied
