Respiratory Physiology (Law Of Laplace) Flashcards
What is surfactant?
Detergent like fluid produced by Type II Alveolar cells
What is the role of surfactant?
Reduces surface tension on alveolar surface membrane
thus reducing tendency for alveoli to collapse
What is surface tension?
surface tension occurs where ever there is an air- water interface and refers to the attraction between water molecules
What is the alveolar sac covered in?
Water molecules
Why does air need to be saturated in the lungs?
The body needs enough oxygen to keep the blood adequately saturated, so that cells and tissues get enough oxygen to function properly.
Keep lungs inflated
Why is it important for alveolar type II cells to produce surfactant?
Increase lung compliance and less recoil to over come, making inspiration easier
Are water molecules attracted to one another?
Yes
Is surfactant more effective in small or large alveoli?
Small
Why is surfactant more effective in small alveoli?
because surfactant molecules come closer together and are therefore more concentrated.
Is surfactant more numerous in small or large alveoli?
Small
Want to maintain surface area for gas exchange
Do small alveoli have greater surface tension compared to large alveoli?
Yes, hence why more surfactant is required to compensate for this
Why is the pressure greater is smaller alveoli?
Same surface tension but smaller radius, creates a higher pressure in smaller alveoli
When does surfactant production begin?
Around 25 weeks
When is surfactant production completed during pregnancy?
Around 36 weeks
What stimulated surfactant production?
Thyroid hormones and cortisol
What can premature barbarise suffer from?
Premature babies suffer Infant Respiratory Distress Syndrome (IRDS).
What is compliance?
change in volume relative to change in pressure
i.e. how much does volume change for any given change in pressure
What does compliance represent?
It represents the stretchability of the lungs (not the elasticity!)
What is healthy lungs with regards to compliance?
large increase in lung volume for small decrease in ip pressure
What is low compliance?
small increase in lung volume for large decrease in ip pressure
What is emphysema?
a lung disease that results from damage to the walls of the alveoli in your lungs. Not high elasticity, Ned to put in effort for expiration.
High lung compliance but low elasticity
What disease is low compliance associated with?
COPD
