Physiology: Anatomy of chest wall and mechanics of breathing Flashcards
What is Boyle’s Law?
Pressure exerted by a gas is inversely proportional to its volume
Increase volume = Decrease pressure
Decrease volume = Increase pressure
What are the lungs and the interior of the thorax covered by?
Pleural membrane
What pleural membrane covers the outer surface of the lungs?
The visceral pleura
What pleural membrane covers the interior surface of the rib cage?
The parietal pleura
Whats is inflammation of the pleural membrane called?
Pleurisy
What is sticking the lungs and interior of the thorax together?
The pleural fluid
What is trying to the lungs away from the inner rib wall?
The elastic fibres within the lungs
What muscles are used in inspiration?
External intercostal muscles and the diaphragm
What muscles are used in expiration?
Passive at rest
In severe resp load internal intercostal muscles and abdominal muscles
When is the diaphragm relaxed?
After rest expiration and before inspiration
How do the ribs move during breathing?
“bucket handle”motion and moves in a lateral dimension
What is asthma?
Over-reactive constriction of bronchial smooth muscle. Expiration phase is most affected
What happens to airways in inspiration?
Airways are pulled open by physical forces and thoracic volume increases
What happens to airways in expiration?
Airways are compressed by physical forces and thoracic volume decreases
What is intra-thoracic (alveolar) pressure (PA)?
Pressure inside the thoracic cavity
+ve or -ve compared to atmospheric pressure
Inspiration = -ve Expiration = +ve
What is Intra-pleural pressure (Pip)?
Pressure inside the pleural cavity
ALWAYS -ve in healthy lungs
What is the Transpulmonary Pressure (PT)?
Difference between alveolar pressure and the intra-pleural pressure
ALWAYS +ve as Pip is ALWAYS -ve
PT= PA-Pip
What is the important relationship between the pleural membranes?
Sticks the two membranes together as there is a elastic recoil from the chest wall pulling away from lungs and elastic recoil from lungs pulling away from the chest
What happens when closed pleural membrane is opened?
Pneumothorax
What is the relationship between the bulk of air flow between atmosphere and alveoli and pressure and resistance
F=(Patm - PA) / R
