Lecture 25 Flashcards
The mechanics of breathing
what does surfactant do and when is is produced?
it decreases the tension so the alveoli don’t collapse and it made close to birth of the baby
Law of Laplace
P=2T/r
if the tension of 2 bubble are the same, the pressure of the smaller will be greater due to its smaller radius
Why do smaller alveoli have more surfactant?
so its easier for them to inflate
What happens to alveoli pressure when inhaling and exhaling?
it decreases as you inhale and increases as you exhale
What is the pressure of interpleural tissues
Negative and increases negativity as breathing occurs
Why is the pressure of the intrapleural membrane negative?
the visceral membrane is following the lung and the partial tissue is on the chest wall. the lungs always want to be recoiled so when you breathe, the chest pulls the partial away from the lung and the lung pulls in towards itself increasing the negativity (more negative). At rest, the interpleural pressure is -4mmHg
Pneumothorax
A collapsed lung, when air enters the pleural sac, atmospheric pressure is now the same as in interpleural pressure. the chest well expand and the wall inflates.
What happens to volume and pressure during inhalation
the volume increases, decreasing the pressure
What happens to volume and pressure during exhalation?
the volume decreases increasing the pressure
Lung Compliance
the ability for the lung to stretch
What diseases affect lung compliance
fibrotic diseases like making extra collagen because it stiffens the lung
Lung Elastance
ability of the lung to spring back after being stretched?
what disease affect lung elastance
emphysema a loss of elastin tissue
How does muscles move in inspirations
The diaphragm moves down and the eternal intercostal muscle move out increasing the volume of the lung which decree the pressure allowing air to move inside
How does muscles move in expirations
The abdominal muscles and the internal intercostal muscles pulls in by ribs and the diaphragm moves up decreasing the volume and increasing the pressure
