Respiratory 4: Ventilation Flashcards
What is the passive force behind expiration and what 2 things contribute to it
Recoil force causes expiration. Elasticity of the lungs and surface tension in the lungs.
What is elasticity of the lung and what is an example of high elasticity and low
Elasticity is the ability to recover original size and shape after deformation.
High elasticity is associated with coming back to its original shape fast -> double balloons
How is elasticity of the lungs generated
The parenchyma tissue surround the alveoli contain elastin and collagen which form a network of springs around the tubes which stretches during inspiration. In expiration is relaxes again during radial traction
What is compliance and its relationship with elasticity
Compliance measures how easy it is to stretch something. It is the change in volume / change in pressure. Compliance is opposite to elasticity. If something is more stiff-> more elastic-> but less compliant
What is surface tension and how does it contribute to the recoil force
Surface tension is the enhancement of intermolecular attractive forces for molecules at the liquid gas interface
What is laplaces law and how does it relate to surface tension
Pressure needed of air to inflate an alveolus is proportional to 2 x the surface tension of surfactant divided by the radius of the alveolus (spherical)
What is laplaces law and how does it relate to surface tension
Pressure needed of air to inflate an alveolus is proportional to 2 x the surface tension of surfactant divided by the radius of the alveolus (spherical)
Explain the consequences of chronic obstructive pulmonary disease (COPD) to ventilation on lung compliance
COPD-> has degradation of lung tissue resulting in loose elastin. As a result, it has a large change in volume over a small change in pressure. Therefore it has increased compliance so overinflates-> inflated at rest so decreases capacity
Explain the consequences of Fibrosis to ventilation on lung compliance
Fibrosis is due to air contaminates causing an increase in collagen fibres= stiff lung. Only a small change in volume over large change in pressure. Therefore it has decreased compliance. This means it can’t get enough air with same amount of pressure
Compare the shape of the lungs, size of the midsternal space and other factors of COPD and Fibrosis
COPD has massively expanded lungs whereas Fibrosis has deflated lungs.
COPD has reduced midsternal space whereas Fibrosis has wide midsternal space
COPD has flattened diaphragm.
Fibrosis has fibrotic tissue
Compare the shape of the lungs, size of the midsternal space and other factors of COPD and Fibrosis
COPD has massively expanded lungs whereas Fibrosis has deflated lungs.
COPD has reduced midsternal space whereas Fibrosis has wide midsternal space
COPD has flattened diaphragm.
Fibrosis has fibrotic tissue
Describe the respiratory airway tree
There is the trachea and the bronchi and then 3 lobes on the right and 2 lobes on the left, covered in parenchyma
What is the funnel effect
The inverse relationship between the resistance of the air and the amount of flow. As well as the inverse relationship between the resistance and cross sectional area
What is the funnel effect in the conducting zone (esp 1’ Bronchi)
The resistance is highest as lowest cross sectional area. As a result has lowest amount of air but highest pressure so fast + turbulent speed
What is the funnel effect in the respiratory zone (esp Alveolar duct)
The resistance is lowest as the cross sectional area is greatest. As a result it has highest amount of air but pressure is lower so slow + laminar speed. (allow time for gas exchange)
