3 Ventiliation Flashcards
Q: Describe the movement of normothermic ex vivo ventilated perfused lungs. (2)
A: There is no restriction to the movement and so they expand freely in all directions
The movement is not limited by the chest wall
Q: Define minute ventilation.
A: The volume of air expired in one minute (VE) or per minute (V̇E).
Q: Define respiratory rate (RF).
A: The frequency of breathing per minute
Q: Define alveolar ventilation (Valv).
A: The volume of air reaching the respiratory zone
Q: Define respiration.
A: The process of generating ATP either with an excess of oxygen (aerobic) and a shortfall (anaerobic)
Q: Define anatomical dead space.
A: The capacity of the airways incapable of undertaking gas exchange
Q: Define alveolar dead space.
A: Capacity of the airways that should be able to undertake gas exchange but cannot (e.g. alveoli that are not perfused or have collapsed within the respiratory zone)
Q: Define physiological dead space. (2) Normal value? Depends on?
A: Equivalent to the sum of alveolar and anatomical dead space
In most healthy individuals, the alveolar dead space is zero and hence the physiological dead space is more or less equal to anatomical dead space
Normal physiological dead space = 150 mL
This varies depending on the size of your conducting zone
Q: Define hyperventilation,
A: Excessive ventilation of the lungs atop of metabolic demand (results in reduced PCO2 - alkalosis)
Q: Define hypoventilation.
A: Deficient ventilation of the lungs; unable to meet metabolic demand (increased PO2 – acidosis)
Q: Define hyperpnoea.
A: Increased depth of breathing (to meet metabolic demand)
Q: Define hypopnoea.
A: Decreased depth of breathing (inadequate to meet metabolic demand)
Q: Define apnoea.
A: Cessation of breathing (no air movement)
Q: Define dyspnoea.
A: Difficulty in breathing
Q: Define bradypnoea.
A: Abnormally slow breathing rate
Q: Define tachypnoea.
A: Abnormally fast breathing rate
Q: Define orthapnoea.
A: Positional difficulty in breathing (when lying down)
Q: What are the components of the chest wall? Describe the recoil property of them.
A: TWO components to the chest wall:
- Bone + muscle + fibrous tissue
- Lungs
- the rib cage would naturally recoil outwards
- tThe lungs have a tendency to recoil INWARDS
Q: What is functional residual capacity (FRC)? How? Marked by?
A: At the end of that tidal expiration you’re at FRC where the rib cage and the lungs are in equilibrium.
The elastic recoil of the lungs inwards and the outward recoil of the rib cage are IN EQUILIBRIUM
end of a tidal breath marks the Functional Residual Capacity (FRC)
Q: When the lungs and ribcage are in equilibrium, what do you need to cause movement in either direction?
A: muscular effort to push the equilibrium in one direction or the other
Q: What is the pleural cavity? Pressure?
A: (space in between parietal and visceral pleura) is of a FIXED VOLUME and contains protein-rich pleural fluid
The pleural cavity is at negative pressure
Q: What links the lungs and the chest wall?
A: When we think about changing pressures, the pleural cavity is going to be the link between the lungs and the chest wall
Q: How do we do a full inspiration? (including diaphragm, lung, pleural cavity, chest wall)
A: If we do a full inspiration, we will be expanding the chest wall as well as pulling the diaphragm down
So the chest wall needs to pull the lung with it (though they aren’t physically attached) - the negative pressure of the pleural cavity allows the chest wall to pull the lungs with it