Respiration Flashcards
(16 cards)
What is tidal volume (VT)?
The volume of air moved in or out of the lungs during a normal breath.
What is anatomical deadspace?
The volume of air in the respiratory passages (nose, throat, trachea, bronchi) that does not participate in gas exchange.
What is physiological deadspace?
The total volume of the lungs that does not participate in gas exchange, including both anatomical and alveolar deadspace.
Why doesn’t gas exchange occur in the deadspace?
Because the surfaces of the airways are not suitable for gas exchange with blood.
What is the alveolar volume (VA)?
The portion of air that reaches the alveoli and participates in gas exchange.
What is expired air (VEA)?
A mixture of air from alveolar regions and the deadspace, collected during exhalation.
What is the Bohr equation used for?
To calculate the volume of deadspace using tidal volume and gas concentrations.
What is the Bohr equation for deadspace volume (VD)?
VD = VT × (CO₂A - CO₂E) / CO₂A
In the Bohr equation, what do CO₂A and CO₂E represent?
CO₂A: Alveolar CO₂ concentration
CO₂E: Expired (mixed) CO₂ concentration
What is the assumption about CO₂D (deadspace CO₂ concentration)?
It is assumed to be negligible (≈ 0%).
What are the units for VT, VD, and VEA?
Millilitres (ml)
How is tidal volume (VT) calculated from minute ventilation and breathing rate?
VT = Minute ventilation / Breathing rate
How do you measure gas concentration in alveolar air?
By collecting the last portion of exhaled air after a forced expiration using a syringe and analyzing it.
What does the Servomex gas analyzer measure?
Oxygen and carbon dioxide concentrations in air samples.
What is the function of the BIOPAC system in this practical?
To record tidal volume, expired air volume (Ve), and gas concentrations during breathing.
How do you calculate breathing rate from a Biopac trace?
Count the number of breaths in a 30s interval and multiply by 2.
