Respiration Lecture 8 Flashcards
Two zones of the lungs anatomically
Conducting zone: trachea to 16th split
anatomical dead space
Respiratory zone: 17th split to alveolae
terminal respiratory unit found here
Tidal Volume: definition and normal value
volume of air in one inspiration; 400-500 mL
Functional Residual Capacity definition and normal value
what’s left in the lungs following a normal expiration; 2600-3400 mL
Vital Capacity definition and normal value
amount of volume expired following a maximal inspiration; 3400-4500 mL
Residual Volume definition and normal value
amount of air left after a maximal expiration; 1500-1900 mL
Total Lung Capacity definition
amount of air inside the lungs at maximal inspiration;
Obstructive Lung Disease; definition, types, effects
increased resistance due to decreased caliber; decreased ERV, increased RV and increased TLC
COPD, asthma
Restrictive Lung Diseases; definition, types, effects
increased resistance to expansion; lowered TLC and abnormal lung tissue;
pulmonary fibrosis, silicosis, asbestosis and musculoskeletal resistrictions
measuring reserve volume
helium dilution technique
Minute Ventilation: formula and definition
amount of volume entering or leaving the mouth or nose per minute ~5-6 L/min
Alveolar Ventilation
a little less than the minute volume because of the amount of ventilation stuck in the anatomical dead space; ~4.5-5 L/min
Alveolar dead space
the amount of alveoli (in volume) that do not receive adequate blood supply to exchange oxygen and are therefore shut off
Physiological dead space
anatomical dead space and alveolar dead space summed together
symbols for arterial oxygen pressure and alveolar oxygen pressure
Arterial = paO2 Alveolar = pAO2
what is the best functional measure of the adequacy of ventilation?
pACO2 or paCO2; since it is supposed to be regulated at 40-45 mmHg
two possible causes of hypoventilation
minute ventilation (Ve or Vt) can be too low or dead space ventilation (Vd) can be too high; the latter can be brought on by stroke, drug overdose or severe lung disease
alveolar ventilation equation
alveolar ventilation (Va) = (CO2 production (VeCO2)/alveolar pressure CO2 (pACO2)) x K (0.863)
alveolar gas equation
pAO2 = pIO2 - (pACO2/RER)
alveolar O2 = O2 partial pressure in trachea - (alveolar CO2/respiratory exchange rate)
RER = 0.8
ways to decrease alveolar PO2
lower FiO2 like in a fire; lower barometric pressure like by climbing to a high elevation; and any change involving PCO2
AaO2 definition and clinical purpose
PAO2 - PaO2 = AaO2, which can be used to ID gas exchange problems in the clinic
