Respiration Lecture 8

Question 1

Two zones of the lungs anatomically

Answer 1

Conducting zone: trachea to 16th split
anatomical dead space

Respiratory zone: 17th split to alveolae
terminal respiratory unit found here

Question 2

Tidal Volume: definition and normal value

Answer 2

volume of air in one inspiration; 400-500 mL

Question 3

Functional Residual Capacity definition and normal value

Answer 3

what’s left in the lungs following a normal expiration; 2600-3400 mL

Question 4

Vital Capacity definition and normal value

Answer 4

amount of volume expired following a maximal inspiration; 3400-4500 mL

Question 5

Residual Volume definition and normal value

Answer 5

amount of air left after a maximal expiration; 1500-1900 mL

Question 6

Total Lung Capacity definition

Answer 6

amount of air inside the lungs at maximal inspiration;

Question 7

Obstructive Lung Disease; definition, types, effects

Answer 7

increased resistance due to decreased caliber; decreased ERV, increased RV and increased TLC
COPD, asthma

Question 8

Restrictive Lung Diseases; definition, types, effects

Answer 8

increased resistance to expansion; lowered TLC and abnormal lung tissue;
pulmonary fibrosis, silicosis, asbestosis and musculoskeletal resistrictions

Question 9

measuring reserve volume

Answer 9

helium dilution technique

Question 10

Minute Ventilation: formula and definition

Answer 10

amount of volume entering or leaving the mouth or nose per minute ~5-6 L/min

Question 11

Alveolar Ventilation

Answer 11

a little less than the minute volume because of the amount of ventilation stuck in the anatomical dead space; ~4.5-5 L/min

Question 12

Alveolar dead space

Answer 12

the amount of alveoli (in volume) that do not receive adequate blood supply to exchange oxygen and are therefore shut off

Question 13

Physiological dead space

Answer 13

anatomical dead space and alveolar dead space summed together

Question 14

symbols for arterial oxygen pressure and alveolar oxygen pressure

Answer 14

Arterial = paO2
Alveolar = pAO2

Question 15

what is the best functional measure of the adequacy of ventilation?

Answer 15

pACO2 or paCO2; since it is supposed to be regulated at 40-45 mmHg

Question 16

two possible causes of hypoventilation

Answer 16

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

Question 17

alveolar ventilation equation

Answer 17

alveolar ventilation (Va) = (CO2 production (VeCO2)/alveolar pressure CO2 (pACO2)) x K (0.863)

Question 18

alveolar gas equation

Answer 18

pAO2 = pIO2 - (pACO2/RER)
alveolar O2 = O2 partial pressure in trachea - (alveolar CO2/respiratory exchange rate)
RER = 0.8

Question 19

ways to decrease alveolar PO2

Answer 19

lower FiO2 like in a fire; lower barometric pressure like by climbing to a high elevation; and any change involving PCO2

Question 20

AaO2 definition and clinical purpose

Answer 20

PAO2 - PaO2 = AaO2, which can be used to ID gas exchange problems in the clinic