Pulmonary Ventilation

Question 1

Avg. Alveolar Diameter

Answer 1

100 um

Question 2

Normal Lung Compliance

Answer 2

200 mls of air/ 1 cm H20 increase in transpulmonary pressure

Question 3

What does an increase in transpulmonary pressure indicate?

Answer 3

Forces trying to collapse the lung have increased

Question 4

How much air is drawn in with each breath?

Answer 4

500 mls

Question 5

Normal Alveolar Pressures

Answer 5

0 cmH20 (ATM pressure) at rest
-1 cmH20 upon inspiration
+1 upon expiration

Question 6

Normal Pleural Pressures

Answer 6

• 5 cmH20 at rest

- 7.5 cmH20 upon inspiration

Question 7

How long does it take to inspire and expire air?

Answer 7

2 seconds inspire

2-3 seconds expire

Question 8

Compliance

Answer 8

How much the lungs will expand with each unit increase in transpulmonary pressure

Question 9

What is constant in the compliance curve?

Answer 9

Alveolar pressure

Question 10

What changes in compliance curve?

Answer 10

Pleural pressure and change in volume of air that moves

Question 11

What determines the shape of the compliance curve?

Answer 11

Elastic forces of the lungs (Not linear because lung is trying to collapse, taking more force to overcome resistance creating the “lag”)

Question 12

Elastic forces of lung tissue

Answer 12

Elastin & collagen (stretch as lungs fill)

1/3 total elastic forces

Question 13

Elastic forces caused by surface tension in alveoli wall

Answer 13

2/3 total elastic forces

Needs surfactant

Question 14

Air-water interface

Answer 14

water molecules at the surface form very strong attraction cause the water surface to contract

Question 15

Surfactant

Answer 15

Reduces surface tension of water
Secreted by Type II alveolar epithelial cells
10% alveolar surface area
Contains phospholipids (reduce surface tension 8-50%)

Question 16

What effects does CPB have on surfactant?

Answer 16

Minimal

Question 17

Alveolar Pressure Created as elastic factors work to collapse them

Answer 17

4 cm H20

Question 18

Collapsing Pressure Equation

Answer 18

Collapsing Pressure= (2xSurface Tension)/(Radius alveolus)

Question 19

Alveolar Pressure generated without surfactant

Answer 19

18 cm H20

Question 20

When does surfactant in babies start to form?

Answer 20

During 6th and 7th month of gestation

Question 21

Alveolus diameter in premature babies

Answer 21

less than 1/4 that of adult

Question 22

Respiratory Distress Syndrome of the Newborn

Answer 22

Alveolus tend to collapse in babies 6-8 times that of a normal adult

Question 23

Compliance of “Everything” (Lungs & thorax)

Answer 23

110 mls/cm H20 (1/2 that of lungs alone)

Question 24

Compliance or Elastic Work

Answer 24

Force required to expand lungs against all elastic forces

Question 25

Tissue Resistance Work

Answer 25

Force required to expand lungs against viscosity of tissue

Question 26

Airway resistance Work

Answer 26

Forces required to overcome airway resistance to air flow

Question 27

Percent of energy use by body for normal pulmonary ventilation

Answer 27

3-5%

increases 50x during heavy exercise

Question 28

Inspiratory Capacity Volume

Answer 28

3500 mls

Question 29

Functional Residual Capacity

Answer 29

2300 mls; Air that remains in lungs after normal expiration

Question 30

Vital Capacity

Answer 30

4600 mls; Amt of air that we can access

Question 31

Total Lung Capcity

Answer 31

5800 mls; Max volume lungs can hold

Question 32

R

Answer 32

respiratory exchange ratio

Question 33

CaO2

Answer 33

concentration of oxygen in arterial blood

Question 34

CvO2 (line over v)

Answer 34

concentration of oxygen in mixed venous blood

Question 35

SO2

Answer 35

percentage saturation of hemoglobin with oxygen

Question 36

SaO2

Answer 36

percentage saturation of hemoglobin with oxygen in arterial blood

Question 37

Minute Respiratory Volume

Answer 37

(Tidal Volume) x (Respiratory Rate)

Question 38

Alveolar Ventilation

Answer 38

(Tidal Volume-Dead space) x (Respiratory Rate)