Gas Exchange

Question 1

What does surfactant do?

Answer 1

Reduces the surface tension by reducing the attraction of water molecules for one another

Question 2

What are the 4 surfactant proteins?

Answer 2

SP-A, SP-B, SP-C, SP-D

Question 3

What is surfactant made up of?

Answer 3

A phospholipid named dipalmitoyl phosphatidylcholine (DPPC) and 4 surfactant proteins

Question 4

What is the function of SP-A?

Answer 4

regulate DPPC secretion and function

Question 5

What is the function of SP-B?

Answer 5

adjusting surface tension (surface tension reduction)

Question 6

What is the function of SP-C?

Answer 6

adjusting surface tension, similar to SP-B (surface tension reduction)

Question 7

What is the function of SP-D?

Answer 7

regulate DPPC secretion and function, similar to SP-A

Question 8

What is the function of prostaglandins in regards to surfactant?

Answer 8

Promote secretion of the surfactant by Type 2 pneumocytes

Question 9

What things inhibit secretion of surfactant?

Answer 9

SP-A and DPPC by negative feedback

Question 10

Changing what factor has the greatest effect on airflow?

Answer 10

Radius

Question 11

How much O2 crosses the alveolar border every minute?

Answer 11

250 mL

Question 12

How much CO2 crosses the alveolar border every minute?

Answer 12

200 mL

Question 13

What does J stand for?

Answer 13

Diffusion rate in ml / min

Question 14

What two factors in the J equation depend directly on the structure of the alveolus? What does this mean?

Answer 14

surface area and distance. They can be changed by pathology

Question 15

What condition lowers surface area of the alveoli?

Answer 15

COPD

Question 16

What 4 things make up the distance between the blood and an alveoli? What is the distance?

Answer 16

1.) Fluid layer 2.) Alveolar epithelium 3.) Interstitial space 4.) Blood vessel wall .6 microns

Question 17

How long does an RBC spend in a capillary under normal conditions? How long does it require to reach equilibrium?

Answer 17

3/4 of a second. 1/4 of a second.

Question 18

During exercise, how long may an RBC spend in a capillary? How may this affect someone with lung disease?

Answer 18

.25 seconds, meaning no extra buffer period. People with lung disease will notice this during exercise.

Question 19

What is the abbreviation for diffusion capacity of the lung for oxygen?

Answer 19

DLo2

Question 20

What is the DLo2 at rest?

Answer 20

21 ml O2/min/mm Hg

Question 21

How do you measure DLo2?

Answer 21

Carbon monoxide. Have patient inhale small amount of CO. Then multiple DLco x 1.23

Question 22

How long does it take for CO2 to reach equilibrium in the capillaries?

Answer 22

Not very long, almost instantaneously

Question 23

What is the DLco2?

Answer 23

400 ml CO2/min/mm Hg. This is the 20x the DLo2.

Question 24

Summary Slide

Answer 24

Question 25

What is interstitial lung disease? What effect does it have on J?

Answer 25

It is the depostition of collagen within interstitial spaces, this increases the diffusion distance and decreases diffusion.

Question 26

What does D depend on? (2 things)

Answer 26

The solubility of gas in water. The molecular weight of the gas