Phys 3 Gas exchange

Question 1

What does the bronchiole diameter control?

Answer 1

Question 2

What controls the airway resistance?

Answer 2

This happens by the smooth muscle in airway walls

Question 3

Why do we want to change airway resistance?

Answer 3

Question 4

Point of the lungs is to bring what together?

Answer 4

Question 5

What is Alveolar ventilation?

Perfusion?

Answer 5

Question 6

J

What is it?

Answer 6

how much gas is exchanged every minute is equal to asking what is J

Question 7

under normal conditions what is J?

Answer 7

Question 8

CO2 vs O2 gas exchange

are they coupled?

Answer 8

Question 9

what factors in the J equation are dependent on the structure of the alveolus?

Answer 9

Question 10

S.A.

correspods to what?

Answer 10

• Lots of alveoli (millions)
• If a single layer= 70 sq. meters
• Also depends on number of “open” pulmonary capillaries
  
  • varies with demand
  • at rest approx 70 mL of blood in pulmonary capillaries
  • exercise= as much as 200 mL

Question 11

Altering S.A.

what disease can cause this?

Answer 11

If S.A. increases then J increases

Question 12

Distance

what distance?

what creates this distance?

whats avg?

Answer 12

Diffusion distance (thickness of alveolar barrier)

Question 13

Altering distance

what can alter it?

what does this cause?

what can cause the alteration?

Answer 13

• As distance increases, J decreases
• Lung of a patient with INTERSTITIAL LUNG DISEASE
  
  • deposition of collagen has increased the distance for diffusion

Question 14

D

what is it?

what does it depend on?

Answer 14

Question 15

D of CO2 vs O2

Answer 15

O2 is less soluble than CO2 in water

Question 16

Describe how the resistance of the airways is controlled and the consequences of changes in airway resistance?

Answer 16

Question 17

(P₁-P2)

Answer 17

consider each gas seperately

For CO2 it would be

40-45= -5 mm Hg

P_{ACO2= 40}

P_VCO2= 45

so it would go out of RBC to the alveolar space

Question 18

How long does it take to reach equillibrium (O2)

Normal conditions?

Answer 18

blood stays in for .75 seconds

Question 19

In exercise equillibrium (O2)

Answer 19

Question 20

Diffusion capacity of the lung for oxygen?

Answer 20

Question 21

DL02

How do we measure it?

Answer 21

Question 22

D_LCO2

Answer 22

Question 23

surface tension is between what?

Answer 23

Question 24

how to measure pressure of round sac?

Answer 24

Question 25

if there are changes in LaPlaces law (such as radius)

what happens

Answer 25

A pressure gradient is formed. air will go down gradient making small alveoli smaller and big alveoli bigger this will cause a cascade of smaller alveoli draining air to the bigger alveoli.

Question 26

What prevents alveoli from having different pressures?

Answer 26

surfactant decreases T in proportion to the radius

which reduces pressure in the small alveoli

Question 27

Surfactant produced by?

composed of?

stored?

Answer 27