Lecture 3 Resp (Principles of gas exchange)

Question 1

co2 and o2 are exchanged by what transport

Answer 1

simple diffusion

Question 2

c02 and 02 diffusion are driven by what energy of each individual molecule

Answer 2

kinetic energy

Question 3

what is the most important parameter in gas exchange

Answer 3

the rate of diffusion

Question 4

total pressure of a chamber of gasses is directly proportional to what?

Answer 4

The concentration of all molecules

Question 5

Pressure exerted by all molecules of the certain type is called the…

Answer 5

Partial pressure

Question 6

what is the composition of o2 in the atmosphere

Answer 6

21% (160mmhg)

Question 7

what is the composition of nitrogen in the atmosphere

Answer 7

79% (500mmhg)

Question 8

carbon dioxide dissolves rapidly or slowly?

Answer 8

rapidly

Question 9

when co2 and h20 combine to form carboxylic acid slowly through carbonic anhydrase, do they still contribute to partial pressures

Answer 9

no

Question 10

what is henry’s law

Answer 10

pressure = concentration/solubility (a gas in liquid phase)

Question 11

diffusion rate “D” is driven by the differences in what?

Answer 11

partial pressure differences

Question 12

higher solubility increases or decreases diffusion rate

Answer 12

increases (they travel in fluid form)

Question 13

increase cross sectional area increases or decreases diffusion rate

Answer 13

increases

Question 14

decreased distance gases must travel increase or decrease diffusion rate

Answer 14

increase

Question 15

increases molecular weight increases or decreases diffusion rate

Answer 15

decreases

Question 16

because o2 diffusion coefficient is 1, and co2 is 20.3, this means that co2 does what

Answer 16

diffuses faster and better

Question 17

what is the main dissolving media for gasses in live tissues

Answer 17

water

Question 18

Are pulmonary capillaries endothelial lined or epithelial?

Answer 18

Endothelial

Question 19

Are alveoli capillaries endo or epithelial lined?

Answer 19

Epithelial

Question 20

Can transpulmonary gasses go from both high to low, and LOW to HIGH concentration?

Answer 20

yes (but net filtration is always from high to low)

Question 21

The pressure that water molecules exert upon escaping is called?

Answer 21

Vapor pressure

Question 22

What is normally thte phase of water at body temperature?

Answer 22

Gas phase (insensible loss because water wants to vaporize, and can do so in the alveoli)

Question 23

In a single respiration, what is the MOST transported molecule across the pulmonary membrane?

1. o2
2. Co2
3. Water

Answer 23

3. Water (a difference of 47%)
   (02 is 7%, co2 is 40%)
   see slide 10.

Question 24

What percentage of tidal volume versus total lung volume during quiet respiration is actually participating in gas exchange?

Answer 24

15%

lung volume: 2300ml, tidal average 350ml

Question 25

What is the reason alveolar air upon inspiration contains 40mmg of co2, then upon exhale it is only 27mmhg?

Answer 25

Because the air in the dead space reflects atmospheric air, which when mixed during expiration, changes the average value of all those gasses to resemble something closer to atmospheric condition.

Question 26

what alveolar substance does not change in concentration (partial pressure) when mixed with dead space?

Answer 26

Water

Question 27

what is the mechanism by which we attempt to compensate for the bodies increased demand in oxygen?

Answer 27

Breathing

Question 28

What decreases partial pressure of alveoli?

Answer 28

increased absorption (metabolic demand)

Question 29

What increases the partial pressure of 02 in alveoli?

Answer 29

Increased breathing

Question 30

What are the 4 structures of the “Respiratory Unit”

Answer 30

Respiratory Bronchiole
Alveolar Ducts
Atria
Alveoli

Question 31

What layer of the respiratory membrane is thickened during pulmonary edema?

Answer 31

The interstitial layer

Question 32

What is the pressure in the interstitium between the respiratory membranes?

Answer 32

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