Lecture 17: Gas Exchange: O2

Question 1

Dalton’s law

Answer 1

gas’s pressure is proportional to its conc

Question 2

partial pressure

Answer 2

pressure exerted by each gas of total gas pressure

partial because of indiv gas when there is more than one

Question 3

atmopsheric pressure at 2389 ft

Answer 3

700 mmHg

Question 4

Pps of deoxyg blood

Answer 4

PO2 40 mmHg

PCO2: 45 mmHg

Question 5

Pps of oxyg blood

Answer 5

PO2: 100 mmHg
PCO2: 40 mmHg

Question 6

How much fresh air enters with inspiration?

Answer 6

about 55mL
mixes w/ FRC (2400 mL)
very little compared to whas already there (FRC)

Question 7

When fresh air enters, [O2]…

Answer 7

inc slightly

Question 8

When fresh air enters, [CO2]…

Answer 8

dec slighltly

Question 9

When fresh air enters, average alveolar value

Answer 9

DOES NOT CHANGE much

constant situation means we have predictable rate of exchange

Question 10

expired air comparied to inspired air conc

Answer 10

lower [O2]

higher [CO2]

Question 11

why lower [CO2] inspired than expired

Answer 11

b/c O2 removed from lungs by blood during inspiration

Question 12

CO2 movement during breath

Answer 12

moves from blood to lungs and is exhaled

Question 13

gases in lungs (tissue and lung levels)

Answer 13

constantly taking O2 out and putting CO2 in

Question 14

O2 at tissues

Answer 14

leaves capps and goes into cells

Question 15

CO2 at tissues

Answer 15

enters caps

Question 16

venous blood concs

Answer 16

high CO2
low O2 (comes into caps at 100, leavs at 40)

Question 17

Fick method

Answer 17

O2 consumption= blood flow x (tissue oxygen extraction)
aka C.O. x ([arterial O2] - [mixed venous O2])
most direct and accurate way to measure whole body O2 uptake

Question 18

O2 consumption

Answer 18

measured using Fick method

depends on level of activity

Question 19

see slide 10

Answer 19

10

Question 20

Fick relationship

Answer 20

CO2 production measured

values go up (down in O2 one)

Question 21

Fick relationship equation

Answer 21

CO2 production= blood flow x (tissue CO2 production)

aka C.O. X ([CO2 mixed venous] - [co2 arterial])

Question 22

O2 concs at rest vs. max

Answer 22

rest: 250
max: 3500
more than 10 fold increase

Question 23

CO2 concs at rest vs max

Answer 23

rest: 200
max: 3800
close to 20 fold increase

Question 24

amounts of O2 consumed and CO2 produced are

Answer 24

NOT EQUAL

Question 25

respiratory quotient (RQ) equation

Answer 25

amount CO2 made/O2 consumed

Question 26

RQ varies with

Answer 26

nutrient type

Question 27

pure fat RQ

Answer 27

0.7

7 mL pure CO2 produced for every 10 mL pure O2 used

Question 28

pure carb RQ

Answer 28

1.0

CO2 produced and O2 consumed are about equal

Question 29

partial pressuure O2 in atmosphere

Answer 29

21

Question 30

partial pressure N2 in atomsphere

Answer 30

79

Question 31

atomospheric PO2 vs. alveolar PO2

Answer 31

atmosphere: 159
alveoli: 105

Question 32

atomospheric PCO2 vs. alveolar PCO2

Answer 32

atmosphere: 0.3
alveoli: 40

Question 33

why oxygen PP doesn’t match between alveolar and oxy blood

Answer 33

nutritient exchange in lung to feed lungs

Question 34

best place to look for mixed venous blood

Answer 34

right ventricle, right atrium, pulmonary artery

Question 35

with oxygen we make

Answer 35

water

Question 36

we get CO2 from

Answer 36

the fuel we use