Lec 26

Question 1

air is composition of

Answer 1

78% N2
21% O2
0.033% CO2

Question 2

Dalton LAw

Answer 2

total pressure exerted by mixture is sum of pressures exerted by all individuals gases

Question 3

pressure exerted by individual gas

Answer 3

partial pressure

Question 4

P gas in dry air

Answer 4

p atm * %gas in atmosphere

Question 5

p gas in humid air

Answer 5

(p atm- p H2O) * %gas in atmosphere

Question 6

P(CO2) and P(O2) in atmosphere

Answer 6

PO2=160 mmhg
PCO2= 0.25 mmhg

Question 7

alveolar partial pressure

Answer 7

PO2= 100mmhg
PCO2= 40mmhg
because of still air

Question 8

ventilation can vary to match —- with —-

Answer 8

perfusion with ventilation

Question 9

O2 and CO2 should pass from what barriers in body

Answer 9

epithelial cells and capillary endothelial cells

Question 10

diffusion if gas is governed by – law

Answer 10

fick

Question 11

rate of diffusion directlly proportional to

Answer 11

1- surface area (A)
2- membrane permeability (D)
3- partial pressure gradient

Question 12

rate of diffusion inversely proportional to

Answer 12

1- diffusion distance (T)
membrane thickness
interstitial fluid

Question 13

diffusion rate

Answer 13

ADdP/T^2

Question 14

atmosphere and alveoli pressure gradient

Answer 14

O2 will diffuse inside alveoli (160>100)
CO2 will diffuse outside of alveoli to atmosphere(40>0.25)

Question 15

pulmonary circulation is btw

Answer 15

alveoli and capillary

Question 16

systemic circulation is btw

Answer 16

arterial and tissue

Question 17

P(O2) and P(CO2) arterial blood

Answer 17

100 mmHg
40 MMHg
large partial pressure gradient

Question 18

P(O2) and P(CO2) venous blood

Answer 18

<40 mmHg
>46 mmHg

Question 19

Diffusion reaches —- under normal circumstances

Answer 19

Equilibrium

Question 20

what it mens by diffusion equilibrium

Answer 20

Maximally offload CO2
Maximally upload O2

Question 21

Hypoxia

Answer 21

not enough O2

Question 22

Alveolar gas exchange is influenced by

Answer 22

1- adequate perfusion of alveoli
2- gas diffusion btw alveoli and blood
3- O2 reaching alveoli

Question 23

Factors that decrease O2 reaching the alveoli

Answer 23

1- low O2 content in atm
2- low alveolar ventilation

Question 24

low alveolar ventilation is caused by

Answer 24

1- decreased lung compliance
2- increased airway resistance
3- CNS depression(drug,alcohol)

Question 25

pathological conditions leads to hypoxia

Answer 25

1- emphysema 2- asthma 3- fibrotic lung disease 4- pulmonary edema

Question 26

Emphysema

Answer 26

destruction of alveoli -- less SA for gas exchange **Low SA , PO2 low or normal**

Question 27

asthma

Answer 27

1-bronchioles constricted 2-increase airway resistance 3-decrease alveolar ventilation **Low PO2**

Question 28

fibrotic lung disease

Answer 28

1- build up scar tissue around alveoli 2- thickened alveolar membrane 3- slow gas exchange 4- decrease alveolar ventilation **higher distance, normal or low PO2**

Question 29

pulmonary edema

Answer 29

fluid in interstitial space increases (heart failure) arterial PCO2 may be normal as soluble in water **higher distance**