GAS EXCHANGE

Question 1

pulmonary ventilation

Answer 1

breathing
inspiration & expiration
VOLUME OF AIR BREATHED IN & OUT PER MINUTE

Question 2

alveolar ventilation

Answer 2

amount of gas reaching alveoli in one breath
VOLUME OF AIR EXVHANGED BETW ALVEOLI AND ATMOSPHERE PER MINUTE
(represents the new volume of air available for gas exchange with blood)

Question 3

deadspace ventilation

Answer 3

rest of gas taken in during the breath
remains in space
not capable of gas exchange

Question 4

trachea and conducting airway

Answer 4

not capable of gas exchange

Question 5

total deadspace

Answer 5

anatomic deadspace + alveolar deadspace

Question 6

anatomic dead space

Answer 6

ventilated
not perfused
made of conducting airways

Question 7

conducting airways

Answer 7

trachea
bronchi
bronchioles
they have NO ALVEOLI = no gas exchange = air remains in these regions during inspiration & expiration

Question 8

alveolar deadspace

Answer 8

volume of gas within unperfused alveoli

Question 9

ventilation

Answer 9

rate at which gas is passing through lungs

Question 10

perfusion

Answer 10

rate at which blood is passing through lungs

Question 11

pulmonary ventilation equation

Answer 11

pulmonary ventilation (L) = TV (L/breath) x RR (breath/ min)

Question 12

alveolar ventilation equation

Answer 12

alveolar ventilation = (TV - dead space volume) x RR

Question 13

is alveolar ventilation less or more than pulmonary ventilation?

Answer 13

alveolar ventilation is less than pulmonary due to the volume of air lost in anatomical dead space

Question 14

what do local controls work on to match air flow to blood flow?

Answer 14

smooth muscles of airway and arterioles

Question 15

increased perfusion in alveoli leads to

Answer 15

accumulation of CO2 in alveoli
results in a decrease in airway resistance
thus increased airflow

Question 16

increased ventilation

Answer 16

increase alveolar O2 concentration
increase pulmonary vasodilation
increases blood flow to match larger airflow

Question 17

where perfusion is greater than ventilation, an increase in CO2 causes ..

Answer 17

dilation of local airways

increase airflow

Question 18

where perfusion is greater than ventilation, a decrease in O2 causes ..

Answer 18

constriction of local blood vessels

blood flow decreases

Question 19

where ventilation is greater than perfusion, a decrease in CO2 leads to ..

Answer 19

constriction of local airways

decrease airflow

Question 20

where ventilation is greater than perfusion, an increase in O2 leads to ..

Answer 20

dilation of local blood vessels

increased blood flow

Question 21

4 factors that effect the rate of gas exchange across alveolar membrane

Answer 21

1. partial pressure gradient of O2 & CO2
2. diffusion coefficient of O2 & CO2
3. S.A. of alveolar membrane
4. Thickness of alveolar membrane

Question 22

PAO2 equation

Answer 22

PAO2 = PiO2 - [PaCO2/ 0.8]
0.8 is the RER
A = alveolar air
a = arterial blood

i = inspired air

Question 23

PiO2 equation

Answer 23

PiO2 = Patm - Pwv

Question 24

diffusion coefficient meaning

Answer 24

solubility of gas in membrane
CO2 solubility is greater than O2
so diffusion coefficient for CO2 is 20 x that of O2

Question 25

what does pulmonary circulation receive

Answer 25

the whole of the cardiac output

Question 26

Frick’s law of diffusion

Answer 26

amount of gas that moves across a sheet of tissue in unit time
proportional to area of sheet
inversely proportional to its thickness

Question 27

conducting zone

Answer 27

bronchi
bronchioles
terminal bronchioles

Question 28

transitional and respiratory zones

Answer 28

respiratory bronchioles
alveolar ducts
alveolar sacs