gas transport

Question 1

what does the O2 cascade describe (relate to Fick’s law)

Answer 1

increasing oxygen tension from inspired air to respired cells; Fick’s law states that flow rate is proportional to pressure gradient

Question 2

effect of structural disease, fluid in alveolar sacs and hypoxic gas on oxygen tension (PaO2)

Answer 2

structural disease reduces area, fluid in alveolar sac increases thickness and diffusion distance, hypoxic gas reduces gradient

Question 3

values of PaO2 in air, alveoli, tissues and veins (kPa)

Answer 3

air: 21.3, alveoli: 13.5, tissues: 13.3, veins: 5.3

Question 4

shape of oxygen dissociation curve

Answer 4

sigmoidal

Question 5

shape of CO2 dissociation

Answer 5

linear

Question 6

graph of PaO2 and location

Answer 6

benjis

Question 7

3 challenges to oxygen cascade based on alveolar ventilation

Answer 7

V/Q matching, diffusion capacity, cardiac output

Question 8

explain how V/Q matching is a challenge to oxygen cascade

Answer 8

if blockage in respiratory tree, and not ventilating but perfusing, then will not gain oxygen and will drop

Question 9

explain how diffusion capacity is a challenge to oxygen cascade

Answer 9

thickness of exchange surface will reduce oxygen gain

Question 10

explain how cardiac output is a challenge to oxygen cascade

Answer 10

need high cardiac output to move blood to tissues

Question 11

describe altitude oxygen cascade

Answer 11

reduced ambient pressure reduces oxygen and gradient, so is harder to maintain homeostasis

Question 12

graph of PaO2 and location at altitude

Answer 12

benjis