Exchange of air gases

Question 1

What are the major gases?

Answer 1

Nitrogen, oxygen, carbon dioxide, water

Question 2

Minor gases

Answer 2

argon, neon, helium, methane

Question 3

Atmospheric pressure

Answer 3

sum of all gas contributions

Question 4

Dalton’s Law

Answer 4

total pressure of a gas mixture is equal to the sum of the partial pressures of its individual gases

Question 5

Alveolar air is altered by

Answer 5

contact with mucus membranes, water pressure incr
mixing with residual air leftover from previous respiratory cycle, carbon dioxide pressure incr, oxygen pressure decr
rapid exchange of O2 and CO2 with blood

Question 6

For oxygen to reach the blood what must it do?

Answer 6

dissolve in the aqueous layer
cross the respiratory membrane

Question 7

Alveolar gas exchange

Answer 7

transport of oxygen and carbon dioxide across the respiratory membrane

Question 8

What dictates the direction of flow?

Answer 8

pressure gradient of each gas in the air and fluid

Question 9

Does one gas influence diffusion of another in the alveolus?

Answer 9

no

Question 10

How long does it take for alveolar gas exchange to reach equilibrium?

Answer 10

0.25 seconds

Question 11

What factors affect the efficiency of alveolar gas exchange?

Answer 11

pressure gradient of gases
solubility of gases
thickness of respiratory membrane
area of respiratory membrane
ventilation-perfusion coupling

Question 12

If ventilation is good and oxygen is present, what increases?

Answer 12

perfusion

Question 13

Blood flow matches

Answer 13

airflow in the lungs

Question 14

In systemic tissues if there is poor oxygen do you get vasodilation or vasoconstriction?

Answer 14

vasodilation

Question 15

In lung tissues if there is poor oxygen, do you get vasodilation or vasoconstriction?

Answer 15

vasoconstriction

Question 16

oxyhemoglobin

Answer 16

hemoglobin with one or more oxygen bound to it

Question 17

deoxyhemoglobin

Answer 17

hemoglobin without oxygen

Question 18

One hemoglobin molecule can carry how many oxygen molecules ?

Answer 18

four

Question 19

Each heme has how many iron atoms ?

Answer 19

1

Question 20

Cooperative binding

Answer 20

when one molecule of oxygen binds others hop on more easily

Question 21

Carbon monoxide binds 210x more tightly to hemoglobin than oxygen which could lead to ?

Answer 21

poisoning or suffocation

Question 22

How is carbon dioxide transported?

Answer 22

most is hydrated to form carbonic acid
binds to amino groups of plasma proteins and hemoglobin
could also be carried away in blood

Question 23

Haldane effect

Answer 23

binding of oxygen to hemoglobin promotes the release of carbon dioxide from hemoglobin

Question 24

Bohr effect

Answer 24

the affinity of hemoglobin for oxygen is proportional to pH

Question 25

In systemic gas exchange where does carbon dioxide go? What about oxygen?

Answer 25

carbon dioxide goes into the capillary blood oxygen goes into the repairing tissue

Question 26

In alveolar gas exchange where does the carbon dioxide go? What about oxygen?

Answer 26

carbon dioxide goes into the alveolar air oxygen goes into the capillary blood

Question 27

What is oxygen unloading influenced by ?

Answer 27

Low oxygen/ambient oxygen pressure high temperature high acidity Bisphosphoglycerate

Question 28

Bisphosphoglycerate is influenced by which 5 stimuli?

Answer 28

thyroxine testosterone fever growth hormone adrenaline/epinephrine

Question 29

What is normal blood pH ?

Answer 29

7.35-7.45

Question 30

What is normal carbon dioxide pressure in the blood?

Answer 30

40 mmHg

Question 31

What is normal oxygen pressure in the blood?

Answer 31

95 mmHg

Question 32

What monitors the composition of blood and CSF?

Answer 32

central and peripheral chemoreceptors

Question 33

What is the most potent stimulus for breathing?

Answer 33

pH

Question 34

Acidosis

Answer 34

high CO2 blow off CO2 by increasing ventilation

Question 35

Alkalosis

Answer 35

Low CO2 retain CO2 by reducing ventilation

Question 36

Hyperventilation

Answer 36

response to acidosis pushes reaction to the left: CO2 + H2O <- H2CO3 <- HCO3^- + H^+

Question 37

Hypoventilation

Answer 37

response to alkalosis shifts reaction to the right which decreases pH

Question 38

How does carbon dioxide in the blood influence respiratory rate?

Answer 38

brain responds to increased CO2 at the start of exercising CO2 can cross blood brain barrier to react with water in CSF to make hydrogen ions

Question 39

How does oxygen in the blood influence respiratory rate?

Answer 39

not as much effect on respiration as H ions or carbon dioxide if hypoxemia can significantly stimulate ventilation