Oxygen and carbon dioxide week 4

Question 1

In what ways are alveolar atmospheric air different from normal atmospheric air?

Answer 1

the alveolar are has more CO2 and water, thus it is more dilute.

Question 2

Which is more soluble in water (blood), CO2 or O2?

Answer 2

CO2 is highly soluble and oxygen is much less

Question 3

The rate of diffusion in the net direction is affected by what 5 things?

Answer 3

1. solubility of the gas in liquid
2. Surface area of the barrier across which diffusion occur
3. Distance of diffusion(membrane thickness)
4. Molecular weight of gas
5. Temperature ( not really an issue due to constant body temp

Question 4

Why is aqueous diffusion the limiting factor?

Answer 4

because respiratory gases are highly soluble in lipids (cells/tissues)

Question 5

rate of diffusion =

Answer 5

change in pressure x surface area x solubility constant / distance of diffusion x MW

Question 6

what is tidal volume?

Answer 6

the actual amount of air displace between inhalation and exhalation. roughly 350 mL while 2300mL stays in lungs

Question 7

What does the functional residual capacity do?

Answer 7

acts as a buffer that prevents sudden changes in the alveolar gas mix, which is useful for keeping blood gas levels fairly constant

Question 8

What 2 things control the amount of oxygen in the alveoli at a given time?

Answer 8

1. ventilation from breathing

2. rate of absorption from the blood

Question 9

Describe the ventilation/perfusion ratio?

Answer 9

the relationship between alveolar ventilation and alveolar perfusion.
VA= ventilation of a given alveolus
Q= the blood flow to that alveolus
expressed as a function of pp of O2 and CO2

Question 10

what happens when VA/Q=0

Answer 10

no air is reaching the alveolus, thus Q=0. The partial pressures will equilibrate with that of the pulmonary blood

Question 11

what happens when VA/Q=normal

Answer 11

you have normal blood flow and ventilation to the alveolus.

Question 12

What happens when VA/Q = infinity

Answer 12

you have poor blood flow to the alveolus thus no profusion and no gas exchange occurs. thus the partial pressure of O2 is equal to humidified air, while no CO2 is exchanged.

Question 13

What is the physiological shunt?

Answer 13

when you can’t get enough O2 to blood, the blood will pass by without be oxygenated and is called shunted blood. This occurs as VA/Q approaches 0.

Question 14

When does physiological dead space air increase?

Answer 14

as supplied ventilation is greater than perfusion, thus you have left over oxygen to do nothing with

Question 15

In a normal standing person where is there physiological dead space and where is there shunted blood in relation to the lungs?

Answer 15

• at top of the lung there will be more physiological dead space due to the natural decreased blood flow
• at the bottom of the lung there will be increased shunted blood due to a higher amount of blood flow, resulting in more deoxygenated blood passing out of the lung.

Question 16

Transport of blood gases depends on what 2 things?

Answer 16

rate diffusion and movement of blood(how much passes a given point per time)

Question 17

what are the partial pressures of O2 in the alveoli, arteries, tissue capillaries, and venous return?

Answer 17

alveoli=105 mm Hg
artery= 95 mm Hg
tissue capillary= 95 dropping to 40
venous return= 40 mmHg

Question 18

high partial pressures of O2 _____ binding to hemoglobin, and low pressures ______disassociation of O2 from hemoglobin?

Answer 18

increase

favor

Question 19

T/F oxygen binds to hemoglobin as a diatomic molecule?

Answer 19

True, at each binding site you get two oxygens

Question 20

What does cooperative binding mean?

Answer 20

for each site on hemoglobin (hb) occupied by O2, the affinity of the following site for O2 is increased. Thus more O2= more affinity for hb binding.

Question 21

Hemoglobin release of O2 increases or decreases as partial pressure of O2 decreases

Answer 21

increases, and leads to more oxygen release from hemoglobin. Thus the reverse of cooperative binding

Question 22

what is the utilization coefficient?

Answer 22

the percentage of blood that gives up its O2.

around 25% at rest and exercise increases this to about 85%

Question 23

A shift to the right on the O2 disassociation curve means what?

Answer 23

there is a decreased affinity for O2 on hb, thus hb wants to get rid of O2

Question 24

what 4 things can causes a shift to the right?

Answer 24

increased temp, partial pressure of CO2, 2,3-DPG and a decrease of pH. basically think about exercise and what happens to the body when you exercise.

Question 25

What is a a hemoglobin called that binds to CO2? and how many molecules can bind to a heme group?

Answer 25

carbaminohemoglobin

4 CO2/ heme just like O2

Question 26

Which has to most affinity to hemoglobin: CO, O2, or CO2?

Answer 26

CO thus carbon monoxide poisoning is dangerous and persons need to be subject to a saturation of oxygen

Question 27

What is the Haldane effect?

Answer 27

states that deoxygenated blood has an increased ability to carry carbon dioxide, and oxygenated blood carries less CO2

Question 28

What is the Bohr effect?

Answer 28

relates to how pH and CO2 affect the blood capacity for carrying O2.