Lecture 9

Question 2

• What are the 3 areas where CO2 can be contained in the blood?
• what % of total CO2 is located in each area

Answer 2

1. 30% Carbaminohemoglobin
2. 60% of CO2 Transport by HCO3-
3. 10% of CO2 dissolved in plasma

Question 3

as pressure goes up will the amount of CO2 being dissolved go up or down?

Answer 3

up

Question 4

How is carbon dioxide exchanged in the systemic capillaries (internal respiration)

Answer 4

1. CO2 will enter the RBC and will bind with H20,
2. carbonic anhydrase will break it down to carbonic acid and bicarbonate, and H+ (carbonic anhydrase pathway)
3. bicarbonate exits the RBC (liberate bicarbonate) and will help keep pH in normal range 7.35-7.45

Question 5

How is carbon dioxide exchanged at the pulmonary capillaries (external respiration)

Answer 5

1. Once Bicarbonate gets to pulmonary capillary it will enter the RBC and go through the reverse carbonic anhydrase pathway
2. so that we can break down carbonic acid and release water, CO2,
3. CO2 will diffuse through pulmonary capillary wall and then it will be exhaled

Question 6

what Buffers acidity of carbon dioxide

Answer 6

bicarbonate

Question 7

What is the carbon dioxide content (ml/dl) of blood?

Answer 7

• Arteries- 48ml/dl
• Veins- 52ml/dl

Question 8

Describe the Haldane effect on carbon dioxide carriage by the blood.

Answer 8

The higher the PO2, more CO2 will be liberated and less CO2 content in the blood

Question 9

Explain the difference in diffusion rate between oxygen and carbon dioxide.

Answer 9

• CO2 is more soluble
• CO2 being carried in the blood than O2 even though the partial pressures are much higher in the arteries for O2.

Question 10

Write the alveolar ventilation equation and be able to apply it to different situations of CO2 production and alveolar ventilation

Question 11

Write the alveolar air equation and be able to solve it in different situations of barometric pressure, saturated water vapor pressure, fractional concentration of oxygen, and arterial partial pressure of carbon dioxide

Question 12

what is hypoxemia

Answer 12

Hypoxemia- Less than normal arterial oxygen partial pressure PaO2

PaO2= partial pressure of oxygen in arteriole blood

Question 13

1. what is the usual range of PaO2?
2. what does it depend upon?

Answer 13

1. Usual range is 80 – 100 mmHg
2. Depends upon altitude of residence

Question 14

What are the 5 causes of hypoxemia?

Answer 14

1 Hypoventilation

2 Low PIO2

3 Shunt

4 V/Q mismatch

5 Diffusion impairment

Question 15

which causes of hypoxemia are from decreased PAO2

Answer 15

1. hypoventilation
2. Low PIO2

Question 16

What are 5 causes of hypoventilation

Answer 16

• look at picture for 1-4
  5. anesthetic drugs

Question 17

1. During hypoventilation what will happen to PACO2?
2. A-a O2 difference?
3. Will giving pure oxygen (increasing FIO2) fix hypoxemia?

Answer 17

1. 2. 3. Yes, animal will respond

Question 18

during hypoventilation what will happen to

1. PAO2
2. PaO2

Answer 18

1. PAO2= decrease
2. PaO2= decrease

Question 19

during hypoventilation what will happen to

1. PACO2=
2. PaCO2=

Answer 19

1. PACO2= increase
2. PaCO2= increase

Question 20

1. Explain why PIO2 decreases as an animal moves to higher altitudes
2. Does FIO2 decrease?

Answer 20

1. atmospheric pressure will increase which will decrease PIO2
2. FIO2 stays the same!

Question 21

1. List the normal partial pressures of oxygen, carbon dioxide, water, and nitrogen in Inspired air
2. Alveolus

Answer 21

Question 22

1. List the normal partial pressures of oxygen, carbon dioxide, water, and nitrogen in arteries
2. tissues
3. veins

Answer 22

Question 23

How does an animal compensate for living at a high altitude

Answer 23

Increase alveolar ventilation, (hyperventilate)

Question 24

Convert gas content in percent to fractional concentration and partial pressure at various total pressures (altitudes) and water vapor pressures (100% saturation)

Question 25

what types of hypoxemia have an increased A-a oxygen partial pressure difference

Answer 25

* shunts * V/Q mismatch * Diffusion impairment

Question 26

What are 4 things that affect pulmonary diffusion

Answer 26

1. Alveolar Surface Area 2. Driving pressure * PA-\> Pa 3. Membrane thickness 4. Physical properties * Solubility * Molecular Weight (MW)

Question 27

1. what law is this 2. What do these stand for

Answer 27

D – Rate of gas diffusion ∆P – Partial pressure difference (C1-C2) A – cross-sectional area of surface S – Solubility of gas in the fluid X – Diffusion Coefficient, distance of diffusion path MW– Molecular weight of gas

Question 28

does CO2 or oxygen diffuse more?

Answer 28

CO2 diffuses 20 times faster than O2

Question 29

During exercise what will happen to PaO2

Answer 29

decreases because it is being dropped off in the tissues

Question 30

Explain how diffusion of oxygen is involved in the hypoxemia that develops in horses as they race.

Answer 30

* The major cause of the exercise-induced hypoxemia in the horse is a diffusion limitation. * During exercise, the combination of rapid pulmonary blood flows coupled with a much reduced venous oxygen content have been hypothesized to cause insufficient time to achieve complete equilibration of gas exchange across the capillary–alveolar interface