Ventilation Control

Question 1

Arteriovenous oxygen difference

• The difference between the … content of … blood and … blood
• For oxygen content of venous blood (Cv̄O2), switch “a” to “v̄”
• a-v̄O2 difference = … O2 - … O2
• Whole body, at rest ≈ 40-50 mL O2 / L blood
• Ca O2 - Cv̄O2 = 191.3 – 151.1 = 40.2 mL O 2 / L blood

Blood leaving the lungs:
* Has an oxygen content of … mL/100 mL blood
* Has an oxygen saturation of ~ …% to …%…

The a-v̄O2 difference at rest is approximately …mL/100 mL blood (i.e. 25% O2 uptake).
* During intensive aerobic exercise, increases to approximately … mL/100 mL blood (i.e. 75%-100%)

Answer 1

Arteriovenous oxygen difference

• The difference between the oxygen content of arterial blood and mixed venous blood
• For oxygen content of venous blood (Cv̄O2), switch “a” to “v̄”
• a-v̄O2 difference = Ca O2 - Cv̄O2
• Whole body, at rest ≈ 40-50 mL O2 / L blood
• Ca O2 - Cv̄O2 = 191.3 – 151.1 = 40.2 mL O 2 / L blood
• Blood leaving the lungs:
• Has an oxygen content of 16 to 24 mL/100 mL blood
• Has an oxygen saturation of ~ 95% to 98%…

The a-v̄O2 difference at rest is approximately 4-5 mL/100 mL blood (i.e. 25% O2 uptake).
* During intensive aerobic exercise, increases to approximately 15 to 20 mL/100 mL blood (i.e. 75%-100%)

Question 2

Carbon dioxide transport in the blood
* CO2 produced in cells diffuses into the blood and is transported to the lungs, where it is exhaled.

Blood carries CO2 in three ways:

Dissolved in solution
* ~…% of the total (…% in plasma and …% in red blood cells)

Transported as bicarbonate
* ~…% of total (…% in blood, …% in RBC)

Carbamino compounds (mostly bound to hemoglobin)
* ~…% of the total (…% in plasma and …% in red blood cells)

Answer 2

Carbon dioxide transport in the blood
* CO2 produced in cells diffuses into the blood and is transported to the lungs, where it is exhaled.

Blood carries CO2 in three ways:

Dissolved in solution
* ~10% of the total (5% in plasma and 5% in red blood cells)

Transported as bicarbonate
* ~65% of total (1% in blood, 65% in RBC)

Carbamino compounds (mostly bound to hemoglobin)
* ~25% of the total (5% in plasma and 20% in red blood cells)

Question 3

Where does the CO2 come from?

• from the glycolysis pathway
• from the TCA cycle

Carbon dioxide transport in the blood

• CO2 produced in cells diffuses into the blood and is transported to the lungs, where it is exhaled.
• Blood carries CO2 in three ways:

…
* ~10% of the total (…% in plasma and …% in red blood cells)

…
* ~65% of total

… (…)
* ~25% of the total (…% in plasma and …% in red blood cells)

Answer 3

Where does the CO2 come from?

• from the glycolysis pathway
• from the TCA cycle

Carbon dioxide transport in the blood

• CO2 produced in cells diffuses into the blood and is transported to the lungs, where it is exhaled.
• Blood carries CO2 in three ways:

Dissolved in solution
* ~10% of the total (5% in plasma and 5% in red blood cells)

Transported as bicarbonate
* ~65% of total

Carbamino compounds (mostly bound to hemoglobin)
* ~25% of the total (5% in plasma and 20% in red blood cells)

Question 4

CO2 goes into your blood
Some dissolved in plasma, the rest goes inside the RBC
Most of it will be converted to bicarb

Becomes carbonic acid (CO2 + H2O) with CARBONIC ANHYDRASE
decomposed into H+ and bicarb
bicarb goes outside to the plasma, and is switched with Cl-

5% disovled into plasma
5% onto Hb
1% into bicarb

65% into bicarb
5% dissolved in RBC
20% attached to Hb

Question 5

At the side of the lungs, EVERYTHING is reversed

bicarb goes back inside the RBC, chloride shift
+ H and goes into carbonic acid
then into CO2 and H2O
CO2 delivered to the lungs

bicarb in plasma 1%, goes inside and turns into acid then CO2
the 20% Hb in the RBC, goes back to Hb and CO2

Question 6

Carbon dioxide transport

1. CO2 produced by cellular metabolism diffuses into the bloodstream.
2. CO2 combines with … (…) in the presence of the … (present in red blood cells) to form …
3. … then dissociates into … (…) and …(…).
4. Bicarbonate ions act as a buffer by reacting with excess hydrogen ions to form carbonic acid, which can then be converted back to CO2 and exhaled by the lungs.

• Plasma proteins … in the bicarbonate buffering system, they can … by acting as a reservoir for …

For example, …, the most abundant plasma protein, has ionizable groups that can bind or release hydrogen ions, contributing to the buffering capacity of the blood.

• Overall, while plasma proteins do not serve as …, they can still play a role in maintaining … in the blood by participating in other aspects of the buffering system

Answer 6

Carbon dioxide transport

1. CO2 produced by cellular metabolism diffuses into the bloodstream.
2. CO2 combines with water (H2O) in the presence of the enzyme carbonic anhydrase (present in red blood cells) to form carbonic acid (H2CO3).
3. Carbonic acid then dissociates into hydrogen ions (H+) and bicarbonate ions (HCO3-).
4. Bicarbonate ions act as a buffer by reacting with excess hydrogen ions to form carbonic acid, which can then be converted back to CO2 and exhaled by the lungs.

• While plasma proteins do not directly participate in the bicarbonate buffering system, they can indirectly influence pH regulation by acting as a reservoir for hydrogen ions.

For example, albumin, the most abundant plasma protein, has ionizable groups that can bind or release hydrogen ions, contributing to the buffering capacity of the blood.

• Overall, while plasma proteins do not serve as direct buffers for CO2, they can still play a role in maintaining pH homeostasis in the blood by participating in other aspects of the buffering system

Question 7

EXAMMMMM
Buffers resist changes in … (concentration of [H+ ])
* When pH drops, buffers …
* When pH increases, buffers …

Chemical buffer systems
* …
* … (…)
* …

Physiological buffer systems
* …

• Increasing ventilation lowers …, allowing more … to diffuse into the lung and to be …

Answer 7

Buffers resist changes in pH (concentration of [… ])
* When pH drops, buffers absorb H +
* When pH increases, buffers release H +

Chemical buffer systems - PBP
* Bicarbonate
* Protein (hemoglobin)
* Phosphate

Physiological buffer systems
* Ventilatory

• Increasing ventilation lowers P A CO2, allowing more CO 2 to diffuse into the lung and to be exhaled to the environment.

Question 8

• The partial pressure of O2 determines …,= which determines the …;
• Gas is exchanged in the lungs and muscles via …;
• O2 moves from high partial pressures to low.
• The majority of O2 is transported …;
• Exercise increases muscle oxygen uptake, which leads to a greater …
• The majority of CO2 in blood is transported as …;
• The binding of O2 to Hb promotes …;
• The lungs help buffer pH changes in blood by removing …

Answer 8

• The partial pressure of O2 determines O2 saturation,= which determines the O2 content of blood;
• Gas is exchanged in the lungs and muscles via diffusion;
• O2 moves from high partial pressures to low.
• The majority of O2 is transported bound to hemoglobin;
• Exercise increases muscle oxygen uptake, which leads to a greater arteriovenous oxygen difference
• The majority of CO2 in blood is transported as bicarbonate;
• The binding of O2 to Hb promotes CO2 and H+ release;
• The lungs help buffer pH changes in blood by removing CO2