S3_L5: Gas Transport

Question 1

TRUE OR FALSE: Of the O2 that diffuses from the alveoli, 97.5% combines with hemoglobin and 1.5% dissolves in plasma

Answer 1

False, its 98.5% that combines with hemoglobin

Question 2

When four O2’s are bound to hemoglobin, it is ___% saturated, and with fewer O2’s, it is partially saturated.

Answer 2

100

Hemoglobin molecule can transport up to 4 O2’s

Question 3

Number of iron atoms in 1 hemoglobin molecule

Answer 3

Four

4 O2’s will bind to the 4 iron atoms

Question 4

TRUE OR FALSE: Hemoglobin’s affinity for O2 increases as O2’s saturation decreases

Answer 4

False, there’s a direct relationship between the affinity of hemoglobin & oxygen saturation

Question 5

This is used to determine how much partial pressure of oxygen could make the hemoglobin be filled/saturated at a certain amount of blood pressure

Answer 5

Oxygen-Hemoglobin Dissociation Curve

Question 6

TRUE OR FALSE: When O2 is unbounded at tissue level, oxyhemoglobin (Hb O2) becomes deoxyhemoglobin (Hb)

Answer 6

True

Hb + O2 -> Hb O2

Question 7

The oxygen-hemoglobin dissociation curve is an S-shaped curve with a (1)___ slope at high PO2’s and (2)___ slope at lower PO2’s.

Answer 7

1. flat
2. steep

Question 8

TRUE OR FALSE: The PO2 is lower in vigorously contracting muscles than in resting muscles

Answer 8

True

Because more O2 is unloaded to the working muscles

Question 9

TRUE OR FALSE: Exercise increases the pH, which increases acidity, causing a release of lactic acid

Answer 9

False, exercise decreases the pH

Question 10

TRUE OR FALSE: Exercise increases temperature, PCO2, and bisphosphoglycerate (BPG)

Answer 10

True

Question 11

The Oxygen-Hemoglobin Dissociation Curve shifts to ___ when exercising due to decreased pH, increased temperature, PCO2, and BPG.

Answer 11

right and downwards

-increased oxygen unloading, unload O2 at a faster rate, 95 or 93% saturated

Question 12

The Oxygen-Hemoglobin Dissociation Curve shifts to the ___ as a response to decreased temperature, PCO2, BPG, and increased pH.

Answer 12

Left and upwards

-At decreased temperatures, hemoglobin’s affinity for oxygen is higher and less oxygen is released, which favors O2 conservation and the blood becomes alkaline. 85% saturated

Question 13

Enumerate the 3 ways of CO2 transport from tissue cells:

Answer 13

1. Dissolved in plasma (7%)
2. Bound to hemoglobin as carbaminohemoglobin (23%)
3. Converted to bicarbonate ions (70%)

Question 14

Carbaminohemoglobin forms in regions of ___ PCO2

Answer 14

high

Question 15

TRUE OR FALSE: In the lungs with lower PCO2, carbon dioxide dissociates from carbaminohemoglobin and returns to H20+CO2. Then, CO2 diffuses into the alveoli.

Answer 15

True

Question 16

In regions with high PCO2, CO2 enters the RBC and binds with H2O from the RBC to form carbonic acid. This reaction is catalyzed by this enzyme.

Answer 16

carbonic anhydrase

Question 17

In the plasma, ____ acts as a buffer to control blood pH.

Answer 17

bicarbonate ions

Plasma & RBC become acidic since there are lactic acid and free flowing hydrogen ions
there. As this should not happen, bicarbonate ions will buffer the plasma by exiting & exchanging with chloride ions to maintain electrical neutrality (chloride shift occurs).

Question 18

As carbonic acid is unstable, it will dissociate into ___ and ___.

Answer 18

hydrogen ions and bicarbonate ions

Question 19

TRUE OR FALSE: When hemoglobin is saturated with oxygen, its affinity for carbon dioxide increases.

Answer 19

False, its affinity for carbon dioxide decrease

Oxygen loading facilitates carbon dioxide unloading from hemoglobin

Question 20

___ is the interaction between O2 loading and CO2 unloading from hemoglobin at the alveolocapillary level. Once O2 combines with hemoglobin, there is the H2 that is bounded to hemoglobin because of CO2 transport. O2 will kick out H2 and H2 will combine with CO2 later on.

Answer 20

Haldane Effect

Question 21

___ is the interaction between hydrogen ion binding and hemoglobin’s affinity for oxygen: CO2 loading, through the formation of hydrogen ions, facilitates O2 unloading from hemoglobin. It is the effect of decreased pH on O2 unloading.

Answer 21

Bohr Effect

Question 22

In regions with low PCO2, such as the lungs, carbonic acid breaks down into CO2 and water. This reverse reaction is catalyzed by ____.

Answer 22

carbonic anhydrase

Question 23

In the reverse reaction in the lungs, ___ breaks down into CO2 and H2O. As PCO2 is higher in the RBC than the alveolus, CO2 will diffuse toward the alveolus and H2O will remain in the RBC.

Answer 23

carbonic acid