Question 1

In which of the following forms is/are carbon dioxide transported by the blood? 1) Chemically combined with proteins 2) Ionized as bicarbonate (HCO₃^-) 3) Simple physical solution

Accepted Answer

Carbon dioxide is transported in the blood in three main forms: chemically combined with proteins (as carbaminohemoglobin), ionized as bicarbonate (which is the most significant form), and dissolved as a simple physical solution in the plasma.

Question 2

Given the following blood parameters, compute the total O₂ content (dissolved + HbO₂) of the blood in ml/dl: Hb = 18; PO₂ = 40 mm Hg; SO₂ = 73%.

Accepted Answer

Known values are (1) PO₂, (2) total hemoglobin content (g/dl), and (3) hemoglobin saturation. Given these values, the following equation can be applied:

Question 3

Why is it necessary to keep the patient's PaO₂ greater than 60 mm Hg?

Accepted Answer

With a PO₂ lower than 60 mm Hg, the curve steepens dramatically. Here, in the normal operating range of the tissues, even a small drop in PO₂ causes a large drop in SaO₂, indicating a decreasing affinity for O₂. This normal decrease in the affinity of hemoglobin for O₂ helps release large amounts of O₂ to the tissue, where the PO₂ is low. This also explains why it is necessary to keep the PaO₂ higher than 60 mm Hg in clinical practice.

Question 4

In which of the following conditions will erythrocyte concentration of 2,3-DPG be decreased?

Accepted Answer

Erythrocyte concentrations of 2,3-DPG in banked blood decrease over time. After a week of storage, the 2,3-DPG level may be less than one-third of the normal value.

Question 5

At a PaO₂ of 65 mm Hg, what is the approximate saturation of Hb with O₂?

Accepted Answer

If some abnormality reduced the PaO₂ to 65 mm Hg, the SaO₂ would still be approximately 90%.

Question 6

Compared to normal levels, a shift in the HbO₂ curve to the right has which of the following effects? 1) The affinity of Hb for O₂ decreases. 2) The Hb saturation for a given PO₂ falls. 3) The Hb saturation for a given PO₂ rises.

Accepted Answer

When the HbO₂ curve shifts to the right, it means that the affinity of Hb for O₂ decreases. This is because it takes a higher PO₂ concentration to achieve the same level of Hb saturation as in the normal curve. Therefore, option 1 is correct. As for option 2, it is also correct because the Hb saturation for a given PO₂ falls due to the decreased affinity. However, option 3 is incorrect because the Hb saturation for a given PO₂ cannot rise when the curve shifts to the right.

Question 7

The affinity of Hb for carbon monoxide (CO) is approximately how many times greater than its affinity for O₂?

Accepted Answer

Carboxyhemoglobin (HbCO) is the chemical combination of hemoglobin with CO. Hemoglobin's affinity for CO is more than 200 times greater than it is for O₂.

Question 8

Given the following blood parameters, compute the total O₂ content (dissolved + HbO₂) of the blood in ml/dl: Hb = 16; PO₂ = 625 Hg; SO₂ = 100%.

Accepted Answer

The respiratory therapist obtains a sample of arterial blood from a patient breathing 100% O₂. The PO₂ is 625 mm Hg, Hb is 16 g/dl, and the O₂ saturation is 100%. To compute the total O₂ content, the respiratory therapist should apply the aforementioned equation as follows:

Question 9

Which of the following is true regarding fetal hemoglobin (HbF)?

Accepted Answer

HbF has a greater affinity for O₂ than does normal adult Hb, as manifested by a leftward shift of the HbO₂ curve. Given the low PO₂ values available to the fetus in utero, this leftward shift aids O₂ loading at the placenta. Because of the relatively low pH of the fetal environment, O₂ unloading at the cellular level is not greatly affected.

Question 10

Which of the following increases the affinity of Hb for O₂? 1) Decreased 2,3-DPG 2) Decreased PCO₂ 3) Increased pH 4) Increased temperature

Accepted Answer

The answer of Which of the following increases the affinity...

Question 11

What is the effect of an elevated intracellular 2,3-DPG concentration?

Accepted Answer

Increased 2,3-DPG concentrations shift the HbO₂ curve to the right, promoting O₂ unloading.

Question 12

The oxidation of the Hb molecule's iron ions to the ferric state (Fe³⁺) results in which of the following? 1) Form of anemia called sickle cell anemia 2) Formation of methemoglobin (metHb) 3) Inability of metHb to bind with O₂

Accepted Answer

The oxidation of the Hb molecule's iron ions to the ferric state results in the formation of methemoglobin (metHb), which cannot bind oxygen, not sickle cell anemia, which is caused by a genetic mutation in the hemoglobin protein.

Question 13

A patient has a whole-body O₂ consumption of 320 ml/min and a measured CaO₂ - CO₂of 8 ml/dl. What is the cardiac output?

Accepted Answer

Fick equation:

Question 14

Which of these statements applies to the following reaction: Prot-NH₂ + CO₂ Prot-NHCOO^- + H⁺?

Accepted Answer

A small amount of the carbon dioxide leaving the tissues combines with plasma proteins to form these carbamino compounds.

Question 15

A patient has a P₅₀ value of 29 mm Hg. What does this indicate?

Accepted Answer

Conditions that cause a decrease in Hb affinity for O₂ (a shift of the HbO₂ curve to the right) increase the P₅₀ to higher than normal. A normal P₅₀ is 26 mm Hg.

Question 16

What role does the Bohr effect play in O₂ transport?

Accepted Answer

The Bohr effect enhances O₂ loading in the lungs and O₂ unloading in the tissues.

Question 17

According to the Fick principle, if O₂ consumption remains constant, an increase in cardiac output will manifest itself as which of the following?

Accepted Answer

If the cardiac output rises and O₂ consumption remains constant, the C(a-)O₂ will fall proportionately.

Question 18

According to the Bohr effect, when the pH drops, what happens? 1) The affinity of Hb for O₂ decreases. 2) The Hb saturation for a given PO₂ falls. 3) The Hb saturation for a given PO₂ rises.

Accepted Answer

The Bohr effect describes how a decrease in pH (or an increase in CO2 concentration) leads to a decrease in the affinity of hemoglobin (Hb) for oxygen (O2), which in turn causes a decrease in Hb saturation for a given partial pressure of oxygen (PO2). This means that under more acidic conditions (lower pH), hemoglobin releases more oxygen to the tissues.

Question 19

What is the approximate normal CaO₂ - CO₂in a healthy adult at rest?

Accepted Answer

As indicated in Table 12-2, the difference between the normal arterial and venous O₂ contents is approximately 5 ml/dl.

Question 20

What happens when the temperature of the blood rises? 1) The Hb saturation for a given PO₂ falls. 2) The HbO₂ curve shifts to the right. 3) The affinity of Hb for O₂ increases.

Accepted Answer

1) When the temperature of the blood rises, the saturation of hemoglobin (Hb) for a given partial pressure of oxygen (PO2) decreases, meaning less oxygen is bound to hemoglobin at a given PO2. 2) This phenomenon is represented by a rightward shift of the oxygen-hemoglobin dissociation curve, indicating a decreased affinity of Hb for oxygen at higher temperatures, facilitating oxygen release to tissues.

Quiz 12: Gas Exchange and Transport

In which of the following forms is/are carbon dioxide transported by the blood? 1) Chemically combined with proteins 2) Ionized as bicarbonate (HCO₃^-) 3) Simple physical solution

Given the following blood parameters, compute the total O₂ content (dissolved + HbO₂) of the blood in ml/dl: Hb = 18; PO₂ = 40 mm Hg; SO₂ = 73%.

Why is it necessary to keep the patient's PaO₂ greater than 60 mm Hg?

In which of the following conditions will erythrocyte concentration of 2,3-DPG be decreased?

At a PaO₂ of 65 mm Hg, what is the approximate saturation of Hb with O₂?

Compared to normal levels, a shift in the HbO₂ curve to the right has which of the following effects? 1) The affinity of Hb for O₂ decreases. 2) The Hb saturation for a given PO₂ falls. 3) The Hb saturation for a given PO₂ rises.

The affinity of Hb for carbon monoxide (CO) is approximately how many times greater than its affinity for O₂?

Given the following blood parameters, compute the total O₂ content (dissolved + HbO₂) of the blood in ml/dl: Hb = 16; PO₂ = 625 Hg; SO₂ = 100%.

Which of the following is true regarding fetal hemoglobin (HbF) ?

Which of the following increases the affinity of Hb for O₂? 1) Decreased 2,3-DPG 2) Decreased PCO₂ 3) Increased pH 4) Increased temperature

What is the effect of an elevated intracellular 2,3-DPG concentration?

The oxidation of the Hb molecule's iron ions to the ferric state (Fe³⁺) results in which of the following? 1) Form of anemia called sickle cell anemia 2) Formation of methemoglobin (metHb) 3) Inability of metHb to bind with O₂

A patient has a whole-body O₂ consumption of 320 ml/min and a measured CaO₂ - CO₂of 8 ml/dl. What is the cardiac output?

Which of these statements applies to the following reaction: Prot-NH₂ + CO₂ Prot-NHCOO^- + H⁺?

A patient has a P₅₀ value of 29 mm Hg. What does this indicate?

What role does the Bohr effect play in O₂ transport?

According to the Fick principle, if O₂ consumption remains constant, an increase in cardiac output will manifest itself as which of the following?

According to the Bohr effect, when the pH drops, what happens? 1) The affinity of Hb for O₂ decreases. 2) The Hb saturation for a given PO₂ falls. 3) The Hb saturation for a given PO₂ rises.

What is the approximate normal CaO₂ - CO₂in a healthy adult at rest?

What happens when the temperature of the blood rises? 1) The Hb saturation for a given PO₂ falls. 2) The HbO₂ curve shifts to the right. 3) The affinity of Hb for O₂ increases.

Quiz 12: Gas Exchange and Transport

In which of the following forms is/are carbon dioxide transported by the blood? 1) Chemically combined with proteins 2) Ionized as bicarbonate (HCO3-) 3) Simple physical solution

Given the following blood parameters, compute the total O2 content (dissolved + HbO2) of the blood in ml/dl: Hb = 18; PO2 = 40 mm Hg; SO2 = 73%.

Why is it necessary to keep the patient's PaO2 greater than 60 mm Hg?

In which of the following conditions will erythrocyte concentration of 2,3-DPG be decreased?

At a PaO2 of 65 mm Hg, what is the approximate saturation of Hb with O2?

Compared to normal levels, a shift in the HbO2 curve to the right has which of the following effects? 1) The affinity of Hb for O2 decreases. 2) The Hb saturation for a given PO2 falls. 3) The Hb saturation for a given PO2 rises.

The affinity of Hb for carbon monoxide (CO) is approximately how many times greater than its affinity for O2?

Given the following blood parameters, compute the total O2 content (dissolved + HbO2) of the blood in ml/dl: Hb = 16; PO2 = 625 Hg; SO2 = 100%.

Which of the following is true regarding fetal hemoglobin (HbF) ?

Which of the following increases the affinity of Hb for O2? 1) Decreased 2,3-DPG 2) Decreased PCO2 3) Increased pH 4) Increased temperature

What is the effect of an elevated intracellular 2,3-DPG concentration?

The oxidation of the Hb molecule's iron ions to the ferric state (Fe3+) results in which of the following? 1) Form of anemia called sickle cell anemia 2) Formation of methemoglobin (metHb) 3) Inability of metHb to bind with O2

A patient has a whole-body O2 consumption of 320 ml/min and a measured CaO2 - CO2 of 8 ml/dl. What is the cardiac output?

Which of these statements applies to the following reaction: Prot-NH2 + CO2 Prot-NHCOO- + H+?

A patient has a P50 value of 29 mm Hg. What does this indicate?

What role does the Bohr effect play in O2 transport?

According to the Fick principle, if O2 consumption remains constant, an increase in cardiac output will manifest itself as which of the following?

According to the Bohr effect, when the pH drops, what happens? 1) The affinity of Hb for O2 decreases. 2) The Hb saturation for a given PO2 falls. 3) The Hb saturation for a given PO2 rises.

What is the approximate normal CaO2 - CO2 in a healthy adult at rest?

What happens when the temperature of the blood rises? 1) The Hb saturation for a given PO2 falls. 2) The HbO2 curve shifts to the right. 3) The affinity of Hb for O2 increases.

In which of the following forms is/are carbon dioxide transported by the blood? 1) Chemically combined with proteins 2) Ionized as bicarbonate (HCO₃^-) 3) Simple physical solution

Given the following blood parameters, compute the total O₂ content (dissolved + HbO₂) of the blood in ml/dl: Hb = 18; PO₂ = 40 mm Hg; SO₂ = 73%.

Why is it necessary to keep the patient's PaO₂ greater than 60 mm Hg?

At a PaO₂ of 65 mm Hg, what is the approximate saturation of Hb with O₂?

Compared to normal levels, a shift in the HbO₂ curve to the right has which of the following effects? 1) The affinity of Hb for O₂ decreases. 2) The Hb saturation for a given PO₂ falls. 3) The Hb saturation for a given PO₂ rises.

The affinity of Hb for carbon monoxide (CO) is approximately how many times greater than its affinity for O₂?

Given the following blood parameters, compute the total O₂ content (dissolved + HbO₂) of the blood in ml/dl: Hb = 16; PO₂ = 625 Hg; SO₂ = 100%.

Which of the following increases the affinity of Hb for O₂? 1) Decreased 2,3-DPG 2) Decreased PCO₂ 3) Increased pH 4) Increased temperature

The oxidation of the Hb molecule's iron ions to the ferric state (Fe³⁺) results in which of the following? 1) Form of anemia called sickle cell anemia 2) Formation of methemoglobin (metHb) 3) Inability of metHb to bind with O₂

A patient has a whole-body O₂ consumption of 320 ml/min and a measured CaO₂ - CO₂of 8 ml/dl. What is the cardiac output?

Which of these statements applies to the following reaction: Prot-NH₂ + CO₂ Prot-NHCOO^- + H⁺?

A patient has a P₅₀ value of 29 mm Hg. What does this indicate?

What role does the Bohr effect play in O₂ transport?

According to the Fick principle, if O₂ consumption remains constant, an increase in cardiac output will manifest itself as which of the following?

According to the Bohr effect, when the pH drops, what happens? 1) The affinity of Hb for O₂ decreases. 2) The Hb saturation for a given PO₂ falls. 3) The Hb saturation for a given PO₂ rises.

What is the approximate normal CaO₂ - CO₂in a healthy adult at rest?

What happens when the temperature of the blood rises? 1) The Hb saturation for a given PO₂ falls. 2) The HbO₂ curve shifts to the right. 3) The affinity of Hb for O₂ increases.