Question 1

Values of $\mathrm { pO } _ { 2 } = 116 \mathrm {~mm} \mathrm { Hg }$ and $\mathrm { pCO } _ { 2 } = 27 \mathrm {~mm}$ Hg most closely describe which of the following?
A. Atmospheric air
B. Alveolar air
C. Blood in the left heart
D. Blood in the right heart
E. Expired air

Accepted Answer

E

Question 2

$$\text { Systemic arterial } \mathrm { PO } _ { 2 } \text { of approximately } 100 \mathrm { mmHg }$$

Accepted Answer

A

Question 3

$$\text { Systemic arterial } \mathrm { pO } _ { 2 } > 120 \mathrm { mmHg }$$

Accepted Answer

B

Question 4

$$\text { Systemic arterial } \mathrm { pCO } _ { 2 } > \text { normal }$$

Accepted Answer

The answer of \[\text { Systemic arterial } \mathrm {...

Question 5

A human experiment is being performed where forearm blood flow is being measured under a variety of conditions. The forearm is warmed, resulting in an increase in blood flow. Which of the following occurs? A. Tissue interstitial $\mathrm { PO } _ { 2 } \mathrm { w }$ ill increase
B. Tissue interstitial $\mathrm { PCO } _ { 2 }$ will increase
C. Tissue $\mathrm { pH }$ will decrease

Accepted Answer

The answer of A human experiment is being performed where...

Question 6

Blood gas measurements in a patient on room air indicates that his systemic arterial oxygen content is normal (19.5 ml O₂/100 ml blood), but his systemic venous oxygen content is low (6 ml O₂/100 ml blood). This is characteristic of which of the following?
A)V/Q less than normal
B)An increase in physiological dead space
C)Pulmonary edema
D)Low hemoglobin concentration
E)Low cardiac output

Accepted Answer

This scenario indicates a low systemic venous oxygen content, which suggests that tissues are extracting more oxygen than usual, a common characteristic of low cardiac output. In conditions of low cardiac output, the body compensates by extracting more oxygen from the blood to meet metabolic demands, leading to a lower venous oxygen content.

Question 7

If a lung having a normal ventilation-perfusion ratio $( = 1 )$ suddenly develops a ventilation/perfusion ratio of $< 1$, which of the following will occur?
A. A decrease in arterial $\mathrm { pO } _ { 2 }$
B. An increase in alveolar $\mathrm { pO } _ { 2 }$
C. A decrease in cardiac output
D. A decrease in arterial $\mathrm { pCO } _ { 2 }$

Accepted Answer

The answer of If a lung having a normal ventilation-perfusion...

Question 8

For a patient at sea level (barometric pressure = 760 mm Hg) and breathing 40%, oxygen calculate alveolar pO₂ is which of the following?
A)149
B)159
C)235
D)285
E)304

Accepted Answer

The answer of For a patient at sea level (barometric...

Question 9

Twin patients, $X$ and $Y$, both have resp irations of 12 breaths/min, tidal volumes of 500 $\mathrm { mL }$, and dead space of $100 \mathrm {~mL}$. Patient $X$ 's resp iratory rate decreases by half and the tidal volume doubles. Patient Y's resp iratory rate doubles and the tidal volume decreases by half. After 2 minutes, what conditions would best describe their alveolar gases, as compared with normal?
Patient X Alveolar Ventilation $\quad \underline { \text { Patient } \mathrm { Y } }$ Alveolar Ventilation
$\begin{array} { l  } 
&\text { Alveolar } \mathrm{pO}_{2}&\text { Alveolar } \mathrm{pCO}_{2}&\text { Alveolar } \mathrm{pO}_{2}&\text { Alv eolar } \mathrm{pCO}_{2}\
A.&\uparrow&↓&\uparrow&↓\
B.&↓&\uparrow&↓&↓\
C.&\uparrow&↓&↓&\uparrow\
D.&\uparrow&\uparrow&\uparrow&\uparrow\
E.&\downarrow&\uparrow&\downarrow&\uparrow\
\end{array}$

Accepted Answer

The answer of Twin patients, $X$ and $Y$, both have...

Question 10

A child has been eating M&Ms (plain) and inhaled one down his airway, blocking his left bronchiole. Which of the following will describe the changes that occur? $\begin{array} { l  } 
&\text { Left Lung Alveolar } \mathrm{pCO}_{2}&\text { Left Lung Alveolar } \mathrm{pO}_{2}&\text { Systemic Asterial } \mathrm{pO}_{2}\
A.&\uparrow&\uparrow&\uparrow\
B.&\uparrow&\uparrow&\leftrightarrow\
C.&\uparrow& \downarrow& \downarrow\
D.&\uparrow&\leftrightarrow&\uparrow&\
E.& \downarrow& \downarrow& \downarrow\
\end{array}$

Accepted Answer

The answer of A child has been eating M&Ms (plain)...

Question 11

If alveolar surface area is decreased 50% and pulmonary edema leads to a doubling of diffusion distance, how does diffusion of oxygen compare with normal?
A)25% increase
B)50% increase
C)25% decrease
D)50% decrease
E)75% decrease

Accepted Answer

The diffusion of oxygen is directly proportional to the surface area and inversely proportional to the diffusion distance. A 50% decrease in alveolar surface area and a doubling of diffusion distance would lead to a 75% decrease in oxygen diffusion, as per the formula for diffusion capacity (Vgas = A/T * D * (P1 - P2)), where A is surface area and T is thickness or diffusion distance.

Question 12

A person with normal lungs at sea level $( 760 \mathrm {~mm} \mathrm { Hg } )$ is breathing $50 \%$ oxygen. What is the approximate alveolar $\mathrm { pO } _ { 2 }$ ?
A. 100
B. 159
C. 310
D. 330
E. 380

Accepted Answer

The answer of A person with normal lungs at sea...

Question 13

In an individual, the $\mathrm { pO } _ { 2 }$ and $\mathrm { pCO } _ { 2 }$ in different alveoli varies as follows:
$\begin{array} { l  } 
&\mathrm{pO}_{2}&\mathrm{pCO}_{2}\
\hline  \text {Alveolus A }&100&40\
 \text { Alveolus B }&40&45\
 \text { Alveolus C }&150&0\
\end{array}$
Which of the following statements is true?
A. Alveolus $\mathrm { B }$ is indicative of a dead space ventilation
B. Alveolus $\mathrm { C }$ is indicative of pulmonary shunt
C. Breathing $100 \% \mathrm { O } _ { 2 }$ would increase $\mathrm { PO } _ { 2 }$ in alveolus $\mathrm { C }$
D. Hyperventilation would increase $\mathrm { PO } _ { 2 }$ in alveolus $\mathrm { B }$

Accepted Answer

The answer of In an individual, the \(\mathrm { pO...

Question 14

A patient has a normal oxygen partial pressure and content in pulmonary venous blood but his systemic arterial blood shows a significantly lower than normal oxygen partial pressure and content. This is diagnostic of which of the following?
A)Diffusion limitation
B)Right-to-left shunt
C)Pulmonary ventilation/perfusion nonuniformity
D)Stagnant hypoxia (low cardiac output)

Accepted Answer

A right-to-left shunt is the only option that would result in normal oxygenation of blood in the pulmonary veins (which bypasses the shunt) but decreased oxygenation in the systemic arterial blood. Diffusion limitation, pulmonary ventilation/perfusion nonuniformity, and stagnant hypoxia would all affect both pulmonary venous and systemic arterial oxygen levels.

Quiz 40: Physical Principles of Gas Exchange; Diffusion of Oxygen and Carbon Dioxide Through the Respiratory Membrane

Values of $\mathrm { pO } _ { 2 } = 116 \mathrm {~mm} \mathrm { Hg }$ and $\mathrm { pCO } _ { 2 } = 27 \mathrm {~mm}$ Hg most closely describe which of the following? A. Atmospheric air B. Alveolar air C. Blood in the left heart D. Blood in the right heart E. Expired air

$\text { Systemic arterial } \mathrm { PO } _ { 2 } \text { of approximately } 100 \mathrm { mmHg }$

$\text { Systemic arterial } \mathrm { pO } _ { 2 } > 120 \mathrm { mmHg }$

$\text { Systemic arterial } \mathrm { pCO } _ { 2 } > \text { normal }$

Blood gas measurements in a patient on room air indicates that his systemic arterial oxygen content is normal (19.5 ml O₂/100 ml blood) , but his systemic venous oxygen content is low (6 ml O₂/100 ml blood) . This is characteristic of which of the following?

For a patient at sea level (barometric pressure = 760 mm Hg) and breathing 40%, oxygen calculate alveolar pO₂ is which of the following?

If alveolar surface area is decreased 50% and pulmonary edema leads to a doubling of diffusion distance, how does diffusion of oxygen compare with normal?

A person with normal lungs at sea level $( 760 \mathrm {~mm} \mathrm { Hg } )$ is breathing $50 \%$ oxygen. What is the approximate alveolar $\mathrm { pO } _ { 2 }$ ? A. 100 B. 159 C. 310 D. 330 E. 380

A patient has a normal oxygen partial pressure and content in pulmonary venous blood but his systemic arterial blood shows a significantly lower than normal oxygen partial pressure and content. This is diagnostic of which of the following?

Quiz 40: Physical Principles of Gas Exchange; Diffusion of Oxygen and Carbon Dioxide Through the Respiratory Membrane

Systemic arterial PO2 of approximately 100mmHg\text { Systemic arterial } \mathrm { PO } _ { 2 } \text { of approximately } 100 \mathrm { mmHg } Systemic arterial PO2​ of approximately 100mmHg

Systemic arterial pO2>120mmHg\text { Systemic arterial } \mathrm { pO } _ { 2 } > 120 \mathrm { mmHg } Systemic arterial pO2​>120mmHg

Systemic arterial pCO2> normal \text { Systemic arterial } \mathrm { pCO } _ { 2 } > \text { normal } Systemic arterial pCO2​> normal