Question 1

Which of the following best explains why fetal hemoglobin (HbF) has a higher affinity for oxygen than adult hemoglobin (HbA)?

Accepted Answer

HbF contains two alpha and two gamma chains, which allow for greater oxygen binding at lower partial pressures.

Question 2

A newborn baby takes its first breath and begins to cry. Which physiological change is most directly facilitated by this action?

Accepted Answer

Decreased pressure in the right atrium and ventricle, leading to reversal of blood flow through the foramen ovale.

Question 3

Which equation correctly represents the conversion of carbon dioxide to bicarbonate in red blood cells?

Accepted Answer

$$CO_2 + H_2O$$ \rightarrow H_2CO_3 \rightarrow H^+ + $$HCO_3$$^-$$

Question 4

During deep sea diving, which physiological effect is most likely to occur due to increased atmospheric pressure?

Accepted Answer

Nitrogen narcosis due to increased nitrogen dissolution in body tissues.

Question 5

Which of the following factors will cause a rightward shift in the oxygen-hemoglobin dissociation curve, indicating decreased affinity for oxygen?

Accepted Answer

Increased temperature, increased $$P_{CO_2$}$$, and increased 2,3-BPG.

Question 6

A patient with sickle cell anemia has a mutation in the beta chain of hemoglobin. Which amino acid substitution is responsible for the sickling of red blood cells?

Accepted Answer

Glutamic acid is replaced by valine.

Question 7

Which of the following best describes the Bohr effect?

Accepted Answer

Carbon dioxide loading (via hydrogen ion formation) facilitates oxygen unloading from hemoglobin in the tissues.

Question 8

What is the primary reason that blood oxygen content decreases at high altitude?

Accepted Answer

Decreased partial pressure of oxygen in inspired air reduces oxygen diffusion into blood.

Question 9

Which of the following is NOT a normal adaptation in fetal circulation before birth?

Accepted Answer

Blood flows directly from the left ventricle to the placenta via the umbilical vein.

Question 10

Which of the following equations represents the binding of oxygen to hemoglobin in the lungs?

Accepted Answer

$$HHb + O_2$ \rightarrow $$HbO_2$$ + H^+$$

Question 11

A climber at high altitude experiences hypoxemia. Which of the following is the most likely cause?

Accepted Answer

Decreased inspired oxygen due to low atmospheric pressure.

Question 12

Which of the following statements about the Haldane effect is correct?

Accepted Answer

Oxygen loading in the lungs facilitates carbon dioxide unloading from hemoglobin.

Question 13

Which of the following is the most abundant form of hemoglobin in a healthy adult?

Accepted Answer

HbA ($$\$$alpha_2$$\$$beta_2$$)

Question 14

Which of the following is the main mechanism for carbon dioxide transport in the blood?

Accepted Answer

Converted to bicarbonate ions in red blood cells

Question 15

A patient is exposed to high levels of 2,3-bisphosphoglycerate (BPG). What effect will this have on the oxygen-hemoglobin dissociation curve?

Accepted Answer

Rightward shift, decreasing hemoglobin's affinity for oxygen.

Question 16

Which of the following is a direct consequence of increased temperature on hemoglobin's affinity for oxygen?

Accepted Answer

Hemoglobin releases oxygen more readily, resulting in a rightward shift of the dissociation curve.

Question 17

Which of the following best describes the role of the ductus arteriosus in fetal circulation?

Accepted Answer

It allows blood to bypass the lungs by connecting the pulmonary artery to the aorta.

Question 18

Which of the following is a common cause of hypoxemia due to shunting?

Accepted Answer

ARDS (Acute Respiratory Distress Syndrome)

Question 19

Which of the following blood gas measurements is considered normal for arterial $$P_{O_2$}$$?

Accepted Answer

$$80-100$$ mmHg

Respiratory System II: Hemoglobin, Gas Transport, Fetal Circulation, and Environmental Physiology

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