Question 1

Which of the following best explains why hemoglobin can transport up to four oxygen molecules?

Accepted Answer

Hemoglobin has four polypeptide chains, each with a heme group containing iron.

Question 2

A patient is experiencing acidosis due to respiratory failure. Which chemical equation best represents the buffer system that helps resist changes in blood pH?

Accepted Answer

$\mathrm{CO_2} + \mathrm{H_2O} \leftrightarrow \mathrm{H_2CO_3} \leftrightarrow \mathrm{HCO_3^-} + \mathrm{H^+}$

Question 3

During vigorous exercise, why do $\mathrm{P_{O_2}}$ and pH remain relatively constant despite a large increase in ventilation?

Accepted Answer

Increased ventilation matches the increased metabolic demand, maintaining homeostasis.

Question 4

Which of the following would cause a rightward shift in the oxygen-hemoglobin dissociation curve?

Accepted Answer

Increased temperature, increased $\mathrm{P_{CO_2}}$, decreased pH, and increased BPG.

Question 5

A person at high altitude experiences headaches and shortness of breath. Which physiological response helps compensate for the lower $\mathrm{P_{O_2}}$?

Accepted Answer

Increased erythropoietin (EPO) production by the kidneys, leading to more RBCs.

Question 6

Which form of hypoxia is most likely in a patient with cyanide poisoning?

Accepted Answer

Histotoxic hypoxia

Question 7

What is the primary effect of hyperventilation on blood chemistry?

Accepted Answer

Decreased $\mathrm{P_{CO_2}}$ leading to increased blood pH (alkalosis)

Question 8

Which neural group is primarily responsible for generating the basic rhythm of breathing?

Accepted Answer

Ventral respiratory group (VRG)

Question 9

A patient with chronic bronchitis is likely to have which of the following symptoms?

Accepted Answer

Frequent pulmonary infections and excessive mucus production

Question 10

Which equation correctly represents the formation of carbaminohemoglobin?

Accepted Answer

$\mathrm{CO_2} + \mathrm{Hb} \leftrightarrow \mathrm{HbCO_2}$

Question 11

Which of the following best describes the Bohr effect?

Accepted Answer

Increased $\mathrm{P_{CO_2}}$ and decreased pH weaken the bond between hemoglobin and oxygen, enhancing oxygen unloading.

Question 12

Which of the following is a consequence of the chloride shift in systemic capillaries?

Accepted Answer

Bicarbonate ions ($\mathrm{HCO_3^-}$) diffuse out of RBCs, and chloride ions ($\mathrm{Cl^-}$) move in to maintain electrical neutrality.

Question 13

A patient with obstructive sleep apnea is most likely to benefit from which intervention?

Accepted Answer

Continuous positive airway pressure (CPAP) device

Question 14

Which of the following is true regarding the oxygen-hemoglobin dissociation curve?

Accepted Answer

It is S-shaped, reflecting cooperative binding of oxygen to hemoglobin.

Question 15

Which of the following best describes the effect of increased $\mathrm{P_{CO_2}}$ on breathing rate?

Accepted Answer

It stimulates central chemoreceptors, increasing depth and rate of breathing.

Question 16

Which type of lung cancer is most likely to metastasize early and contains lymphocyte-like cells?

Accepted Answer

Small cell carcinoma

Question 17

A swimmer hyperventilates before diving. What is the physiological risk associated with this practice?

Accepted Answer

Dangerous drop in $\mathrm{P_{O_2}}$ due to delayed urge to breathe, risking hypoxemia.

Question 18

Which of the following is a feature of 'blue bloaters' in COPD?

Accepted Answer

Cyanosis due to hypoxia, resulting in bluish skin color

Question 19

Which of the following mechanisms is responsible for the abrupt increase in ventilation at the onset of exercise?

Accepted Answer

Neural factors including psychological anticipation, cortical motor activation, and proprioceptor input

Chapter 21 - Respiratory System pt. C

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