Question 1

During normal inspiration, which of the following best describes the changes in thoracic volume and intrapulmonary pressure, and how do these changes drive airflow?

Accepted Answer

Thoracic volume increases, intrapulmonary pressure decreases, and air moves into the lungs.

Question 2

Which muscles are primarily responsible for active (forced) expiration, such as during vigorous exercise?

Accepted Answer

Internal intercostals and abdominal muscles

Question 3

Lung compliance is determined by which two main factors?

Accepted Answer

Elasticity of lung tissue and surface tension of alveolar fluid

Question 4

A premature infant is experiencing respiratory distress due to a lack of surfactant. What is the primary physiological consequence of this deficiency?

Accepted Answer

Increased surface tension in the alveoli, making it harder to inflate the lungs

Question 5

Given the following partial pressures: $pO_2$ in alveoli = 104 mmHg, $pO_2$ in venous blood = 40 mmHg, in which direction will oxygen diffuse?

Accepted Answer

From alveoli into venous blood

Question 6

Which of the following best explains why carbon dioxide ($CO_2$) moves from the tissues into the capillaries?

Accepted Answer

$pCO_2$ is higher in the tissues than in the capillaries

Question 7

Hemoglobin can bind up to how many molecules of oxygen ($O_2$)?

Accepted Answer

4

Question 8

Which of the following conditions will promote the release of oxygen from hemoglobin in systemic tissues?

Accepted Answer

High $pCO_2$, low pH, high temperature

Question 9

During exercise, which of the following changes in the blood will most likely increase the amount of oxygen released by hemoglobin to the tissues?

Accepted Answer

Increase in temperature

Question 10

Which of the following equations correctly represents the reaction catalyzed by carbonic anhydrase in red blood cells?

Accepted Answer

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

Question 11

What is the chloride shift, and why is it important in red blood cells?

Accepted Answer

It is the movement of $Cl^-$ ions into red blood cells as $HCO_3^-$ ions move out, maintaining electrical neutrality.

Question 12

Which of the following best describes the difference between fetal and adult hemoglobin?

Accepted Answer

Fetal hemoglobin has a higher affinity for oxygen than adult hemoglobin.

Question 13

Which part of the brain contains the primary regulatory centers for respiration?

Accepted Answer

Medulla oblongata

Question 14

A person holds their breath for as long as possible. What is the primary stimulus that eventually forces them to breathe?

Accepted Answer

Increased $pCO_2$ in the blood

Question 15

Which of the following best describes the Hering-Breuer reflex?

Accepted Answer

It prevents over-inflation of the lungs by inhibiting inspiration when the lungs are stretched.

Question 16

Which of the following is NOT a way that carbon dioxide ($CO_2$) is transported in the blood?

Accepted Answer

Bound to plasma albumin

Question 17

If a patient is experiencing hypercapnia (elevated $CO_2$ levels), what effect will this have on ventilation?

Accepted Answer

Ventilation will increase to expel more $CO_2$.

Question 18

Which of the following best explains the role of the pneumotaxic area in the regulation of breathing?

Accepted Answer

It inhibits the inspiratory center to limit inspiration and regulate respiratory rate.

Question 19

A patient with metabolic acidosis is likely to experience which of the following respiratory responses?

Accepted Answer

Increased ventilation to expel $CO_2$

Question 20

Which of the following best describes the movement of $HCO_3^-$ and $H^+$ after carbonic anhydrase catalyzes the reaction in red blood cells?

Accepted Answer

$HCO_3^-$ diffuses out of the RBC into plasma, $H^+$ binds to hemoglobin

Respiratory System: Ventilation, Gas Exchange, and Regulation – Study Guide

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