NU 545 (Advanced Pathophysiology) Unit 5, Pulmonary & Renal/Kidney Pathophysiology Verified Questions & Correct Answers

NU 545 (Advanced Pathophysiology) Unit 5, Pulmonary &
Renal/Kidney Pathophysiology Verified Questions &
Correct Answers


Part 1: Pulmonary Structure, Ventilation, and Gas Exchange
1. Which respiratory cells are responsible for providing the primary structural
framework of the alveoli?
 A) Type II alveolar cells
 B) Type I alveolar cells
 C) Alveolar macrophages
 D) Goblet cells
 Type I alveolar cells are thin, flat epithelial cells that cover about 90–95% of the
alveolar surface, providing the primary structure for gas exchange. Type II cells
produce surfactant.
2. What is the primary function of surfactant in the lung alveoli?
 A) To facilitate the transport of carbon dioxide.
 B) To lower surface tension at end-expiration, preventing alveolar collapse
 C) To filter out microscopic pathogens.
 D) To increase the elastic recoil of the chest wall.
 Surfactant is a lipoprotein that coats the inner surface of the alveolus, lowering
surface tension to allow expansion during inspiration and prevent collapse
(atelectasis) during expiration.
3. At how many weeks of gestation is surfactant typically produced and secreted into
the fetal airways?
 A) Produced at 12 weeks; secreted at 20 weeks
 B) Produced at 20–24 weeks; secreted by 30 weeks

,  C) Produced at 28 weeks; secreted at 36 weeks
 D) Produced at 32 weeks; secreted at 38 weeks
 Type II alveolar cells begin producing surfactant around 20–24 weeks of gestation,
and it is secreted into the airways by week 30, which is critical for neonatal viability.
4. Which physical principle states that the pressure ($P$) required to inflate a sphere
is equal to two times the surface tension ($T$) divided by its radius ($r$)?
 A) Boyle's Law
 B) Law of Laplace
 C) Henry's Law
 D) Dalton's Law
 The Law of Laplace is expressed as $P = 2T/r$. It explains why smaller alveoli
(smaller radius) require more pressure to stay open without surfactant.
5. What process describes the physical mechanical movement of gas or air into and
out of the lungs?
 A) Respiration
 B) Diffusion
 C) Ventilation
 D) Perfusion
 Ventilation is the mechanical movement of air, whereas respiration refers to the
cellular/molecular exchange of gases ($O_2$ and $CO_2$).
6. Where does the actual exchange of carbon dioxide for oxygen take place at the
capillary level?
 A) In the segmental bronchi
 B) In the acinus (alveolocapillary membrane)
 C) In the trachea
 D) In the major bronchioles

,  The acinus—composed of respiratory bronchioles, alveolar ducts, and alveoli—is
the functional respiratory unit where gas exchange occurs across the thin
alveolocapillary membrane.
7. What is the definition of tidal volume ($V_T$)?
 A) The total amount of air remaining in the lungs after a forced exhalation.
 B) The volume of air inspired or expired with each normal, resting breath
 C) The maximum amount of air that can be inhaled after a normal inspiration.
 D) The volume of air that never reaches the alveoli.
 Tidal volume is the amount of air shifted in and out of the respiratory tract during
quiet breathing, largely determined by height and ideal weight.
8. How does the pulmonary circulation differ from the bronchial circulation?
 A) Pulmonary circulation participates in gas exchange; bronchial circulation
supplies oxygenated blood to the conducting airways and does not participate
in gas exchange
 B) Bronchial circulation originates from the right ventricle.
 C) Pulmonary circulation arises directly from the thoracic aorta.
 D) Bronchial circulation is responsible for transporting oxygen to the left atrium.
 Pulmonary circulation is a low-pressure system designed for gas exchange.
Bronchial circulation is a high-pressure system arising from the systemic trunk
(thoracic aorta) that perfuses the structures of the lung itself.
9. What occurs in pulmonary blood vessels when alveolar oxygen levels drop below
60 mmHg?
 A) Vasodilation
 B) Hypoxic pulmonary vasoconstriction
 C) No change in vessel diameter
 D) Complete occlusion by platelet aggregation
 Unlike systemic vessels which dilate in response to hypoxia, pulmonary vessels
constrict (hypoxic pulmonary vasoconstriction) to shunt blood away from poorly
ventilated alveoli to well-ventilated areas.

, 10. Which brain stem center acts as the primary pacemaker for breathing under
resting conditions?
 A) Pneumotaxic center
 B) Apneustic center
 C) Dorsal respiratory group (DRG) in the medulla
 D) Ventral respiratory group (VRG) in the medulla
 The DRG contains inspiratory neurons that establish the basic rhythm of breathing.
The VRG becomes active when increased or forced expiratory effort is required.
11. Which receptors monitor the pH, $PaCO_2$, and $PaO_2$ of arterial blood?
 A) Central and peripheral chemoreceptors
 B) Stretch receptors
 C) J-receptors
 D) Irritant receptors
 Central chemoreceptors in the medulla monitor pH and $CO_2$ levels in the CSF,
while peripheral chemoreceptors in the carotid and aortic bodies primarily monitor
arterial $PaO_2$ levels.
12. What is the definition of "pulmonary compliance"?
 A) The force required to keep the airway open.
 B) The measure of lung and chest wall distensibility (ease of stretching)
 C) The elastic recoil force of the lung tissue.
 D) The resistance encountered by air flowing through the trachea.
 Compliance represents how easily the lungs expand ($C = \Delta V / \Delta P$). It is
the reciprocal of elasticity (stiffness).
13. Which of the following normal age-related alterations occurs in the pulmonary
system?
 A) Increased elastic recoil
 B) Decreased flow resistance