LPN exams respiratory practice questions set 12

Correct answer:

Airway resistance (R) follows Poiseuille's law (R ∝ 1/r^4), but total resistance depends on cross-sectional area. Later generations (bronchioles) have smaller radii, yet their vast number increases total area (e.g., ~300 cm² vs. trachea's 3-4 cm²), reducing overall R most resistance is in larger airways (trachea, bronchi), where flow is turbulent, making this false. Normally, ~80% of R is in large airways, dropping in smaller ones due to laminar flow and area. Increased R (e.g., asthma) lowers FEV1/FVC (<70%), as FEV1 falls more, a true obstructive sign. Loss of elasticity (emphysema) and bronchoconstriction (asthma) raise R by collapsing or narrowing airways, also true. The false idea of increasing R in later generations misinterprets branching dynamics, where resistance peaks proximally, not distally, aligning with physiological airflow distribution.

Correct answer:

cholinergic discharge (acetylcholine, parasympathetic) causes bronchoconstriction, not bronchodilation. Choice B is true; β₂-agonists (e.g., albuterol) activate adrenergic receptors, relaxing bronchial smooth muscle. ' β₂-agonists increase mucus secretion, a secondary effect to dilation. Choice D is true; vasoactive intestinal peptide (VIP) promotes bronchodilation by relaxing smooth muscle. Cholinergic stimulation, via vagus nerve, contracts bronchioles, increasing resistance opposite to bronchodilation's airway widening. This reflects autonomic balance: parasympathetic constricts, sympathetic (β₂) dilates. A's reversal of this physiology misrepresents airway control, where bronchodilation aids airflow (e.g., asthma treatment), while cholinergic effects narrow airways for rest or protection. Thus, A is the incorrect pairing.

Correct answer:

The correct answer is B: Decreased diffusion capacity for oxygen. With age, respiratory dead space increases, leading to a mismatch between ventilation and perfusion in the lungs. This results in a decrease in the ability of the lungs to effectively transfer oxygen into the bloodstream, reducing the diffusion capacity for oxygen. This physiological change can lead to decreased oxygenation of tissues and organs. Summary: A: Increased diffusion of gases - Incorrect. Increased dead space does not enhance gas diffusion; instead, it impairs gas exchange. C: Decreased shunting of blood - Incorrect. Shunting refers to blood bypassing oxygenation in the lungs, which is not directly affected by dead space. D: Increased ventilation - Incorrect. While dead space may lead to increased ventilation efforts, it does not directly improve oxygen diffusion capacity.

Correct answer:

Residual volume (RV) is the air left in the lungs after maximal expiration (~1-1.5 L), preventing collapse and measurable only indirectly (e.g., helium dilution). It's not just after tidal expiration that's FRC (~2.5-3 L), including RV plus ERV, making that false. In COPD, RV increases (e.g., to 2-3 L) due to air trapping from obstructed airways and lost elasticity, not decreases. In pulmonary fibrosis, a restrictive disease, RV decreases (e.g., to <1 L) as stiff lungs limit all volumes, including residual air, making this correct. RV doesn't stay constant lifelong aging and disease alter it but in health, it's relatively stable, though this isn't the strongest fit. Fibrosis's reduction reflects restricted lung expansion, contrasting with obstructive hyperinflation, making it the accurate statement amid options misaligned with RV's physiological behavior.

Correct answer:

Residual volume (RV) is the air left in the lungs after maximal expiration (~1-1.5 L), preventing collapse and measurable only indirectly (e.g., helium dilution). It's not just after tidal expiration that's FRC (~2.5-3 L), including RV plus ERV, making that false. In COPD, RV increases (e.g., to 2-3 L) due to air trapping from obstructed airways and lost elasticity, not decreases. In pulmonary fibrosis, a restrictive disease, RV decreases (e.g., to <1 L) as stiff lungs limit all volumes, including residual air, making this correct. RV doesn't stay constant lifelong aging and disease alter it but in health, it's relatively stable, though this isn't the strongest fit. Fibrosis's reduction reflects restricted lung expansion, contrasting with obstructive hyperinflation, making it the accurate statement amid options misaligned with RV's physiological behavior.

Correct answer:

Beclomethasone (Beclovent), an inhaled corticosteroid, reduces inflammation in COPD airways, easing breathing by decreasing mucosal swelling and mucus production, which obstruct airflow. It doesn't prevent airway dilation (A) that's counterproductive; it enhances beta-agonist responsiveness, dilating airways indirectly. While it suppresses immunity (C), this isn't the primary therapeutic goal reducing inflammation is. It doesn't decrease responsiveness to bronchodilators (D); it may enhance it. The exact mechanism is unclear, but its anti-inflammatory action targets chronic airway irritation, a hallmark of COPD, distinct from bronchodilators' immediate relief. This explanation aligns with patient education, emphasizing improved airflow over side effects, critical for adherence and understanding treatment's role in managing COPD's progressive obstruction.

Correct answer:

Choice C is false. Surfactant, produced by Type II pneumocytes (choice E), reduces surface tension (choice B) and stabilizes alveoli (choice A) by equalizing pressure across sizes, preventing collapse. It also lowers alveolar pressure, reducing fluid transudation into capillaries (choice D). However, per Laplace's law (P = 2T/r), surface tension (T) drives pressure (P) inversely with radius (r). Without surfactant, smaller alveoli would have higher pressure and collapse into larger ones (higher T, lower r). Surfactant lowers T more in smaller alveoli, equalizing pressure, not making larger alveoli's T lower than smaller ones' it balances them. Choice C misstates this; larger alveoli naturally have lower pressure due to larger r, but T isn't inherently lower without surfactant's effect. Thus, C contradicts surfactant's role, making it the false statement.

Correct answer:

The correct answer is B: Non-rebreather mask. This device provides the highest concentration of oxygen among the choices, around 80-100%. In a client with difficulty breathing and low oxygen saturation, a high concentration of oxygen is crucial to quickly reverse hypoxemia. The non-rebreather mask ensures that the client is receiving the maximum amount of oxygen with each breath, improving oxygenation rapidly. A: Simple mask delivers a lower concentration of oxygen and would not be sufficient for a client in distress. C: Face tent does not provide a high concentration of oxygen and may not be effective in quickly reversing hypoxemia. D: Nasal cannula delivers a lower concentration of oxygen compared to the non-rebreather mask and may not be enough to reverse manifestations in a client with significant difficulty breathing and low oxygen saturation.

Correct answer:

Beclomethasone (Beclovent), an inhaled corticosteroid, reduces inflammation in COPD airways, easing breathing by decreasing mucosal swelling and mucus production, which obstruct airflow. It doesn't prevent airway dilation (A) that's counterproductive; it enhances beta-agonist responsiveness, dilating airways indirectly. While it suppresses immunity (C), this isn't the primary therapeutic goal reducing inflammation is. It doesn't decrease responsiveness to bronchodilators (D); it may enhance it. The exact mechanism is unclear, but its anti-inflammatory action targets chronic airway irritation, a hallmark of COPD, distinct from bronchodilators' immediate relief. This explanation aligns with patient education, emphasizing improved airflow over side effects, critical for adherence and understanding treatment's role in managing COPD's progressive obstruction.

Correct answer:

The correct answer is A: pulmonary ventilation. Atmospheric pressure plays a crucial role in pulmonary ventilation by creating a pressure gradient that allows air to flow into and out of the lungs during inhalation and exhalation. When the atmospheric pressure is higher than the pressure inside the lungs, air moves in (inhalation); when the pressure inside the lungs is higher, air moves out (exhalation). Summary of why the other choices are incorrect: B: Production of pulmonary surfactant is not directly influenced by atmospheric pressure. Pulmonary surfactant reduces surface tension in the alveoli to prevent collapse. C: Resistance in the respiratory system is mainly influenced by airway diameter and elasticity of the lungs, not atmospheric pressure. D: Surface tension in the alveoli is affected by pulmonary surfactant, not atmospheric pressure.