Respiratory — Flashcards

Flashcard 221: In the muscle stretch reflex, some Ia afferent fibers inhibit _____ muscles (agonist or antagonist) through interneurons causing muscle relaxation

Answer: antagonist

Flashcard 222: What is the effect of decreased gas density (e.g. helium inhalation) on airway resistance? _____

Answer: Decreased resistance

Extra: Helium inhalation (Heliox) is used to decrease airway resistance because helium has a much lower **density** than nitrogen (the main component of room air). In conditions where airflow is **turbulent** (like upper airway obstruction), resistance is proportional to gas density. Note: In **laminar flow**, resistance is proportional to gas **viscosity** (Poiseuille's law). Helium actually has a slightly higher viscosity than air, so its clinical benefit is entirely due to its low density.

Flashcard 223: Obstructive lung diseases are characterized by a(n) _____ residual volume and functional residual capacity

Answer: increased

Flashcard 224: Which type of filament is predominantly involved in movement and cell division? _____

Answer: Microtubules (e.g. cilia, flagella)

Flashcard 225: Which leukotrienes mediate vasoconstriction, bronchospasm, and increased vascular permeability? _____

Answer: Leukotrienes C4, D4, and E4

Flashcard 226: How does Paco2 change in response to exercise?_____

Answer: No change

Flashcard 227: The additional volume that can be expired below tidal volume is the _____

Answer: expiratory reserve volume

Flashcard 228: The additional volume that can be inspired above tidal volume is the _____

Answer: inspiratory reserve volume

Flashcard 229: Obstructive lung diseases are characterized by obstruction of air flow resulting in air _____ in lungs

Answer: trapping

Flashcard 230: The Po2 in humidified tracheal air is normally approximately _____ mmHg

Answer: 150