Respiratory — Flashcards

Flashcard 221: The sum of the tidal volume plus the inspiratory reserve volume is known as _____

Answer: inspiratory capacity

Flashcard 222: The somatic nervous system utilizes _____ as its neurotransmitter

Answer: acetylcholine

Flashcard 223: _____ ventilation is the total volume of gas that enters the lungs per unit time

Answer: Minute

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

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

Flashcard 225: What is the effect of normal aging on total lung capacity?_____

Answer: No change

Flashcard 226: In response to decreased Pao2 (e.g. high altitude), there is _____ ventilation

Answer: increased

Flashcard 227: Without surfactant, small alveoli are more likely to collapse, which is termed _____

Answer: atelectasis

Flashcard 228: The additional volume that can be expired below tidal volume is the _____

Answer: expiratory reserve volume

Flashcard 229: Obstructive lung diseases are characterized by a(n) _____ residual volume and functional residual capacity

Answer: increased

Flashcard 230: 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.