Updated: 8/10/2020

Airflow, Pressure, and Resistance

0%
Topic
Review Topic
0
0
N/A
N/A
Questions
2
0
0
100%
0%
Evidence
1
0
0
Topic
  • Overview
    • Airflow, Pressure, and Resistance
      • Q = ΔP / R
        • airflow is directly proportional to pressure difference between mouth/nose (atmospheric) and alveoli
        • airflow is inversely proportional to airway resistance
    • Airway Resistance
      • R = 8ηl / Ï€r4
        • η = viscosity of inspired air
        • l = length of airway
        • r = radius of airway
      • total resistance depends on the aggregate cross-sectional area of a zone
        • highest in the bronchi between the 4th and 8th generations of branching
    • Changes in Airway Resistance
      • changes in airway diameter provide major mechanism for altering airway resistance and airflow
      • Autonomic Nervous System
        • sympathetic stimulation
          • bronchial smooth muscle is innervated by sympathetic adrenergic nerve fibers
          • sympathetic stimulation → (+) β2 receptors → relaxation → ↑ airway diameter, ↓ resistance to airflow
          • β2 agonists (e.g., epinephrine, isoproterenol, albuterol) relax bronchial smooth muscle and dilate airway in treatment of asthma
        • parasympathetic stimulation
          • bronchial smooth muscle is innervated by parasympathetic cholinergic nerve fibers
          • parasympathetic stimulation → (+) muscarinic receptors → constriction → ↓ airway diameter, ↑ resistance to airflow
    • Pulmonary Vascular Resistance (PVR)
      • PVR = [P(pulmonary artery) - P(left atrium)] / cardiac output
        • P(pulmonary artery) is pressure in pulmonary artery
        • P(left atrium) is pulmonary capillary wedge pressure

Please rate this review topic.

You have never rated this topic.

Thank you. You can rate this topic again in 12 months.

Flashcards (0)
Cards
1 of 0
Questions (2)
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Evidence (1)
VIDEOS & PODCASTS (1)
EXPERT COMMENTS (3)
Private Note