Respiratory Physiology Flashcards
How many generation of airways do you find in the respiratory system?
23
How many alveoli are present in the respiratory system?
500 million
What is the sympathetic effect on smooth muscle of the airways?
Smooth Muscle Relaxation (Beta-2)
What is the parasympathetic effect on smooth muscle of the airways?
Smooth Muscle Contraction (Muscarinic)
No gas exchange; Transports gas to the lungs; Nose to Terminal Bronchioles
Conducting Zone
Areas of gas exchange; Respiratory Bronchioles, Alveolar Ducts, Alveolar sacs
Respiratory Zone
96-98% of surface area; For gas exchange
Type I Pneumocyte
2-4% of surface area; For surfactant production
Type II Pneumocyte
Keep alveoli free of dust and debris
Alveolar macrophages
Produce mucus
Goblet cells, Submucosal Glands
May play a re in epithelial regeneration after injury by secreting protective GAGs
Clara Cells (Club Cells)
Carries deoxygenated blood to the lungs
Pulmonary Circulation
Carries oxygenation blood to the lungs
Bronchial Circulation
4 Basic Lung volumes
Inspiratory Reserve Volume (IRV)Tidal Volume (TV)Expiratory Reserve Volume (ERV)Residual Volume (RV)
What is a Lung Capacity?
Sum of two or more lung volumes (Inspiratory Capacity (IC), Functional Residual Capacity (FRC), Vital Capacity (VC), Total Lung Capacity (TLC)
How do you measure lung Volumes and Capacities?
Spirometry
Only Lung Volume that cannot be measured directly by spirometry?
Residual Volume, FRC, TLC
Amount of Air inspired/expired during quiet breathing?
Tidal Volume 500ml: 150ml in the conducting zone, 350ml in the respiratory zone
Differences in terms of Lung Volumes and Capacities among sexes?
20-25% lower in females
Maintains oxygenation in between breaths?
Residual Volume
Equilibrium or Resting Volume of the Lungs?
Functional Residual Capacity (FRC) (marker of Lung function)
Factors that increases Vital Capacity (VC)?
Body size, Male gender, Physical Conditioning, youth
Anatomic Dead Space + Alveolar Dead Space; Total volume of the lungs that does NOT participate in gas exchange
Physiologic Dead Space
Air in the conducting zone
Anatomic Dead Space (150ml)
Air in the alveoli not participating in gas exchange due to V/Q mismatch (0ml)
Alveolar Dead Space
Volume of air moved into and out of the lungs per unit time
Ventilation Rate
Total rate of air movement in/out of the lungs
Minute Ventilation
Minute ventilation corrected for physiologic dead space
Alveolar Ventilation
What happens to the FEV1 and FVC in patients with obstructive and restrictive lung diseases?
Decreased
What is the FEV1/FVC ratio of a healthy person?
0.8
What happens to the FEV1/FVC ratio in patients with obstructive and restrictive lung diseases respectively?
Obstructive: DecreasedRestrictive: Normal to Increased
Normal Inspiration
Active (Diaphragm)
Forced Inspiration
External Intercostals
Normal Expiration
Passive
Forced Expiration
Internal Intercostals
Change in volume for a given change in pressure?
Compliance
What do you call the difference between compliance curves during inspiration and expiration of an air-filled lung?
Hysteresis
What is the basis for hysteresis?
Surface tension at air-liquid interface
Loss of elastic fiber, increased compliance, decreased elasticity, increased FRC, barrel-shaped chest
Emphysema
Stiffening of lung tissue, decreased compliance, increased elasticity, decreased FRC
Fibrosis
Force caused by water molecules at the air-liquid interface that tends to minimize surface area
Surface Tension
Active Component
DPPC (main component: water)
Mechanism of DPPC reducing surface tension
Amphiphatic Nature (hydrophobic and hydrophilic)
Effect of surfactant on lung compliance
Increases
Start of and maturation of surfactant levels respectively
24th and 35th week
Test, Treatment for RDS?
Amniotic L-S Ratio; Steroids; Surfactant
Formula for Airflow
Ohm’s Law
Formula for Airway Resistance?
Poiseuille’s Law
Factors in airway resistance?
Sympathetic: decreasesParasympathetic: increasesLung volume: decreasesViscosity of inspired air: increases
Formula for transpulmonary pressure
Alveolar pressure-Intrapleural pressure
If transpulmonary pressure is positive
Lungs expand
If transpulmonary pressure is negative
Lungs collapse
Transpulmonary pressure in healthy persons
Positive (lungs always open)