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Type I cells (alveolar) Wall of alveoli, single layer of simple squamous epithelium
Type II cells (alveolar) Secrete surfactant
Alveolar Macrophage immune defense in the alveoli
gas exchange Blood in capillaries meets air in alveoli at respiratory membrane where
simple diffusion occurs
Thoracic Cavity rib cage, intercostals, diaphragm, pleura, sternum, thoracic vertebrae
Intercostal muscles Increase volume of chest cavity
Diaphragm Muscle, Bell shaped higher center. Pulls downward and makes thoracic cavity
taller.
, SLCC: Human Physiology exam 4 Questions
With Complete Solutions
visceral pleura portion of pleural sac connected to the lung tissue
Parietal Pleura Portion of pleural sac connected to thoracic wall
inter-pleural space fluid filled potential space between pleural membranes.
Functional Residual Capacity (FRC) Volume of air in lungs between breaths. All forces
acting across lungs and chest wall are balanced, and system is in steady state.
forces for pulmonary ventilation air flow driven by pressure gradients.
4 types of pressure:
Atmospheric Pressure
Intra-alveolar pressure
intra-pleural pressure
transpulmonary pressure
, SLCC: Human Physiology exam 4 Questions
With Complete Solutions
atmospheric pressure (P_atm) pressure of outside air. 760 mmHg at sea level. atmospheric
pressure decreases as elevation increases. All other lung pressures are relative to atmospheric
pressure.
intra-alveolar pressure (P_alv) pressure of air in alveoli. At rest (FRC) pressure is 0
mmHg. when pressure is less/greater than atmospheric pressure inspiration/expiration occurs
respectively.
intra-pleural pressure (P_ip) pressure inside the pleural space
transpulmonary pressure (P_alv-P_ip) difference between intra-pleural pressure and intra-
alveolar pressure
Boyles Law For any gas, pressure is inversely related to the volume of container.
Ideal Gas Law PV=nRT & P=nRT/V
P=pressure