AN SC 310 - 19
Card Set Information
AN SC 310 - 19
AN SC 310
Lecture 19 - The Respiratory System: Pulmonary Ventilation
What is external respiration?
exchange btwn lungs and blood
transportation in blood
exchange btwn blood and body tissues
What are the upper airways?
What are the components of the respiratory tract?
What are the structures of the conducting zone?
Secondary bronchi (R has 3, L has 2)
Tertiary bronchi (20-23 orders of branching)
Bronchioles (less than 1mm diameter)
What are the functions of the conducting zone?
Air passageway (150 mL volume = dead space volume)
Increase air temp to body temp
What is the epithelium of the conducting zone comprised of?
Goblet cells - secrete mucus
Ciliated cells - move particles toward mouth
What are the structures of the respiratory zone?
What are the functions of the respiratory zone?
Exchange of gases btwn air and blood
Mechanism is by diffusion
What is the epithelium of the respiratory zone comprised of?
Respiratory membrane - epithelial cells of alveoli, endothelial cells of capillary
What are some properties of alveoli?
Site of gas exchange
300 million alveoli/lung
Rich blood supply
What are 3 types of alveolar cells?
Type I alveolar cells - make up wall of alveoli
Type II alveolar cells - secrete surfactant
What is the job of the respiratory membrane?
Barrier for diffusion - type I cells + basement membrane, capillary endothelial cells + basement membrane
What are the structures of the thoracic cavity?
Chest wall - rib cage, sternum, thoracic vertebrae, muscles
Pluera - membrane lining of lungs and chest wall
What is the volume of the interplueral space?
What is the role of pressure in the pulmonary ventilation?
Air moves from high to low pressure
Inspiration - pressure in lungs less than atmosphere
Expiration - pressure in lungs greater than atmosphere
How does intra-alveolar pressure vary?
Inspiration = negative (less than atmospheric)
Expiration = positive (more than atmospheric)
How does intrapleural pressure compare to atmospheric?
Always negative under normal conditions
Always less than Patm
Varies w/ phase of respiration (at rest = -4 mm Hg)
What the negative pressure in pleural sacs caused by?
Elasticity in lungs and chest wall
Opposition of lungs and chest wall pulls on intrapleural space
Surface tension of intrapleural fluid holds wall and lungs together
What is transpulmonary pressure?
Palv - Pip
Distending pressure across the lung wall
What is the equation for air flow?
What creates/changes pressure gradients in lungs?
What is boyle's law?
Pressure is inversely related to volume
What factors determine intra-alveolar pressure?
Quantity of air in alveoli
Volume of alveoli
What muscles are involved in inspiration?
What muscles are involved in expiratory muscles?
Generally, expiraiton is passive (unless exercising)