RESPIRATORY SYSTEM:
 
 
 
I. RESPIRATORY SYSTEM FUNCTION:
 
A. Why a respiratory system?
 
B. Gas transport: Oxygen in and Carbon Dioxide out
 
II. VENTILATION: Structure and Function
 
A. Gas conduction:
Upper respiratory tract: Gas humidification, filtration, and warming
Conducting airways: Gas distribution to respiratory zone
 
B. Negative Pressure Breathing:
 
 
III. DIFFUSION: Structure and Function
 
A. Diffusion: Basic concepts
 
 
 
B. The respiratory zone:
 
Respiratory bronchioles, alveolar ducts and alveoli.
The zone is designed to maximize efficient gas exchange by diffusion:
 
Alveolar blood-gas barrier:
 
 
C. Pulmonary blood flow:
 
All of cardiac output (+/-5%) passes through the respiratory zone.
. Pulmonary arteries carry blood from the right heart (de-oxygenated).
Pulmonary arteries distribute blood to the pulmonary capillary system to maximize erythrocyte exposure to alveolar gas tensions.
The churning/pumping action of the heart aids in gas diffusion in the respiratory zone.
The bronchial vessels arise from the aorta and carry nutrient blood to the airways.
Thus the lung is efficiently designed to conduct and distribute gas to a very large, thin diffusion membrane with good blood supply.
 
IV. NON-RESPIRATORY FUNCTION OF THE LUNG:
 
A. Basic concepts:
Maintenance and defense:
Filtering:
The lung is ideally designed to filter the bloodstream of particulate matter (clots, bacteria, etc.) before passing that blood on to the body.