We cannot teach people anything; we can only help them discover it within themselves. Galileo Galilei. Introduction to Respiratory system Structure and Function of the Respiratory System. Learning objectives. Physioanatomy of the upper and lower respiratory tract Weibel model
Two major factors determine the speed at which gas flows into the airways for a given pressure change:
Stimulation of efferent vagal fibers, either directly or reflexively (smoke, dust, cold air, or other irritants )
Agents such as histamine, acetylcholine, thromboxane A2, prostaglandin F2, and leukotrienesreleased by airway cells in response to various triggers, such as allergens and viral infections
The bronchial circulation arises from the aorta and contains 1% to 2% of cardiac output
They nourish the walls of the bronchi, bronchioles, blood vessels, and nerves, and they perfuse the lymph nodes and most of the visceral pleura
The cilia are bathed in a periciliary fluid .
On top of the periciliary layer and the beating cilia rests a mucus layer, a complex mixture of proteins and polysaccharides secreted from specialized cells, glands, or both in the conducting airway.
This combination allows for the trapping of foreign particles (in the mucus) and their transport out of the airway (powered by ciliary beat)