Module 05 Written Assignment - Respiration and Urinary Systems
1. Atmospheric air takes a specific pathway from the external environment to our internal lungs. Describe this pathway starting with external nares to the alveoli. What role does the trachea and surfactant play within the respiratory system?
Air enters the respiratory system through the nostrils (external nares) where the air is being filtrated, warmed, and humidified. Air is then passed through the pharynx which is also called the throat. It also shares its chamber with the esophagus. From the throat, it passes through an open glottis allowing the air to enter the larynx (voice box) within the larynx, you have an elastic mechanism called the epiglottis that protects the trachea from food and liquid entering the respiratory tract.
Air leaving the larynx passes into the trachea. The trachea is a sturdy, flexible tube that does double duty. The trachea protects the airway from over expansion and collapsing due to respiratory pressure changes and it consists of a series of c-shape rings which makes it stable and flexible. Since the esophagus runs parallel posteriorly to the trachea, the open portions of the trachea’s C-shaped rings face posterior toward the esophagus that allows a bending movement of the trachea and easily allows food to pass through the esophagus. Air from the trachea passes through the larger right and smaller left bronchi that descends into the right and left lungs. In the lungs, the bronchi re-branches into the secondly bronchi that eventually re-branches into tiny bronchioles. Air movement into the tiny bronchioles finally terminates in a cluster of alveoli, where the gases are exchanged. (pp. 504-511)
Surfactant is an important oily substance secreted by septal cells that covers the thin layer of water coating on the alveolar surface. Water provides surface tension; therefore, surfactant main purpose is to decrease surface tension. Surfactant promotes...