Respiratory Cycle And Homeostasis

The respiratory system provides life giving oxygen to cells through inspiration of air; at the same time, it removes carbon dioxide waste from cells through expiration, which can be lethal if not ventilated properly. This process is called pulmonary ventilation and is facilitated by three major components of the respiratory system: airways, lungs, and muscles; all of which play a vital role in the respiratory cycle and homeostasis. The respiratory cycle begins in the airways and during inhalation, the mouth, nose, pharynx, larynx, trachea, bronchi, and bronchioles assist in carrying oxygen rich air between the bodies exterior to the lungs, and ventilates carbon dioxide in reverse. The nose and nasal cavity form the respiratory tract through which air moves. The nasal cavity is lined with hairs and a mucus membrane, which warm, moisten, and filter air by trapping external contaminants before they can reach the lungs. The mouth is the
However, this magic is not possible without the assistance of the bronchi and bronchioles, which are the last structures air passes through before reaching the lungs. The air from the trachea splits into the left and right bronchi, which funnel into each lung before branching again into smaller secondary bronchi that deposit air into the lobes of the lungs (2 lobes in the left lung and 3 in the right lung). The secondary bronchi split again into smaller tertiary bronchi within each lobe and transform again into millions of tiny terminal bronchioles that spread throughout the lungs. These terminal bronchioles terminate at alveolar sacs, where air is conducted into roughly 30 million individual alveoli that are encased by pulmonary capillaries. The alveoli are lined with thin simple squamous epithelium that allows air entering the alveoli to exchange oxygen and carbon dioxide with the blood passing through these capillaries. This process is known as external