Pulmonary System Pharynx • The pharynx is a cone-shaped passageway leading from the oral and nasal cavities in the head, to the esophagus and larynx. Thick fibers of muscle and connective tissue attach the pharynx to the base of the skull and surrounding structures. • Consists of 3 main divisions: nasopharynx (upper), oropharynx (behind the oral cavity), laryngopharynx (part of the throat that connects to the esophagus). • Its chamber serves both parts of the respiratory and digestive system. Both systems have entrances to the pharynx, but they are separated from each other by the soft palate. During exercise or during respiratory distress, the mouth can be used as an additional opening of the respiratory system and then the oropharynx also becomes an air-way. • The walls of the pharynx contain striated muscle. During swallowing, the soft palate is raised which divides the pharynx into dorsal and ventral sections. The circular muscles form constrictions that help push food to the esophagus and prevent air from being swallowed, while the longitudinal fibers lift the walls of the pharynx during swallowing. • Pharyngitis illness can be caused by bacteria, viruses, mycoplasmas, fungi, and parasites. Infection by streptococcus bacteria may be a complication arising from a common cold. Larynx • Larynx aka “the voice box” is a hollow, tubular structure connected to the top of the windpipe (trachea); air passes through the larynx on its way to the lungs. The voice box is located on the front of the neck and it holds the vocal cords. • The larynx also produces vocal sounds and prevents the passage of food and other foreign particles into the lower respiratory tracts. • Laryngitis, or inflammation of the larynx, is probably the most common problem with the larynx and voice (the most common are misuse or overuse of the voice and irritation by smoke, dust, or other airborne irritants). Epiglottis • The epiglottis is a cartilaginous flap that extends in front and above the laryngeal inlet, or more specifically the glottis. • The function of the epiglottis is to close the laryngeal inlet during swallowing and so to prevent aspiration of food and liquid into the lungs. • It is located in the larynx and attached to the thyroid cartilage and hyoid bone. Its movements are regulated by the passive pressure from the tongue as it pushes the food down the pharynx, as well as by the contractions of the aryepiglottic muscle. • Epiglottitis is a potentially life-threatening condition that occurs when the epiglottis swells, blocking the flow of air into your lungs. Several factors can cause the epiglottis to swell — burns from hot liquids, direct injury to your throat and various infections. • Vocal cords Vocal cords aka “vocal folds” are folds of tissue located in the larynx (voice box) that have three important functions: • To protect the airway from choking on material in the throat • To regulate the flow of air into our lungs • The production of sounds used for speech. • The front two-thirds of the vocal fold is made up of muscle covered by a thin layer called mucosa. The back one-third is made up of cartilage called the vocal process which is also covered by mucosa. • When we speak muscles in the larynx bring the vocal cords together. As the air rushes from our lungs out through the larynx, the from portion of the vocal cords vibrate, producing a sound. The upper portion of our throat then modifies this sound to produce speech. • When we breathe, one pair of muscles spreads the vocal folds apart so that air can easily enter into the lungs. • Vocal cord nodules; are small, hard, callus-like growths caused by vocal abuse. They occur in pairs, with one nodule on each vocal cord at the site of greatest irritation. They sometimes are called singer's, screamer's or teacher's nodules. Lobes of the lung • The lungs are one of the most important organs present in the body. These are the organs of the respiratory system that are responsible for helping us breathe. The lungs are divided into the right lung and left lung. The right lung has three lobes, whereas the left lung has only two lobes. However, all the lobes help in the exchange of gases and aid breathing. • The right lung has three lung lobes: • Superior lobes • Middle lobes • Inferior lobes • The left lung is divided into two lobes: • Superior lobe • Inferior lobe • Lung cancer is the leading cause of cancer deaths worldwide. People who smoke have the greatest risk of lung cancer, though lung cancer can also occur in people who have never smoked. Tracheal/Bronchial Tree • Trachea is the "breathing tube" of the pulmonary system. It is a muscular tube covered with rings of cartilage. The trachea breaks off into two bronchi which resesmble "branches". • Carina is the visual branch point between the trachea and the bronchi • L and R main stem bronchi • All these direct flow in and out of the lungs Alveoli • The alveoli are sacs that have very thin membranes to facilitate gas exchange with the capillaries • Resembles a grape-like structure • Involved with oxygen and carbon dioxide exchange to the blood • " Not to be confused with ravioli" Capillary membrane • Oxygen diffuses from the alveoli into pulmonary capillaries, while carbon dioxide diffuses from the blood into the alveoli. • Oxygen moves from alveoli to the blood by diffusion through the capillary membranes https://commons.wikimedi a.org/wiki/File:Alveoli.svg# filehistory Henry's Law of Diffusion • When a gas is in contact with the surface of a liquid, the amount of the gas which will go into solution is proportional to the partial pressure of that gas. Guimaraes, E., Kirsch, J. R., Davis, M., & Woodworth, G. (2019). The anesthesia technologist's manual. Philadelphia: Wolters Kluwer. Gas Transport • Oxygen is transported in the blood in two ways: A small amount of O2 (1.5 percent) is carried in the plasma as a dissolved gas. Most oxygen (98.5 percent) carried in the blood is bound to the protein hemoglobin in red blood cells. • Oxygen is delivered to the tissues and deoxygenated blood (loaded with CO2) leaves the tissues of the body and flows back to the heart where it pumped to the lungs via the pulmonary arteries. • Gases move down their pressure gradients at the lungs and tissue capillaries. Thoracic Rib Cage • forms the thorax (chest) portion of the body. • Sternum: is a long flat bone • located centrally on the chest. Protect the lungs, heart and other vital organs • xiphoid process: the cartilaginous section at the lower end of the sternum, which is not attached to any ribs, and gradually ossifies during adult life. Diaphragm • Thin skeletal muscle • Sits at the lower part of the chest and acts as a boundary between the abdomen and the chest. • When one inhales it expands and relaxes • Complication of the diaphragm include chronic thoracotomy pain, pleural effusion, pulmonary embolism and atelectacis Lung Volume • It refers to the volume of gas in the lungs at a given time during the respiratory cycle. • Lung capacities are derived from a summation of different lung volumes. • The average total lung capacity of an adult human male is about 6 litres of air. • Lung volumes measurement is an integral part of pulmonary function test.