Respiratory System PDF

The Respiratory System Chapter 22 22.1 – Organs and Structures of the Respiratory System ▪ Conducting zone – route for incoming and outgoing air, remove debris and pathogens, warm and humidify incoming air (nose, pharynx, larynx, trachea, and bronchial tree) 22.1 - Nose ▪ Major entrance and exit for...

The Respiratory System Chapter 22 22.1 – Organs and Structures of the Respiratory System ▪ Conducting zone – route for incoming and outgoing air, remove debris and pathogens, warm and humidify incoming air (nose, pharynx, larynx, trachea, and bronchial tree) 22.1 - Nose ▪ Major entrance and exit for the respiratory system, combination of bone and cartilage, 2 nostrils separated by nasal septum ▪ Nasal conchae – disrupt airflow and force air to bounce along the epithelium to warm and clean it ▪ Air is moved into the pharynx ▪ Sinuses produce mucus and lighten the skull ▪ Cilia beat constantly to push mucus and debris toward the throat to be swallowed 22.1 ▪ Cold air slows cilia resulting in a runny nose due to mucus accumulation ▪ Mucus contains lysozyme enzymes and proteins called defensins which have antibacterial properties 22.1 - Pharynx ▪ Tube continuous with the nasal cavity ▪ Nasopharynx – should be air only, connect to Eustachian tubes ▪ Oropharynx – both food and air ▪ Laryngopharynx – splits into larynx anteriorly and esophagus posteriorly 22.1 - Larynx ▪ Cartilaginous structure connecting the trachea and the pharynx ▪ Formed by thyroid cartilage, epiglottis, and cricoid cartilage ▪ Thyroid cartilage consists of the Adam’s Apple ▪ Epiglottis – elastic cartilage that closes the tube off so food goes to the esophagus ▪ Vocal cords are inferior to epiglottis, larger folds produce a deeper voice 22.1 - Trachea ▪ Known as the windpipe, extends to the lungs, 16-20 pieces of C shaped hyaline cartilage connected by dense connective tissue 22.1 – Bronchial Tree ▪ Right and left primary bronchi branch at the carina ▪ Carina has special nerves to induce violent coughing if a foreign body is present ▪ Moves air in and out of lungs directly in addition to mucus membranes to trap debris and pathogens 22.1 – Respiratory Zone ▪ Structures are directly involved in the gas exchange ▪ Begins at the respiratory bronchiole ▪ Alveoli – where the gas exchange happens, they are clustered into alveolar sacs, cells are highly permeable to gases, have alveolar macrophages for protection ▪ Respiratory membrane – epithelium and endothelium combine to form a very thin membrane letting gases cross by simple diffusion 22.2 – The Lungs ▪ Contain conducting and respiratory zones ▪ Performs oxygen and carbon dioxide exchange ▪ Surface is about 70 square meters, highly permeable to gases ▪ The apex is superior and the base is near the diaphragm ▪ Left has 2 lobes and right has 3 lobes 22.2 ▪ Blood comes from pulmonary trunk ▪ Pulmonary capillaries lack smooth muscle ▪ Parasympathetic system causes bronchoconstriction ▪ Sympathetic system causes bronchodilation ▪ Each lung is enclosed in a cavity surrounded by pleura, visceral (inner) and parietal (outer). The space between layers is the pleural cavity ▪ Parietal pleura connects to thoracic wall, mediastinum, and the diaphragm 22.3 – The Process of Breathing ▪ Pulmonary ventilation – the act of breathing, moving air in and out of the lungs is based on the relationship of pressure ▪ Boyle’s law – the pressure of gas is inversely proportional to its volume ▪ Atmospheric pressure – amount of force exerted by the air, often in mm Hg ▪ Intra-alveolar pressure – pressure of air in alveoli, always equalizes with atmospheric pressure ▪ Intrapleural pressure – air pressure in the pleural cavity, always lower than intra-alveolar pressure