RESPIRATORY SYSTEM ANATOMY AND PHYSIOLOGY

PYRAMID POINTS Functions of each part of the respiratory system Alterations that occur in the various parts of the respiratory system The effect on the respiratory system when a disorder occurs The function of the alveoli and the respiratory process The effect of treatments and procedures on the respiratory process

RESPIRATORY SYSTEM PRIMARY FUNCTIONS Provides oxygen for metabolism in the tissues Removes carbon dioxide, the waste product of metabolism SECONDARY FUNCTIONS Facilitates sense of smell Produces speech Maintains acid-base balance Maintains body water levels Maintains heat balance

UPPER RESPIRATORY TRACT Nose Sinuses Pharynx Larynx Epiglottis

UPPER RESPIRATORY TRACT From Monahan, F. & Neighbors, M. (1998). Medical-surgical nursing: Foundations for clinical practice, ed 2, Philadelphia: W.B. Saunders.

UPPER RESPIRATORY TRACT NOSE Humidifies, warms, and filters inspired air SINUSES Air-filled cavities within the hollow bones that surround the nasal passages Provide resonance during speech

UPPER RESPIRATORY TRACT PHARYNX Located behind the oral and nasal cavities Divided into the nasopharynx, oropharynx, and laryngopharynx Passageway for both the respiratory and digestive tracts

UPPER RESPIRATORY TRACT LARYNX Located above the trachea and just below the pharynx at the root of the tongue Commonly called the voice box Contains two pairs of vocal cords, the false and true cords The opening between the true vocal cords is the glottis The glottis plays an important role in coughing, which is the most fundamental defense mechanism of the lungs

UPPER RESPIRATORY TRACT EPIGLOTTIS Leaf-shape elastic structure that is attached along one end to the top of the larynx It prevents food from entering the tracheobronchial tree by closing over the glottis during swallowing

LOWER RESPIRATORY TRACT Trachea Mainstem bronchi Bronchioles Alveolar ducts and alveoli Lungs

LOWER RESPIRATORY TRACT From Monahan, F. & Neighbors, M. (1998). Medical-surgical nursing: Foundations for clinical practice, ed 2, Philadelphia: W.B. Saunders.

LOWER RESPIRATORY TRACT TRACHEA Located in front of the esophagus Branches into the right and left mainstem bronchi at the carina

TRACHEA From Wilson SF, Giddens JF: Health Assessment for Nursing Practice, ed. 2, St. Louis, 2001, Mosby.

LOWER RESPIRATORY TRACT MAIN STEM BRONCHI Begins at the carina The right bronchus is slightly wider, shorter, and more vertical than the left bronchus The mainstem bronchi divide into five secondary or lobar bronchi that enter each of the five lobes of the lung The bronchi are lined with cilia, which propel mucus up and away from the lower airway to the trachea where it can be expectorated or swallowed

LOWER RESPIRATORY TRACT BRONCHIOLES Branch from the secondary bronchi and subdivide into the small terminal and respiratory bronchioles They contain no cartilage and depend on the elastic recoil of the lung for patency The terminal bronchioles contain no cilia and do not participate in gas exchange

BRONCHIOLE From Monahan, F. & Neighbors, M. (1998). Medical-surgical nursing: Foundations for clinical practice, ed 2, Philadelphia: W.B. Saunders.

LOWER RESPIRATORY TRACT ALVEOLAR DUCTS AND ALVEOLI Alveolar ducts branch from the respiratory bronchioles Alveolar sacs, which arise from the ducts, contain clusters of alveoli, which are the basic units of gas exchange Cells in the walls of the alveoli secrete surfactant, a phospholipid protein that reduces the surface tension in the alveoli; without surfactant, the alveoli would collapse

ALVEOLI From Thibodeau GA, Patton KT: Anatomy and Physiology, ed. 4, St. Louis, 1999, Mosby. Courtesy of Network Graphics.

LOWER RESPIRATORY TRACT LUNGS Located in the pleural cavity in the thorax Extend from just above the clavicles to the diaphragm, the major muscle of inspiration The right lung, which is larger than the left, is divided into three lobes: the upper, middle, and lower lobe The left lung, which is somewhat narrower than the right lung to accommodate the heart, is divided into two lobes

LOWER RESPIRATORY TRACT LUNGS Innervation of the respiratory structures is accomplished by the phrenic nerve, vagus nerve, and thoracic nerves The parietal pleura lines the inside of the thoracic cavity, including the upper surface of the diaphragm The visceral pleura covers the pulmonary surfaces

LOWER RESPIRATORY TRACT LUNGS A thin fluid layer which is produced by the cells lining the pleura, lubricates the visceral and parietal pleura, allowing them to glide smoothly and painlessly during respiration Blood flow through the lungs occurs via the pulmonary system and the bronchial system

ACCESSORY MUSCLES OF RESPIRATION SCALENE MUSCLES Elevate the first two ribs STERNOCLEIDOMASTOID MUSCLES Raise the sternum TRAPEZIUS AND PECTORALIS MUSCLES Fix the shoulders

THE RESPIRATORY PROCESS The diaphragm descends into the abdominal cavity during inspiration, causing negative pressure in the lungs The negative pressure draws air from the area of greater pressure, the atmosphere, into the area of lesser pressure, the lungs In the lungs, air passes through the terminal bronchioles into the alveoli to oxygenate the body tissues

THE RESPIRATORY PROCESS At the end of inspiration, the diaphragm and intercostal muscles relax and the lungs recoil As the lungs recoil, pressure within the lungs becomes greater than atmospheric pressure, causing the air, which now contains the cellular waste products of carbon dioxide and water, to move from the alveoli in the lungs to the atmosphere Expiration is a passive process

DIAPHRAGM From Herlihy B, Maebius NK: The human body in health and illness, Philadelphia, 2000, W.B. Saunders.

INSPIRATION AND EXPIRATION From Monahan, F. & Neighbors, M. (1998). Medical-surgical nursing: Foundations for clinical practice, ed 2, Philadelphia: W.B. Saunders.