NURS 8022 Advanced Pathophysiology Exam 3 & Study Guide

Respiratory Structures of pulmonary system − NOT ON STUDY GUIDE • Lobes (3 on right, 2 on left) - segments − lobules • Blood vessels serve the pulmonary system • Chest wall/thoracic cage • Diaphragm: involved in ventilation − dome shaped muscle that separates the thoracic and abdominal cavities • Mediastinum: space between lungs containing heart, great vessels, and esophagus • Conducting airways o Upper airways: warms and humifies air  Nasopharynx and oropharynx o Larynx: connects upper and lower airways o Lower airways  Trachea, bronchi, terminal bronchioles • Carina: ridge where the trachea divides into the right and left bronchi • Hila: where the right and left bronchi enter the lungs, along with blood and lymph vessels • Goblet cells: produce mucus • Cilia: hair-like structures − work with goblet cells to propel foreign material up and enable it to be coughed up • Pleura: serous membrane − adheres firmly to the lungs and folds over itself o Visceral: covering the lungs; Parietal: lining the thoracic cavity o Pleural space: fluid lubricates the pleural surfaces allowing them to slide over each other  Pressure in pleural space: negative (-4 to −10); keeps lungs from collapsing  Inspiration − chest cage pulled outward on lungs creates greater negative pressure Understand basic structure and function of alveoli • Gas exchange airways: acinus - “berry” o Respiratory bronchioles o Alveolar ducts o Alveoli  Primary gas exchange units  Oxygen enters the blood and carbon dioxide is removed  Epithelial cells • Type 1 alveolar cells: provide alveolar structure • Type 2 alveolar cells: surfactant production − prevents lung collapse  Contain alveolar macrophages: ingest foreign material and remove it through lymphatic system Surfactant − its function and where it comes from • Detergent like substance secreted by type 2 alveolar epithelial cells in lungs • Keeps alveoli open and free of fluid and pathogens (collectins) • Decrease surface tension by blocking H20 and H+ binding in alveolar space − prevents collapse − allow airflow in more easily Understand the mechanics of the pulmonary circulation and how it relates to systemic circulation • Pulmonary circulation functions: o Facilitate gas exchange o Deliver nutrients to lung tissue o Acts as a blood reservoir for the left ventricle o Serves as a filtering system that removes clots, air, and other debris from the circulation o Pulmonary system pressure is 18 mmHg compared to systemic circulation of 90 mmHg o Gas exchange airways are served by the pulmonary circulation  Low pressure system, high flow − Supplies venous blood from all parts of the body to the alveolar capillaries where O2 is added and CO is removed; contains 100% of CO o Bronchi and other lung structures are served by systemic circulation − bronchial circulation  High pressure system, low flow − supplies blood to trachea, bronchial tree, bronchioles, and out coats (adventia) of pulmonary arteries and veins; contains 1-3% of CO • Pulmonary circulation o Begins at the pulmonary artery, which receives venous blood from the right side of the heart. The pulmonary artery divides into the left and right branches and forms the capillaries that surround the alveoli. After blood is oxygenated via gas exchange, blood returns to the left side of the heart through the pulmonary veins. • Pulmonary artery and accompanying smaller arteries and arterioles have large diameter; systemic vessels are small o Gives the pulmonary artery tree large compliance - accommodate stroke volume and pressure from RV • Pulmonary capillaries surround the acinus • Alveolocapillary membrane o Formed by shared alveolar and capillary walls o Contains the pulmonary capillaries o Where gas exchange occurs