KIN 3304 1nd Edition Lecture 25Outline of Last Lecture I. Gas Diffusion cont.II. Questions/Answers of Exam 3Outline of Current Lecture I. Two TractsII. FunctionsIII. Primary BronchiIV. BronchiolesV. Respiratory BronchiolesVI. Alveolar Ducts and AlveoliVII. Alveolus and Respiratory MembraneVIII. Gas ExchangeIX. Blood Supply to LungsCurrent Lecture*Know what a collapsed lung looks likeI. Two tractsa. Upper respiratory systemi. Nose, nasal cavity, paranasal sinuses, pharynxii. Filter, warm, humidify airThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.iii. Protect delicate LRSb. Lower Respiratory Systemi. Larynx, tracheal, bronchi, lungsii. Gas exchangeII. Functionsa. Many – but we will focus on twoi. Gas exchange1. We’ll focus on this the most in HHPii. Move air to/from lung surfaceIII. Primary Bronchia. Trachea branches, gives rise to right and left primary (main) bronchii. Outside lungs (extrapulmonary bronchi)b. Travels to a groove (hilum) along lungi. Provides cross for pulmonary vessels, nervesii. Anchored with dense CT (rest of lung)*soon as you go unconscious, breathing resets*left lung is where the cardiac notch is located*Hb will drop O2 to pick up carbon monoxideIV. Bronchiolesa. Tertiary bronchus branches many timesi. ~6,500 smaller terminal bronchioles (0.2-0.5mm)b. ANS regulates activity, controls diameterc. Epithelium causes bronchodilation; parasympathetic stimulation = bronchoconstrictionV. Respiratory Bronchiolesa. Each terminal bronchiole delivers air to a single pulmonary lobuleb. Within lobule, t.b. branches (respiratory bronchioles)i. These deliver air to lung (surface exchange)ii. No mucus cells/glands here: few ciliaVI. Alveolar Ducts and Alveolia. Respiratory bronchioles connected to independent and multi alveoli along alveolar ductsi. End at alveolar sacsii. Common chambers connected to several alveoliiii. Upwards of 150,000,000 alveoliiv. Why the lung is “spongy” in appearanceb. Huge capillary network association with each alveolusi. Surrounded by elastic fiber (expansion)*Incubator is similar in relation to the lower respiratory tract because a lot of stuff can grow thereVII. Alveolus and Respiratory Membranea. Alveolar epithelium consists primarily of simple epitheliumi. Squamous epithelium cells (pneumocyte type 1, or type 1 alveolar cells) are thin, delicateii. Type 2 Alveolar Cells scattered among squamous cells1. Secrete surfactant – coats inner surface, reduces tension 2. Keep alveoli from collapsing (important)3. Also have alveolar macrophages – phagocytosisVIII. Gas Exchange **TQa. Occurs where basal laminae of alveolar epithelium and capillaries have fusedb. Rapid diffusion due to:i. Size (as small as 0.1 micrometer)ii. Gases are lipid solubleIX. Blood Supply to Lungsa. Respiratory exchange surfaces receive blood from arteries of the pulmonary circuitb. Each lobule receives an artery and a venulei. Capillary network surrounds each alveolusii. Primary source of angiotensin-converting hormone (converts circulating angiotensin 1 to angiotensin
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