Lungs Anatomy PDF
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Summary
This document provides an overview of lung anatomy, including details on the structure and function of the lungs, the different components of the lungs and their roles in breathing, the pulmonary blood supply, and the bronchial tree. It covers various aspects ranging from the position of the lungs to the types of alveolar cells and blood supply to the respiratory membrane.
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Lungs Paired cone-shaped organs in thoracic cavity that separated by heart & other structures in mediastinum which divides thoracic cavity into 2 anatomically distinct chambers Pleural membrane Double layers of serous membrane that enclose lungs Parietal pleura li...
Lungs Paired cone-shaped organs in thoracic cavity that separated by heart & other structures in mediastinum which divides thoracic cavity into 2 anatomically distinct chambers Pleural membrane Double layers of serous membrane that enclose lungs Parietal pleura lines wall of thoracic cavity Visceral pleura lines lungs Pleural cavity space between parietal & visceral pleura that contains lubricating fluid secret by membranes Pleura fluid Reduce friction between membranes during breathing Adherence of membranes surface tension Lungs cont. Lungs cont. Position Concave base of lungs sits on convex area of diaphragm where it extends to just slightly superior to clavicles as apex Anterior, lateral & posterior surface of lungs lie against ribs, costal surface, matches rounded curvature of ribs Hilum At mediastinal surface where bronchi, pulmonary blood vessels, lymphatic vessels & nerves enter & exit Held by pleura & connective tissue root Cardiac notch Medial concavity at left lung due to heart Made left lung ~10% smaller than right lung Lungs cont. Fissures Divide lungs into lobes Oblique fissure Extends inferiorly & anteriorly Left lung separates superior lobe from inferior lobe Right lung superiorly, separates superior lobe from inferior lobe & inferiorly, separates inferior lobe from middle lobe Horizontal fissure Separates superior lobe from middle lobe Lobes Each receives 2º bronchus Lungs cont. Bronchopulmonary segment Each receives a 3º bronchus Contains many lobules Lobules Wrapped with connective tissue & contains a lymphatic vessel, an arteriole, a venule & a branch from terminal bronchiole In each lobule, terminal bronchiole subdivides into branches of respiratory bronchioles & further subdivides into alveolar ducts Lungs cont. Alveoli Cup-shaped outpouching lined by simple squamous epit. & supported by a thin elastic basement membrane (alveolar sac) Types of alveolar cells Type I alveolar cell Simple squamous epit. Alveolar Main site for of gas exchange ducts Type II alveolar cell (septal cells) Alveolar Fewer & found between type I sac Rounded or cuboidal epit. with microvilli Alveoli Secrete alveolar fluid to keeps surface between cells & air moist Secrete alveolar fluid that contains surfactant (complex mixture of phospholipid & lipoprotein). Surfactant lowers surface tension of alveolar fluid which reduces tendency of alveoli to collapse Lungs cont. Alveolar macrophages Remove fine dust particles & other debris from alveolar spaces Fibroblast Produce reticular & elastic fibers Respiratory membrane Exchange of O2 & CO2 between alveolar air space & blood by diffusion Consists of Alveolar wall (type I, II & macrophages) Basement membrane of alveolar wall Capillary endothelium Basement membrane of capillary endothelium Lungs cont. Blood supply Pulmonary arteries Right ventricle pulmonary trunk right & left pulmonary artery lungs pulmonary veins (2 left & 2 right) left atrium Unique feature Constriction in response to localized hypoxia Diverts pulmonary blood from poorly ventilated area of lungs to well- ventilated area ventilation-perfusion coupling perfusion (blood flow) to each area of lungs matches the extent of ventilation (airflow) to alveoli in that area Bronchial arteries Branch from aorta Perfuses muscular walls of bronchi & bronchioles deliver oxygenated blood to the lungs Bronchial tree Trachea 1˚ bronchi (right & left) 2˚ bronchi (3 right & 2 left) 3˚ bronchi bronchioles terminal bronchioles respiratory bronchioles alveolar ducts Epithelial changes Pseudostratified ciliated columnar (trachea,1˚, 2˚, 3˚) ciliated simple columnar with goblet cells (larger bronchioles) ciliated simple cuboidal with no goblet cells (smaller bronchioles) nonciliated simple cuboidal (terminal bronchiole) simple cuboidal (respiratory bronchiole) simple squamous (alveoli) Lung segmentation Lobes bronchopulmonary segment lobule
