Respiratory Tract 2 - Lower Respiratory Tract PDF

Anatomy of the Respiratory Tract 2 Lower respiratory tract: Bronchial Tree Niggy Gouldsborough Lower Respiratory Tract Trachea Primary bronchi Secondary bronchi Tertiary bronchi Bronchioles Terminal bronchioles Respirat...

Anatomy of the Respiratory Tract 2 Lower respiratory tract: Bronchial Tree Niggy Gouldsborough Lower Respiratory Tract Trachea Primary bronchi Secondary bronchi Tertiary bronchi Bronchioles Terminal bronchioles Respiratory bronchioles Alveolar ducts Alveolar sacs Alveoli  Trachea Tough, flexible tube, 4.5cm long, 2.5cm in diameter Extends from larynx to the carina trachea Lies anterior to the oesophagus carina  Trachea Contains 15-20 Trachealis muscle Oesophagus horseshoe shaped cartilages which keep airway open Trachea Posterior ends of cartilage are joined by trachealis muscle which constricts during Cartilage coughing Pseudostratified Trachea lined by ciliated columnar epithelium with goblet pseudostratified ciliated (Ashton, 2015) cells columnar epithelium Pseudostratified Ciliated Columnar Epithelium with Goblet Cells Acts as a mucociliary dust particle escalator mucus layer cilia goblet cell  Bronchial Tree Branching network of air tubes Bronchi – Primary – Secondary – Tertiary Bronchioles – Bronchioles – Terminal bronchioles – Respiratory bronchioles (Ashton, 2015)  Bronchial Tree Series of tubes that get smaller in diameter and display other histological changes – amount of cartilage decreases – amount of smooth muscle increases – height of epithelial cells decrease  Bronchi C shaped cartilage Primary bronchi supply each lung 2-3cm long primary right is wider and more vertical bronchus than left secondary C-shaped cartilages cartilage plate bronchus Secondary bronchi (lobar) supply lobes of the lung (3 on right, 2 on tertiary bronchi left) plates of cartilage cartilage plate Tertiary bronchi (segmental) supply segments of the lung (10 on right, 8 on left) plates of cartilage (Ashton, 2015)  Bronchus Pseudostratified ciliated columnar epithelium with goblet cells Cartilage plates  Bronchiolar Bronchioles No cartilage Structure Simple columnar epithelium with cilia Few goblet cells Smooth muscle  can constrict and dilate Each gives rise to 50-80 terminal bronchioles Terminal bronchioles Simple columnar epithelium with cilia bronchiole No goblet cells or mucous glands Clara cells – produce surfactant terminal bronchiole Each gives rise to 2 or more respiratory bronchioles respiratory bronchiole Respiratory bronchioles Simple cuboidal epithelia (Ashton, 2015) No cilia Clara cells – produce surfactant Alveoli extend from the lumen  gas exchange occurs here  Bronchioles alveoli Simple columnar epithelium with some goblet cells Respiratory bronchiole Smooth muscle in walls