Thoracic Cavity

Right and Left Pleural Cavities  Parietal Pleura  Visceral (Pulmonary) Pleura  Parietal –Costal –Mediastinal –Diaphragmatic –Cupola  Connecting Pleura

Pleural Cavities

Lungs  Light, soft, spongy  Conical in shape, apex, base, costal surface, medial surface, hilus. Note various impressions  Right lung –Three lobes; superior, middle and inferior –Oblique and horizontal fissure  Left Lung –Two lobes; superior and inferior also Lingula and Cardiac notch, oblique fissure

Right Lung

Left Lung

Surface Anatomy

Airways  Trachea, primary bronchi, secondary bronchi, tertiary bronchi out to 25 generations  All comprised of hyaline cartilage  Trachea –Begins where larynx ends (about C6) –10 cm long, half in neck, half in mediastinum –20 U-Shaped rings of hyaline cartilage – keeps lumen intact but not as brittle as bone –Lined with epithelium and cilia which work to keep foreign bodies/irritants away from lungs

Airways

Trachea

Airways

 Primary Brochi  One to each lung – continuation of trachea –Right bronchus is wider and shorter 2.5 cm as opposed to 5 cm and branches from the trachea at a greater angle  Secondary bronchi – one to each lobe, three in right, two in left  Tertiary – one to each bronchopulmonary segment – approximately 10 per lung  All of the above are hyaline cartilage with no ability to change diameter

Bronchoscope

Tumor

In and Out

Bronchopulmonary Segments

Bronchioles  First level of airway surrounded by smooth muscle; therefore can change diameter as in brocho-constriction and broncho-dilation  Terminal  Respiratory  3-8 orders  alveoli

Bronchioles

 Gas Exchange  Pulmonary arteries carry deoxygenated blood to aleoli  Gas exchange occurs via diffusion through the capillary beds  Returned to heart via pulmonary veins

Gas Exchange

Innervation  Pleura via intercostal (thoracic) nerves  Tracheobronchial tree  Parasympathetic via CN X efferent function = broncho-constriction via smooth mm., also to epithelial cells in trachea; afferent = responsible for cough reflex  Sympathetic from T1-T5 efferent = brocho- dilation

Intercostal to Pleura

Innervation

Blood Supply  Lungs do not receive any vascular supply from the pulmonary vessels (pulmonary aa. or veins)  Blood delivered to lung tissue via the bronchiole arteries  Vessels evolve from aortic arch  Travel along the bronchial tree

Blood Supply