The Lungs
Definition
Organ of respiration
2 lungs - Right & Left
Right lung - 3 lobes : Upper, middle and lower lobes : 10 segments - 3 in the upper lobe, 2 in the middle lobe and 5 in the lower lobe
Left lung - 2 lobes : Upper and lower lobes : 8 segments - 4 in the upper lobe and4 in the lower lobe
The Pleura
A membrane covering the lung closely - Visceral pleura - forms invaginations called fissures - 2 fissures in the right lung and one in the left lung
Pulmonary ligament - a double layer of pleura along the mediastinum
Blood Supply
Pulmonary artery and pulmonary vein
Pulmonary artery from the right ventricle; the pulmonary vein from the alveoli
Pulmonary artery ends in the lung parenchyma; pulmonary vein empties into the left atrium
They enter and exit the lung through the hilum of the lung
The pulmonary artery divides into truncal, lobar, segmental and subsegmental arteries and follow the branches of the bronchial tree.
The veins from the alveoli receive blood from the bronchial and pleural branches. form 2 pulmonary veins, superior and inferior on each side; these 4 join at or near their junction with the left atrium and usually this common area is intrapericardial.
Pulmonary lymphatic system
Lymphatic vessels drain into intraparenchymal lymphatics and lymph nodes reach Hilar lymph nodes and then subcarinal, tracheobronchial and paratracheal lymph nodes and then ultimately reach the thoracic duct
Nerve Supply
Vagus nerves -Parasympathetic nerves
Sympatheric nerves from sympathetic trunks of the vagus nerves
Lymphatic Drainage
Drain to the pulmonary nodes → bronchopulmonary nodes → inferior (carinal) and superior tracheobronchial nodes → the tracheal (paratracheal) nodes → bronchomediastinal nodes and trunks, →thoracic duct on the left and right lymphatic duct on the right.
