Anatomy of structures associated with the lower respiratory tract of the north american opossum (Didelphis virginiana)

RESUMO

This study documents the macroscopic anatomy of the associated structures of the lower respiratory tract of the North American opossum (Didelphis virginiana). Cranial deep cervical, cranial mediastinal and tracheobronchial lymph nodes drain the lower respiratory tract. Vascularization of the lungs is via the bronchial artery a branch of the bronchoesophageal artery. The bronchial artery divides into right and left bronchial arteries which follow the branches of the bronchial tree. The pulmonary arteries divide into pulmonary lobar arteries which follow the bronchial division. Pulmonary lobar veins from each lobe of the right and left lungs join to form three pulmonary veins (right, left and middle). The three pulmonary veins join to form a commom pulmonary venous trunk that opens into the left atrium of the heart. Sympathetic innervation to the lungs comes from the ipsilateral sympathetic trunks through the mediastinal pleura and pulmonary ligaments as thoracic splanchnic nerves. Parasympathetic innervation to the lungs is via branches from the ipsilateral vagus nerves. The right and left phrenic nerves are formed by components of ventral branches of cervical nerves 2 - 6 which pass through the cervical (C2-C4) and brachial (C5-C6) plexuses.