Trachea, Bronchi and Lungs Benish Islam Coordinator Lecturer Surgical (IPMs) kmu

Trachea Mobile cartilaginous, membranous tube. Begins at neck, lower border of cricoid cartilage. (at level of 6th cervical vertebra) In thorax trachea ends at Carina by dividing into principle (main) bronchi. (Level of sternal angle, 4th 5th thoracic vertebra)

Cont. Right: azygous vein,rt. Vagus nerve, pleura In adults:4 ½ inch long 1 inch diameter. U shped bars (rings) of hyaline crtilage embedded in wall. Anterior: sternum,thymus,lt. bracheocephalic vein,lt. bcommon caroti arteries,arch of aorta Posterior: esophagus, lt recurrent laryngeal nerve Right: azygous vein,rt. Vagus nerve, pleura Left: arch of aorta, lt subclavian, lt common carotid,phrenic nerves, pleura. Arterial supply:upper 2/3 inf. Thyroid arteries Lower 1/3 bronchial arteries Lymph nodes:pre tracheal,para tracheal,deep cervical nodes. Nerve Supply: sessory supply from vagi and recurrent laryngeal nerves.

Bronchi Trachea bifurcates into rt. and lt. principal (primary) bronchi. Rt. Principal bronchi is wider shorter, vertical 1inch. Before entering hilum gives superior lobar bronchus. On entering hilum it divides into: Middle, inferior lobar bronchus Left principal bronchi: narrow, longer, more horizontal, 2 inch On entering hilum divides into: Superior, inferior lobar bronchus

Lungs

Lungs Apex: projects upward into neck 1 inch above clavicle. Costal surface: convex Mediastinal surface: concave,molds to pericardium Hilum: bronchi vessels and nerves form root,enter and leave lung. Anterior border is thin,overlaps heart Cardiac notch on lt. lung.

Lobes and fissures of lungs

Bronchopulmonary segment

Bronchopulmonary segment Lobar secondary bronchus Segmental (tertiary) bronchi (for each bronco pulmonary segment) Bronchioles(1 mm diameter) Terminal bronchioles-(Respiratory bronchioles 0.5mm) Alveolar ducts Alveolar sacs (gaseous exchange)

Blood Supply Arterial supply: bronchial artery Bronchi, lung, pleura Alveoli Arterial supply: bronchial artery (Branches of descending aorta) Bronchial veins-communicates with pulmonary veins (drains into hemizygos Azygos veins) Alveoli receives deoxygenated blood from branches of pulmonary arteries. Oxygenated blood drains into tributaries of pulmonary veins.

Lymphatic supply Superficial plexus drains to broncho pulmonary nodes at hilum. Deep plexus travels along bronchi, pass through pulmonary nodes. All lymph from lungs drains to tracheobronchial nodes and then to bronchomediastinal lymph trunk.

Nerve supply Pulmonary plexus Sympathetic trunk + Para sympathetic fibers from vagus nerve Sympathetic efferent fibers cause bronchodilation and vasoconstriction Parasympathetic efferent fibers: bronchoconstrition,vasodilation, inc.glandular secretion, Afferent impulse from both sympathtic and parasym. Derives from stretch receptors in alveoli walls to central nervous system.

Summary