BENISH ISLAM COORDINATOR LECTURER SURGICAL

( IPMS) KMU

Trachea, Bronchi and Lungs

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.

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 arteriesLymph 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: convexMediastinal surface: concave,molds to pericardiumHilum: 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)

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.

Blood Supply

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 plexusSympathetic trunk

+Para sympathetic fibers

from vagus nerveSympathetic 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