Lungs Dr. Sama ul Haque

Objectives Define mediastinum. Discuss the anatomical structure of lungs. Enlist the relations of right and left lungs. Give the blood and nerve supply of the lungs.

Mediastinum Definition: A median septum or median partition between the two pleural cavities.

Boundaries of the Mediastinum Superior boundary: Superior thoracic aperture Inferior boundary: Diaphragm Anterior boundary: Sternum Posterior boundary: Bodies of vertebrae T1 to T12 Lateral boundaries: Mediastinal parietal pleura (left and right).

Gross Anatomy of the Lungs Each lung has a conical shape, concave base rests upon the muscular diaphragm. Its superior region is called Apex. Toward the midline, the lungs are separated from each other by the Mediastinum. The relatively broad, rounded surface in contact with the thoracic wall is called the Costal surface of the lung.

Lungs Left lung divided into 2 lobes by oblique fissure smaller than the right lung. cardiac notch accommodates the heart Right Lung divided into 3 lobes by oblique and horizontal fissure

Lungs and Pleura (Anterior view)

Lungs and Pleura (Posterior view)

Lungs An apex A base 3 borders: Anterior Posterior Inferior 2 surfaces: Medial and costal. Medial surface: Mediastinal & vertebral

Apex And Base of the lung It extends up 1 inch above and behind the medial third of the clavicle. Base: It is concave in shape . It is related to: 1- Diaphragmatic pleura. 2- Right copula of the diaphragm. 3- Liver (right lung) . Liver, stomach (fundus), and spleen (left lung).

Borders of the lung A. Anterior border It is a sharp border. The lower part of the anterior border of the left lung contains the cardiac notch (just below the cardiac notch there is a projection called the lingula). B. Posterior border It is a rounded border. C. Inferior border

Lobes &Fissures of the lungs Right lung Left lung Three lobes: Superior Middle Inferior Fissures: Oblique fissure Transverse fissure Two lobes Superior Inferior Fissure: Oblique fissure

Lobes and fissures of Lungs

Mediastinal Surface of the Right Lung Cardiac impression (Right atrium). Superior vena cava. Inferior vena cava. Right subclavian artery. Right brachiocephalic vein Azygos vein. Esophagus. Trachea. Thymus

Mediastinal Surface of the Left Lung Cardiac impression (Left ventricle). Arch of Aorta. Descending aorta. Left subclavian artery. Left brachiocephalic vein Thoracic duct. Esophagus. Trachea. Thymus

Hilum of the lungs It gives passage to the structures forming the Root of the lung. 1. Bronchus 2. Pulmonary artery 3. Pulmonary veins 4. Hilar lymph nodes. 5. Bronchial vessels. 6. Pulmonary plexuses 7. Pulmonary ligament Hilum of left lung Hilum of right lung

Difference between the right and left lungs Right Lung Left Lung Size and weight Larger and heavier Smaller and lighter Length and breadth Shorter and wider Longer and narrower Lobes Fissures Three Two Two lobes One fissure Anterior border No cardiac notch Cardiac notch and lingula.

Bronchial Tree

Bronchopulmonary Segments

Bronchopulmonary Segments

Respiratory Bronchioles, Alveolar Ducts, and Alveoli Lungs contain small sacs called alveoli. They have a thin wall specialized to promote diffusion of gases between the alveolus and the blood in the pulmonary capillaries.

Respiratory Bronchioles, Alveolar Ducts, and Alveoli Gas exchange can take place in the respiratory bronchioles and alveolar ducts as well as in the alveoli, each lung contains approximately 300 to 400 million alveoli. The spongy nature of the lung is due to the packing of millions of alveoli together.

Respiratory Bronchioles Alveolar Ducts And Alveoli

Blood supply of Lungs Pulmonary circulation: Bronchial circulation: Bronchial arteries supply oxygenated blood to lungs, bronchial veins carry away deoxygenated blood from lung tissue.

Pulmonary Circulation

Nerve supply Anterior and posterior pulmonary plexuses. a. Sympathetic component: (T2 to T5 sympathetic ganglia). b. Parasympathetic component (vagi)

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