2Objectives 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.
3Mediastinum Definition: A median septum or median partition between the two pleural cavities.
4Boundaries of the Mediastinum Superior boundary:Superior thoracic apertureInferior boundary:DiaphragmAnterior boundary:SternumPosterior boundary:Bodies of vertebrae T1 to T12Lateral boundaries:Mediastinal parietal pleura(left and right).
5Gross 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.
6Lungs Left lung divided into 2 lobes by oblique fissure smaller than the right lung.cardiac notch accommodates the heartRight Lungdivided into 3 lobes by oblique and horizontal fissure
9Lungs An apex A base 3 borders: Anterior Posterior Inferior 2 surfaces: Medial and costal.Medial surface: Mediastinal & vertebral
10Apex 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).
11Borders of the lungA. 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
12Lobes &Fissures of the lungs Right lungLeft lungThree lobes:SuperiorMiddleInferiorFissures:Oblique fissureTransverse fissureTwo lobesSuperiorInferiorFissure:Oblique fissure
18Hilum of the lungsIt 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 ligamentHilum of left lungHilum of right lung
19Difference between the right and left lungs Right LungLeft LungSize and weightLarger and heavierSmaller and lighterLength and breadthShorter and widerLonger and narrowerLobesFissuresThreeTwoTwo lobesOne fissureAnterior borderNo cardiac notchCardiac notch and lingula.
23Respiratory 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.
24Respiratory 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.