1. Gross Anatomy of Lungs 6. Histopathology of Alveoli2. Surfaces and Borders of Lungs 7. Surfactant3. Hilum and Root of Lungs 8. Blood supply of lungs4. Fissures and Lobes of 9. Lymphatics of Lungs Lungs 10. Nerve supply of Lungs5. Bronchopulmonary 11. Pleura segments 12. Mediastinum
GROSS ANATOMY OF LUNGSLungs are a pair of respiratory organs situated in a thoracic cavity.Right and left lung are separated by the mediastinum.Texture -- SpongyColor – Young – brown Adults -- mottled black due to deposition of carbon particlesWeight- Right lung - 600 gms Left lung - 550 gms
APEXBlunt Grooved by- bLies above the level of Subclavian arteryanterior end of 1st Rib. Subclavian veinReaches 1-2 cm abovemedial 1/3rd of clavicle.Coverings – cervical pleura. suprapleural membane
BASESemilunar and concave.Rests on dome of Diaphragm.Right sided dome is higher than left.
BORDERS ANTERIOR BORDER –1. Corresponds to the anterior (Costomediastinal) line of pleural reflection.2. It is deeply notched in the left lung posterior to 5th costal cartilage by the pericardium and extends vertically downwards to form Lingula. This is called cardiac notch(percussion in this area gives a dull note as compared to dull note obtained over lung).
INFERIOR BORDERThin and sharpIt seperates the base of lung from thecostal surface and extends intophrenicocostal sinus.
POSTERIOR BORDERThick and ill definedFits into deep paravertebral gutter.Extends from C7 to T10.
SURFACES OF THE LUNG1. Costal Surface - It is in contact with costal pleura and overlying thoracic wall.2. Medial Surface - Posterior / Vertebral Part - Anterior / Mediastinal Part
RELATIONS OF ANTERIOR PART RIGHT SIDE LEFT SIDE1. Right atrium 1. Left ventricle2. Small part of RV 2. Pulmonary trunk3. SVC 3. Arch of Aorta4. Right brachiocephalic 4. Descending thoracic vein(lower part) aorta5. Azygos vein 5. Left Subclavian Artery6. Esophagus 6. Thoracic duct7. IVC 7. Left Brachiocephalic8. Trachea Vein9. Right vagus nerve 8. Left vagus nerve10. Right phrenic nerve 9. Left phrenic nerve 10. Left recurrent laryngeal nerve
HILUMIt is a large depressed area that liesnear the centre of the medial surface.Various structures enter and leave thelung via its root.
ROOT OF THE LUNGThe root is enclosed ina short tubular sheet ofpleura that joins thepulmonary andmediastinal parts ofpleura . It extendsinferiorly as a narrowfold - The pulmonaryligament.It lies opposite of thebodies of 5th, 6th and7th thoracic vertebra
STRUCTURES OF THE ROOT Principal Bronchus on the left side. Eparterial and Hyparterial on the right side. One pulmonary artery . Two pulmonary veins - Superior Inferior Bronchial arteries One on right side Two on left side
Bronchial veinsAnterior andposterior pulmonaryplexus of nerves.LymphaticsBronchopulmonaryLymphnodesAreolar tissue.
ARRANGEMENT OF STRUCTURES IN THE ROOT BEFORE BACKWARDS 1. Superior pulmonary vein. 2. Pulmonary artery. 3. Bronchus.
ARRANGEMENT OF STRUCTURES IN THE ROOT ABOVE DOWNWARDS A. Right Side 1. Eparterial Bronchus. 2. Pulmonary Artery. 3. Hyparterial Bronchus. 4. Inferior Pulmonary Vein. .
ARRANGEMENT OF STRUCTURES IN THE ROOT ABOVE DOWNWARDS B. Left Side 1. Pulmonary artery. 2. Bronchus. 3. Inferior pulmonary vein
OBLIQUE FISSUREIt begins posteriorly at the level of 5ththoracic vertebra.Passes antero-inferiorly in a spiralcourse to meet the inferior margin closeto 6th costochondral junction.
HORIZONTAL FISSUREIt extends from anterior margin at the level of4th costal cartilage.Runs horizontally backwards to meet theoblique fissure in the mid-axillary line.Pulmonary pleura extends into the fissures ofthe lungs so that the lobes can move on eachother during respiration.
BRONCHOPULMONARY SEGMENTSThese are well defined areas of thelungs, each of which is aerated by asegmental / tertiary bronchus.
TracheaRight and Left Principal BronchusLobar Bronchi(Secondary)[2L,3R]Segmental Bronchi(Tertiary)[8L,10R]Terminal Bronchioles(25000 in no.)Respiratory BronchiolesAlveolar ducts ACINUSAlveolar sacsAlveoli
The ultimate pulmonary unit from respiratorybrochiole to alveoli is called Acinus.There are about 28 orders of division oftracheo-bronchial tree.Total no. of alveoli has been estimated to bebetween 200 - 600 million, with a total surfacearea of 40 - 80 meter square.
BRONCHOPULMONARY SEGMENTS Right main bronchus Left main bronchus1. Shorter 1. Longer2. Wider. 2. Narrower.3. More in line with 3. More oblique than trachea. the right.
BRONCHOPULMONARY SEGMENTS Right Main BronchusRight upper lobe Bronchus Right Middle lobe Bronchus Right Lower Lobe BronchusSegmental Bronchi Segmental Bronchi Segmental Bronchi Apical Apical Medial Anterior Anterior Lateral Posterior Posterior Medial and Lateral
BRONCHOPULMONARY SEGMENTS Left Main Bronchus Left upper lobe Bronchus Left lower lobe bronchusUpper Branch Lower Branch Segmental Bronchi Apical Anterior Superior Lingular AnteriorApico-posterior Inferior Lingular Posterior Lateral
These segments are pyramidal in shape withapex towards the root of lung.Each segment is an independent respiratory unit.Each segment has its own separateartery(branches of pulmonary artery).Pulmonary Veins run in inter-segmental planesbetween adjoining segments.Thus a bronchopulmonary segment is not abronchovascular segment as it does not haveits own vein.
CLINICAL SIGNIFICANCESegmental resection with minimaldestruction to the surrounding lungtissue.To visualize the interior of a bronchithrough a bronchoscope when diseasesprocess is limited in a segment.
HISTOPATHOLOGY OF ALVEOLIALVEOLAR WALL1. Alveolar epithelial cells- Type I pneumocytes Type II pneumocytes2. Basement Membrane3. Interstitial Space- Collagen Elastin Unmyelinated Nerves Macrophages4. Capillary Basement Membrane5. Capillary Endothelial Cells. .
Type I PneumocytePavement epithelialcells of alveoli .Less in no. thantype II.More surfacearea(flattened)Contain pinocyticvesicles.Specialized fordiffusion of gases.
Type II PneumocytesMore numerous thantype I.Cuboidal in shape.Rich inmitochondria, ERand vacuolescontainingosmiophillic lamellarbodies.Type I areprecursors of type II.
ENDOTHELIAL CELLSMost numerous .Presence ofpinocytic vacuolesthat meet theluminal surface toform caveolae.Walls of caveolaehas, ACE.Source of NO,natural pulmonaryvasodilator.
ALVEOLAR MACROPHAGES Primary defence mechanism. Takes part in inflammatory and immunological reactions. Activates lysosomes , proteases,complement , thromboplastin, cytokines - IF-α, TNF- α, IL-1, IL-8.
SURFACTANTLines the inner layer of alveolar epithelium.Synthesized by SER of type II pneumocytes.Function –1. To reduce the surface tension of alveoli mainly during expiration, thus reduces the work of lung inflation.2. Waterproofing.Surfactant synthesis starts after 26 weeks offetal life. Therefore premature infants,withinsufficient surfactant suffer from HMD.