L25- Respiratory System Anatomy of Lower Respiratory Tract PDF

L25- RESPIRATORY SYSTEM Anatomy of Lower Respiratory Tract Dr.Pugazhandhi Bakthavatchalam Assistant Professor of Anatomy and Physiology, AUACAS, American University of Antigua LEARNING OUTCOMES List and describe the bones forming the thoracic cage Describe the boundar...

L25- RESPIRATORY SYSTEM Anatomy of Lower Respiratory Tract Dr.Pugazhandhi Bakthavatchalam Assistant Professor of Anatomy and Physiology, AUACAS, American University of Antigua LEARNING OUTCOMES List and describe the bones forming the thoracic cage Describe the boundaries of the apertures of thoracic cage and list the structures traversing through these Describe the anatomy of the diaphragm Discuss the clinical significance of sternum Thoracic viscera: pulmonary cavities and mediastinum, anatomy of the pleura and pleural cavity and Lungs  BONES FORMING THE THORACIC CAGE  THORAX: Region of the body between the neck and abdomen Flattened in front and behind, but rounded on the sides The bony framework of the walls is called the thoracic cage, which is formed of: Vertebral column posteriorly Ribs & intercostal spaces on the sides Sternum and costal cartilages anteriorly  Forms protective cage around heart, lungs, and other organs http://www.kidport.com/reflib/science/human body/skeletalsystem/images/RibCageSideView. 8-Oct-24 jpg  THE BONY THORAX  Sternum Manubrium, Body, Xiphoid Process  Ribs 7 True Ribs 5 False Ribs  Vertebrae Thoracic https://www.netterimages.com/images/vpv/0 00/000/009/9892-0550x0475.jpg 8-Oct-24 4  THE STERNUM  Composed of fused sternebrae  Manubrium Jugular (sternal) notch Articulation with rib #1 & 2 Clavicular Articular facets Sternal Angle – 2nd rib  Body Articulates w/ribs 2-7 Xiphisternal joint  Xiphoid process Cartilage-calcifies through time Partial attachment of many http://image.slidesharecdn.com/thorax-and- lungs-learning-and-understanding- muscles objectives1724/95/thorax-4- 638.jpg?cb=1422637801 8-Oct-24 5  THE RIBS  Usually, 12 pairs 7 True ribs-direct attachment to sternum 5 False ribs-indirect or no attachment to sternum Floating ribs-make up 2 of 5 False ribs, no ventral attachment  Typical Ribs Ribs: 3-9 http://www.pleasanton.k12.ca.us/fhsweb/cuoz  Atypical Ribs zo/Handouts/06skeletal/Images/11%20thoraci Ribs: 1,2, 10, 11, 12 c%20cage.jpg 8-Oct-24 6  RIB ANATOMY Typical Ribs Head Neck Tubercle Angle Shaft Subcostal Groove 8-Oct-24 7  RIB ANATOMY  Atypical Ribs (1st, 2nd,10th -12th) 1 rib -short, flat (S-I), wide, Supports Subclavian vessels 2nd rib is long and flat 10th -12th ribs articulate with only with vertebra 11th , 12th don’t articulate with transverse processes posteriorly and NETTER ATLAS OF ANATOMY sternum anteriorly 8-Oct-24 8  THORACIC VERTEBRAE (12)  Identified by the presence of: Transverse Costal Facets Costal facets on vertebral body Spinous Processes long, point inferiorly Superior Articular Facets face Dorsally/Posteriorly Inferior Articular Facets face Ventrally/Anteriorly Vertebral Foramen is Circular Body is Heart-shaped 8-Oct-24 9  THORACIC VERTEBRAE  CLASSIFICATION OF THORACIC VERTEBRA: Typical- 2nd to 8th Atypical- 1st and 9th-12th  A vertebra of any regions presents the following general features:  A body in front, a vertebral arch behind and a vertebral canal between them  The vertebral arch consists of: a pair of pedicles, a pair of lamina and supports 7 process - a pair of transverse process, pairs of superior and inferior articular process and unpaired spinous process 8-Oct-24 10 BOUNDARIES OF THE APERTURES OF THORACIC CAGE  Thoraci cage: osseo(bony)cartilaginous  Is elastic  Function – Respiration BOUNDARIES Anteriorly – Sternum. Posteriorly – T1-T12, Intervertebral Discs. Laterally – 12 Ribs, Costal Cartilages. SHAPE- Truncated cone  Has inlet and outlet 8-Oct-24 11 INLET OF THORAX (SUPERIOR APERTURE)  Narrow.  Kidney shaped.  BOUNDARIES: Anteriorly – manubrium sterni. Posteriorly –T1 body. Laterally – 1st rib + cartilage.  STRUCTURES PASSING:  VISCERA 1. Trachea 2. Oesophagus 3. Lung apices 4. Remnants of thymus. 8-Oct-24 12 INLET OF THORAX (SUPERIOR APERTURE)  LARGE VESSELS 1. Brachiocephalic Artery 2. Left common carotid Artery 3. Left subclavian Artery 4. Right and Left Brachiocephalic veins  MUSCLES- Sternohyoid,Sternothyroid,Longus colli.  NERVES 1. Right and left Phrenic N 2. Right and Left Vagus N 3. Right and Left Sympathetic Trunks 4. Right and Left 1st Thoracic N. 8-Oct-24 13 THORACIC OUTLET (INFERIOR APERTURE)  Diaphragm is present  BOUNDRIES Anteriorly – infrasternal angle Posteriorly –T12 body Laterally – costal margin (7th to 12th ribs) 8-Oct-24 14 DIAPHRAGM http://antranik.org/wp- content/uploads/2011/10/diaphragm- superior-view.jpg   It is dome shaped musculo- aponeurotic partition, between thorax & abdomen  Convex superior surface faces thorax  Depressed in the middle, summits are known as CUPOLAE  Right cupolae is higher,due to the presence of liver  Peripheral part is muscular (striated)  Central part is tendinous– occupied by central tendon. http://www.crossfitsouthbay.com/muscle- spotlight-diaphragm/ 8-Oct-24 16   Origin of the diaphragm: A sternal part arising from the posterior surface of the xiphoid process A costal part arising from the deep surfaces of the lower six ribs and their costal cartilages & forms the right & left domes A vertebral/lumbar part arising from upper three lumbar vertebrae; forms the right & left crura & the arcuate ligaments (medial & lateral) 8-Oct-24 17   Insertion: The diaphragm is inserted into a central tendon. Some of the muscle fibers of the right crus pass up to the left and surround the esophageal orifice in a slinglike loop. These fibers appear to act as a sphincter and possibly assist in the prevention of regurgitation of the stomach contents into the thoracic part of the SNELLS REGIONAL ANATOMY esophagus. 8-Oct-24 18  OPENINGS IN THE DIAPHRAGM  The diaphragm has Major & Minor openings: Major openings are three : 1. The vena caval opening: - lies at the level of the T 8 vertebra in the central tendon. - Inferior vena cava & branches of the right phrenic nerve. 2. The esophageal opening: - lies at the level of the T 10 vertebra - Esophagus, the right and left vagus nerves, the esophageal branches of the left gastric vessels, & the lymph vessels 3. The aortic opening: - lies anterior to the body of the T 12 vertebra between the crura - Aorta, thoracic duct, & azygos vein  Minor openings: space of LARREY :- sternal origin &7th costal cartilage. - Transmits superior epigastric vessels, few lympahatics of liver, - When the opening is enlarged “foramen of Morgagni” B.D.CHAURASIA-TEXTBOOK OF ANATOMY  Minor openings: Greater & lesser splanchnic nerves-right crus & left crus Left phrenic nerve – piercing left cupola Sympathetic trunk, least splanchnic nerve -medial arcuate ligament. Musculophrenic vessels B.D.CHAURASIA-TEXTBOOK OF ANATOMY Subcostal vessels,nerve NERVE SUPPLY.  Motor supply; phrenic nerve.  Sensory supply; Central part; phrenic nerve. Peripheral part; lower 6 or 7 intercostal nerves.  Sympathetic, coeliac plexus. BLOOD SUPPLY Musculo-phrenic,pericardio-phrenic arteries - branches of internal thoracic artery. Lower 5 or 6 posterior intercostal arteries. Superior phrenic artery. Branch of descending thoracic aorta. Inferior phrenic artery. Veins corresepond with the arteries, drain into the systemic veins.  CLINICAL SIGNIFICANCE OF STERNUM  Sternum is the preferred site for bone marrow aspiration because it is subcutaneous and readily accessible  FUNNEL CHEST (PECTUS EXCAVATUM): An abnormality in the shape of the chest wall Is also known as sunken chest or funnel chest Ribs and sternum grow inward and form a dent in the chest. It can be mild or severe and when it's severe, there can be problems with the heart and lungs. 8-Oct-24 24  CLINICAL SIGNIFICANCE OF STERNUM  PIGEON CHEST (PECTUS CARINATUM): An abnormality in the shape of the chest wall Is a congenital deformation of the anterior chest wall. The condition presents with an outward protrusion of the sternum or rib cage. When the sternal manubrium is prominent, the deformity is often called “pigeon breast,” May also be caused by rickets due to deposition of unmineralized osteoid. 8-Oct-24 25  RELATION OF LOWER RIBS TO THE LIVER AND SPLEEN 8-Oct-24 26 THE LUNGS 27  Pair of essential organs of respiration lying in the thoracic cavity on either side of mediastinum 28 LUNGS APEX BASE COSTAL SURFACE MEDIAL SURFACE 29  APEX Above the border of the first rib Close to the blood vessels and nerves in the root of the neck 30 BASE Related to the thoracic surface of the diaphragm 31 COSTAL SURFACE Convex Costal cartilage, ribs and intercostal muscles 32 MEDIAL SURFACE Concave Has a hilum at the level of 5th,6th and 7th thoracic vertebrae Root of the lung enter and leave at the hilum 33 NOTE : Structures entering and leaving the lung form the lung root - primary bronchus - pulmonary artery - two pulmonary veins - bronchial arteries and veins - lymphatic - nerves 34 Mediastinum is the area between the lungs - heart - great vessels - trachea - right and left bronchi - esophagus -lymph nodes - lymph vessels and nerves 35 RIGHT LUNG LEFT LUNG - 3 LOBES - 2 LOBES 36 PLEURA AND PLEURAL CAVITY 37 PLEURAL MEMBRANES PARIETAL PLEURA VISCERAL PLEURA PLEURAL CAVITY (SEROUS FLUID) 38 The two layers are continuous with each other at the hilum 39 HILUM: A depression or slit- like opening 40 41  a. Right costal Margin b. 6 to 10 ribs of rt. Side The level of the lower border The level of the lower border of the left lung may be of the right lung may be indicated by drawing a indicated by drawing a shallow curved line Joining shallow curved line Joining the sternal end of the 7th rib the sternal end of the 6th rib in the midclavicular line, 8th in the midclavicular line, 8th rib in the mid axillary line and rib in the mid axillary line and 11th rib adjascent to the 10th rib adjascent to the vertebral column. vertebral column. a. Left Costal margin b. 7th & 8th left costal cartilage Xiphoid process The inferior margin of the parietal pleura takes an oblique path laterally from the level of rib 8 in the midclavicular line to rib 10 in the midaxillary line and the T12 vertebra at the vertebral column. Parietal Pleura  The two layers can be pulled apart but with slight level of difficulty because of the surface tension between them 44 INTERIOR OF THE LUNG Bronchi Smaller air passages Alveoli Connective tissue Blood vessels Lymph vessels and nerves All the above are embedded in ELASTIC connective tissue 45 PULMONARY BLOOD SUPPLY 46 BRONCHI AND BRONCHIOLES Trachea divides at the level of the 5th thoracic vertebrae 47  RIGHT BRONCHUS Wider, shorter and more vertical than left bronchus More likely to be obstructed by inhaled body 48  After entering the lung it divides into 3 lobar bronchi 49  LEFT BRONCHUS Longer, narrower and oblique After entering the lung it divides into two branches 50 STRUCTURE The conducting passages are thick walled 51  Towards the end the cartilage becomes irregular in shape At the level of bronchiole cartilage is absent 52 In place of cartilage smooth muscle in the wall of the bronchioles increases They become responsive to ANS stimulation and irritation 53 EPITHELIAL CHANGE Ciliated columnar Non ciliated cuboidal Squamous epithelium 54 BLOOD SUPPLY Right and left bronchial arteries VENOUS DRAINAGE Right side – azygos vein Left side -- superior intercostal vein 55 NERVE SUPPLY Vagus nerve – bronchoconstriction Sympathetic - bronchodilatoin 56 RESPIRATORY BRONCHIOLES AND ALVEOLI Each lung is further divided by fine sheets of connective tissue into LOBULES 57 58 As airway divides and becomes smaller and smaller the wall becomes thinner and thinner with gradual decrease in the smooth muscle and connective tissue 59  Alveolar ducts and alveoli have a single layer of squamous epithelium These distal passages are supported by elastic fibers 60 Supported by ELASTIC FIBERS 61 Surrounded by dense network of capillaries 62 Respiratory membrane 63  Between squamous cells are septal cells (type II pnuemocytes) Produce SURFACTANT It reduces the surface tension Production begins in the 24th to 35th week of fetal life 64 NERVE SUPPLY Parasympathetic – vagus - bronchoconstriction Sympathetic - bronchodilation 65 FUNCTION Defense against microbes defense relies on protective cells present within the lung tissue - plasma cells - macrophages - lymphocytes These act in the distal air passages 66  REFERENCES Drake R.L., Gray’s Anatomy for Students, 2nd Edition, 2009, Churchill Livingstone Moore, Clinically Oriented Anatomy, 6th Edition, 2009, Lippincott Williams & Wilkins Standring, Gray’s Anatomy: The Anatomical Basis of Clinical Practice, 40thEdition, 2008 Johannes W Rohen, Color Atlas of Anatomy: A photographic study of the human body, 7th Edition, 8-Oct-24 Lippincott Williams & Wilkins 67