Respiratory System Part-4 ANAT 211, 212 and 213 PDF

Respiratory System Part-4 Anatomy Course ANAT 211, 212 and 213 Term 2, 2023-24 Basic Sciences Department, COSHP, KSAU-HS, KSA 1 Respiratory System Part- 4 By the end of this session the students should be able to: Discuss anatomy of the pleura (visceral pleura, parietal pleura and pleural cavity). D...

Respiratory System Part-4 Anatomy Course ANAT 211, 212 and 213 Term 2, 2023-24 Basic Sciences Department, COSHP, KSAU-HS, KSA 1 Respiratory System Part- 4 By the end of this session the students should be able to: Discuss anatomy of the pleura (visceral pleura, parietal pleura and pleural cavity). Describe the anatomy of tracheobronchial tree (from trachea to alveolus). Describe the anatomy of lungs in terms of location, shape, lobes, fissures, hilum and root. Discuss the bronchial and pulmonary circulation. Discuss the thoracic wall (bones, openings and names of muscles) Describe the diaphragm in terms of attachments, parts, openings and nerve supply 2 The Pleura and Pleural Cavities The pleura is a serous membrane which folds back onto itself to form a two-layered membrane structure. The thin space is known as the pleural cavity and contains a small amount of pleural fluid. Each pleural cavity is formed by two layers of parietal and visceral pleura. The pleura lining the thoracic wall is the parietal pleura, whereas that covers the lungs is the visceral pleura. A potential space, the pleural cavity is present between the visceral pleura and the parietal pleura. It contains pleural fluid which acts as lubricant and helps to hold parietal and visceral pleural membranes together. Parietal pleura is highly sensitive to pain, while visceral pleura is insensitive to pain. 3 Parts of the Parietal Pleura Subdivision of parietal pleura: The parts of the parietal pleura correspond to the wall with which they are associated: 1. Costal pleura is the pleura related to the ribs and intercostal spaces 2. Diaphragmatic pleura is the pleura covering the diaphragm 3. Mediastinal pleura is the pleura covering the mediastinum 4. Cervical pleura is the cervical extension of the pleural cavity Note: Costo-diaphragmatic recess is a space within pleural cavity bounded by diaphragmatic and the costal pleura covering the diaphragm and the thoracic wall. It provides a space for lung expansion and accumulates fluid in pleural effusion that is drained through thoracentesis. 4 The Trachea It is 10 cm long fibrocartilaginous tube with trachealis muscle behind. Extends from the cricoid cartilage (C6 vertebra) to the level of sternal angle (intervertebral disc between T4 and T5 vertebrae) Made up of 16-20 incomplete cartilaginous rings which provide rigidity to the tracheal wall and ensure that the trachea always remains open At the level of the sternal angle, the trachea bifurcates into the right and left primary bronchi Carina: internal medial ridge in the lowermost tracheal cartilage. It is highly sensitive area and generates strong cough when a foreign body enters in trachea and touches it 5 The Bronchial Tree The trachea divides into two primary bronchi 1. The right primary bronchus is wider, shorter and more vertical. A foreign body in the trachea more frequently falls into the right bronchus. It divides into 3 secondary (lobar) bronchi 2. The Left primary bronchus is narrower, longer and more horizontal. It divides into 2 secondary (lobar) bronchi 3. The Secondary (lobar) bronchi for each lobe of the lung, then divide into 4. Tertiary (segmental) bronchi for each segment of the lobe. There are ten in each lung. It divide successively into bronchioles -- terminal bronchioles -- respiratory bronchioles -- alveolar ducts -- alveolar sacs. A diseased segment can be removed surgically without affecting the rest of the lung. With successive branching of the bronchial tree amount of cartilage decreases and amount of smooth muscle increases, this allows for variation in airway diameter. 6 Alveoli The alveoli are thinwalled air sacs lined by simple squamous epithelium surrounded by network of capillaries, specialized for diffusion of gases. 7 The Lungs LOCATION: The lungs are suspended in their pleural cavities in the thorax and are attached to the mediastinum only by their roots SHAPE: Lungs are cone shaped with the apex upwards into the neck and the base resting on the diaphragm. 8 The Lungs Hilum: a slit through which the lung receives the main bronchus, blood vessels, lymphatics, and nerves. These structures constitute the root of the lung. Root: (from anterior to posterior): pulmonary veins then pulmonary artery and then the bronchus. On right side there are two bronchus. 9 The Lungs Right lung It is shorter than left lung because of the liver on the right. It has three lobes: superior, middle, and inferior It is separated by horizontal and oblique fissures 10 The Lungs Left lung It is taller and narrower because the heart is tilted toward the left Anteriorly, it has a large depression called as cardiac notch. A single oblique fissure divides it into superior and inferior lobes. The lower part of the upper lobe is extended and shaped like a tongue, called as (Lingula) that projects over the heart. Superior Middle Inferior Superior Inferior 11 Oblique horizontal Oblique Blood Supply to the Lung Pulmonary circulation (only to alveolar areas of bronchopulmonary tree called as respiratory zone): The pulmonary arteries transfer the deoxygenated blood from the heart to the lungs, one on each side. The pulmonary veins transport oxygenated blood from the alveoli of the lungs to the left atrium of heart through two veins on each side. Bronchial circulation (to all non-alveolar parts of the bronchopulmonary tree called as conducting zone): Bronchial arteries supply oxygenated blood arises arise as branches of two sources; thoracic aorta and upper aortic intercostal arteries. Bronchial veins carry deoxygenated blood away from lung tissue through azygos vein into the superior vena cava. 12 THORACIC WALL 1. THORACIC BONES: 1. 12 Thoracic vertebrae 2. 12 ribs 1. 1-7 true ribs 2. 8-10 false ribs 3. 11-12 floating ribs. Three layers of flat muscles fill the intercostal spaces: 1. External intercostal 2. Internal intercostal 3. Innermost intercostal 13 Thorax wall It is a part of trunk between neck and abdomen. It consists of: the thoracic wall, the mediastinum and two pleural cavities The thoracic a wall Protects the heart and lungs, Support for the upper limbs, Assist in respiration. It is formed by: Posteriorly: 12 thoracic vertebrae and their intervertebral discs Laterally: 12 pairs of ribs Anteriorly: the sternum and costal cartilages Superior & Inferior Thoracic Apertures (Inlets) The superior thoracic aperture / thoracic inlet Acts as conduit for the structures passing between thorax, neck and upper limb. Its boundaries are: Posterior: T1 vertebra Lateral: medial margin of 1st rib Anterior: manubrium The inferior thoracic aperture / thoracic outlet It is large and expandable. It is closed by the diaphragm It is bounded: Posteriorly: body of T12 vertebra Postero-laterally: 12th and 11th ribs Antero-laterally: costal margins Anteriorly: xiphoid process Diaphragm The diaphragm is a dome shaped musculo-tendinous partition between thoracic cavity and abdominal cavity. It has two parts central and peripheral. PARTS OF DIAPHRAGM: – a- central tendinous and b- peripheral muscular part. ATTACHMENTS: – Peripheral part: Sternal, costal, medial and lateral arcuate ligaments and right and left crus. – Central part: Central part is tendinous and merge together in the center and provide a seat for heart. 16 Openings in the Diaphragm Aortic opening is present at the level of 12th thoracic vertebra. Esophageal opening is present at the level of 10th thoracic vertebra. It transmits the aorta. It transmits the esophagus Abdominal view Caval opening is present at the level of 8th thoracic vertebra. It transmits the inferior vena cava (IVC) Thoracic view 17 Nerve Supply of the Diaphragm Motor: The right and left phrenic nerves (C3-C5) Sensory: the central part of the diaphragm is supplied from the phrenic nerve (C3-C5) and the peripheral part from the lower six intercostal nerves (T7-T12) 18 19