Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
The Thoracic Cavity Boundaries of and Structures Within Cavities • Dorsal body cavity • Ventral body cavity – Abdominopelvic • Abdominal • Pelvic – Divided by Diaphragm – Thoracic • 2 Pleural • Mediastinum www.newworldencyclopedia.org Serous membrane = Serosa • Simple squamous epithelium + areolar connective tissue • 2 Layers – Outer layer = PARIETAL serosa – Inner layer = VISCERAL serosa • Between them = Serous Cavity containing Serous Fluid – Serous fluid is blood filtrate + secretions by 2 layers of membrane – Allows movement of organs with reduced friction • Types of Serous Membranes – Pleural = surrounds lungs – Pericardium = surrounds heart, slightly modified – Peritoneal = surrounds some abdominal organs Pleural Cavities • Surround the lungs • Pleural fluid secreted by pleural membranes • Holds layers together • Reduces friction of organs • Compartmentalization pg 136 Pleural Cavities • 2 Layers – Parietal pleura (outer) • inner surface of thoracic wall • superior surface of diaphragm • lateral surface of mediastinum – Visceral pleura (inner) • root of lungs marks transition • external surface of lungs pg 137 Pleural Abnormalities www.rcjournal.com • Pleural Effusion – Excess fluid in the pleural cavity – More than 20X • Usually less than 1 ml of fluid • Pneumothorax – Air located in pleural space Pg 210 www.islamicboard.com Divisions of Mediastinum •Superior (to heart) •Contains: thymus, cranial vena cava, trachea, esophagus •Inferior •Anterior (to heart) •Contains: thymus •Posterior (to heart) •Contains: aorta, esophagus, trachea, bronchi, caudal vena cava •Middle •Contains: heart pg 153 Boundaries of Mediastinum • Lateral – parietal pleura of lungs • Anterior – ventral parietal pleura • Posterior – dorsal parietal pleura • Superior – dome of the neck • Inferior – diaphragmatic pleura pg 136 Respiratory Tract • Upper Respiratory Tract – Superior to Larynx • Lower Respiratory Tract – – – – – – Larynx Trachea Primary Bronchi Secondary Bronchi Rest of Bronchial Tree Lungs pg 944 Trachea = windpipe • • • • • • Starts at Larynx and travels through mediastinum Located Anterior to Esophagus Trachea terminates into 2 primary bronchi entering lungs Walls contain 16-20 “C” shaped rings Hyaline Cartilage Trachealis Muscle (smooth muscle and soft CT) Layers (deep to superficial) – Mucosa = Ciliated Psuedostratified Epithelium – Submucosa- contains seromucous glands – Adventitia – made of connective tissue, contains cartilage rings Pg 917 Bronchial Tree • Primary (main) Bronchi – – – – – Bifurcation of trachea Basically the same structure Cartilage plates replace rings Posterior to pulmonary vessels Right is wider, vertical, shorter • Secondary (lobar) Bronchi – Each primary bronchi divides – Same structure as primary bronchi – Right lung has 3, Left has 2 • Tertiary (segmental) Bronchi • Up to 23 divisions pg 145 Bronchial Tree (continued) • Bronchioles – further divisions, < 1 mm diameter • Terminal Bronchioles – further divisions, 0.5 mm diameter • Respiratory Zone – Respiratory Bronchioles – Alveolar Ducts – Alveolar Sacs • Terminal bunches of Alveoli • Respiratory exchange chamber Respiratory Zone (continued) • Lining the Walls of Alveoli – Respiratory Membrane • Type I cells = simple squamous epithelial cells • Basal lamina and fine areolar CT • Covered with capillaries and elastic fibers – Gas exchange • Oxygen into blood • Carbon Dioxide into alveoli – Type II cells = cuboidal epithelial cells • Secrete fluid containing surfactant Throughout Bronchial Tree • Psuedostratified columnar changes to simple columnar to simple cuboidal • Cartilage rings replaced by cartilage plates once bronchi enter the lungs • Smooth muscle and Elastic fibers remain important • In Bronchioles – Ciliated mucosa disappears, replaced by macrophages in alveoli – Cartilage disappears – Smooth muscle forms bands around smallest bronchi and bronchioles (not found around alveoli) LUNGS (continued) • Located in Pleural Compartments • Lateral to Mediastinum • Location – Apex posterior to clavicle – Base lays on Diaphragm – Costal Surface = Ant, Lat, Post surfaces contact ribs • Left Lung = 2 lobes – – – – Upper Lower Oblique Fissure Cardiac Notch • Right Lung = 3 lobes – – – – – Upper Middle Lower Oblique fissure Horizontal fissure pg 145 LUNGS • Hilus- medial indentation • Root of Lung = structures enter each lung – 2 Pulmonary Veins = carries O2-rich blood from each lung to heart – 1 Pulmonary Artery = carries O2-poor blood to each lung – Primary Bronchus – Nerves – Lymph Vessels pg 141 Specific Location of Lungs • Right Lung – – – – – – 1” above Rib 1 Crosses Costal Cartilage 6 Midclavicular at Rib 6 Midaxillary at Rib 8 Vertebral Border at Rib 10 Inferior border 2 rib widths above diaphragm • Left Lung – 1” above Rib 1 – Deep to Manubroclavicular joint – Midsternally to Rib 4 – Jogs to left, continues to Rib 6 – Midaxillary Rib 8 – Vertebral Border at Rib 10 Lung Lobes • Lobes are anatomically + functionally separate • Lung lobes divided into Lobules – Functionally separate – Separated by dense CT – Vary in size • Stroma = lung tissue – CT – Many elastic fibers pg 155 Esophagus • Esophagus – Pharynx to Stomach – Passes thru diaphragm at esophageal hiatus – Anterior to vertebrae, Posterior to trachea • Layers of Esophagus (deep to superficial) – Mucosa • Stratified squamous epithelium • Lamina propria (loose CT) • Muscularis mucosae – Submucosa • Loose connective tissue • Secretes mucus – Muscularis Externa • Circular/Longitudinal layers • Skeletal m, Mix, then Smooth m – Adventitia • Fibrous CT pg 139 The Diaphragm • • • • Skeletal Muscle Dome-shaped (relaxed) Flattens (contracts) Divides thoracic & abdominopelvic cavities • Attachments – O: Inferior Internal rib cage, Lumbar vertebrae (by crura) – I: Central tendon • Innervated by right + left PHRENIC Nerves pg 114 Action of the Diaphragm • Primary muscle of respiration (involuntary) – Contraction during inspiration • Increases volume of thoracic cavity • Decreases pressure of thoracic cavity • Air moves into lungs (highlow pressure) • Forced contraction (voluntary) – Used for defecation, urination, labor • Decreases volume of abdominal cavity • Increases pressure in abdominal cavity • Pushes on abdominal organs to move contents out pg 114 Thoracic Cavity Capacity is Increased by: • Contraction of diaphragm • Intercostal muscles elevate ribs • Rib elevation causes the sternum to move anteriorly pg 113 Openings of Diaphragm • PosteriorAnterior • Aortic Hiatus – Aorta – Azygos vein – Thoracic duct • Esophageal Hiatus – Esophagus – Vagus nerve • Caval Opening – Inferior Vena Cava – Right Phrenic Nerves pg 134 Vena Cava • Superior Vena Cava – in Superior mediastinum, right side – Receives blood from regions above diaphragm – Formed from Rt + Lft Brachiocephalic Veins cranially – Azygos Vein empties into it just superior to heart – Empties into Right Atrium • Inferior Vena Cava – in Inferior mediastinum (right side), runs through abdomen – Returns blood to heart from regions below diaphragm – Formed from Rt + Lft Common Iliac Veins – Empties into Right Atrium – Widest blood vessel in body Veins of Thoracic Cavity • Vena Cavae • Azygos Vein – “unpaired” – right side of vertebral bodies (at level of T12) – runs superiorly – empties into Sup. Vena Cava – drains right posterior intercostal veins – Connects to hemiazygos and accessory hemiazygos that drain left side pg 131 The Lymphatic Vessels • Function: to collect excess tissue fluid collecting at arteriole end of capillary beds, and return leaked blood proteins to blood (maintain osmotic pressure needed to take up water into bloodstream) • Lymph is moved through vessels – – – – Pulse of nearby arteries Contraction of surrounding skeletal muscle Regular movement of body (wiggling legs) Muscle in Tunica Media • Lacteals-lymphatic capillaries w/unique function – In mucosa of small intestine, receive digested fat from intestine – Fatty lymph becomes milky = Chyle – Chyle goes to bloodstream Lymphatic System…The Players: • Lymph- clear fluid from loose CT at capillaries – Contains small molecules of blood plasma, water, various ions, nutrient molecules, respiratory gases • Lymphatic capillaries (near blood capillaries) • Lymph collecting vessels (small, 3 tunicas, # valves) • Lymph nodes (sit along collecting vessels)-clean lymph of pathogens, they are NOT glands • Lymphatic trunks (convergence large collecting vessels) • Lymphatic ducts empty into veins of neck Lymphatic Ducts • Thoracic Duct – Receives lymph from large trunks in abdomen and thorax – Receives lymph from ducts of thoracic lymph nodes – Along vertebral bodies – Contain valves to ensure 1way flow of lymph to lymph nodes – Drains into left Brachiocephalic Vein (or subclavian or int. jugular veins) pg 132, 150 Thymus Gland • Lymphatic Organ • 2-lobed w/lobules • Sits on heart and great vessels • Immature lymphocytes mature into T-lymphocytes • Secretes Thymic Hormones: help T-lymphocytes gain immunocompetence • Decreases in size w/age • Functional tissue is replaced with fatty tissue pg 183 Thymus Gland • Increases in size during childhood • Decreases in size during adulthood • Contains lobes and lobules – Capsule – Cortex – Medulla