Thorax and Heart Anatomy PDF

THORAX The thorax consists of: the thoracic cage the 2 pleural cavities surrounding the lungs the area between (medial to) these cavities, THE MEDIASTINUM (heart, great vessels, trachea, esophagus, vagus& phrenic nerve, thymus, and the thoracic duct). The Mediastinum Med...

THORAX The thorax consists of: the thoracic cage the 2 pleural cavities surrounding the lungs the area between (medial to) these cavities, THE MEDIASTINUM (heart, great vessels, trachea, esophagus, vagus& phrenic nerve, thymus, and the thoracic duct). The Mediastinum Median region of thorax Extending from the sternum anteriorly to the vertebral column posteriorly & from the thoracic inlet superiorly to the diaphragm inferiorly HEART ❖ Within the anterior part of the mediastinum ❖ Approximately the size of your fist Location ❖ Superior surface of diaphragm ❖ Left of the midline ❖ Anterior to the vertebral column, posterior to the sternum, medial to the lungs PERICARDIUM Protective membrane structure that surrounds the heart Two principal parts: Fibrous pericardium –tough, dense irregular connective tissue and prevents overstretching and anchors heart Serous pericardium –delicate, double layer serous membranes with serous fluid in thin cavity between membraneS  HEART WALL Epicardium ->Superficial, visceral layer of the Pericardium ->Contains blood and lymphatic vessels that supply the heart muscle Myocardium->Middle, cardiac muscle tissue layer Endocardium->Endothelium layer overlying connective tissue ->Lines heart chambers, heart valves ->Continuous with endothelial lining blood vessels ->Fibrous skeleton of the heart that isolates the atria and ventricles while supporting the valves SURFACE ANATOMY OF THE HEART Coronary sulcus:divides atria and ventricles Anterior and posterior interventricular sulcus: separates left and right ventricles contain blood vessels of cardiac muscle RIGHT ATRIUM (BLU, deoxygenated blood) Forms the entire right border of the heart Receives blood from the systemic circulation via the superior and inferior vena cava Separated internally from left atrium by interatrial septum, that contains the fossa ovalis (remnant of fetal foramen ovale linking the atria) Smooth posterior wall, but pectinate muscle ridges anteriorly extending into auricle Crista terminalis(demarcates between rough and smooth walled surfaces) location of SA node Blood passes through the tricuspid valve (right atrioventricular valve) into right ventricle RIGHT VENTRICLE Receives blood from the right atrium Separated internally from the left ventricle by interventricular septum Interior of chamber has ridges, raised bundles of cardiac muscle called trabeculae carneae Cusps of tricuspid valve connected to structures in ventricle chamber Chordae tendineae –tendon-like cords attached to... Papillary muscles –cone-shaped trabeculae carneae These prevent backflow in systole Pumps blood through the pulmonary valve (semi-lunar valve) into the pulmonary trunk that carries blood to the lung. LEFT ATRIUM (RED, OXYGENATED BLOOD) Base of the heart Posterior wall of the left atrium receive the 4 pulmonary veins that carry oxygenated blood from the pulmonary circulation Same arrangement of pectinate muscles Blood passes through the bicuspid or mitral valve (left atrioventricular valve) into the left ventricle Interatrial septum separates right atrium from left LEFT VENTRICLE Forms the apex of the heart Receives blood from left atrium Papillary muscles & Chordae tendineae-anchor the bicuspid (AV) valve cusps and prevent backflow of blood Necessarily thick, muscular myocardium larger than the right ventricle. Pumps blood through the aortic valve (semi-lunar valve) into the ascending aorta that carries blood to the heart wall and to the rest of the body Vessels returning blood to the heart: Superior and inferior venae cavae Coronary sinus, with contributions from the great, middle, small and posterior cardiac veins Right and left pulmonary veins (oxygenised) Vessels conveying blood away from the heart include: Pulmonary trunk, which splits into right and left pulmonary arteries (de-oxygenised) Ascending aorta (three branches) –brachiocephalic, left common carotid and subclavian arteries Systemic circulation →right atrium→ tricuspid valve→ right ventricle Right ventricle→pulmonary semilunar valve→pulmonary arteries →lungs Lungs→ pulmonary veins→left atrium Left atrium→bicuspid valve→left ventricle Left ventricle→aortic semilunar valve→aorta Aorta→systemic circulation pulmonary circulation CORONARY CIRCULATION Coronary circulation is the functional blood supply to the heart muscle itself Collateral routes ensure blood delivery to heart even if major vessels are occluded (anastomoses–connections formed where two or more arteries provide alternate routes in case of obstruction) Coronary arteries Right coronary artery springs from the right anterior aortic sinus Left coronary artery springs from the left anterior aortic sinus They run in the interventricular sulcus and the coronary sulcus CARDIAC VEINS Carry deoxygenated blood from the heart to the right atrium Coronary sinus, the largest opening, occupies the post part of the coronary sulcus Draining into the coronary sinus are the great cardiac vein, middle cardiac vein,small cardiac vein and the posterior cardiac vein Anterior cardiac veins drain directly into the right atriumCardiac veins Nervous supply of the heart All organs within the body are supplied by the autonomic nervous system  ANS is divided into 2 systems:1. Parasympathetic system 2. Sympathetic system DISEASES OF THE HEART Coronary artery disease (CAD)-> atherosclerosis- accumulation of fatty deposits in the inner lining of the arteries ( symptoms-> thoracic pain and muscle cell are weakened) Myocardial infarction (MI)-> heart attack, most commonly due to CAD, ischemic (decreased blood supply) tissue degenerates ( lack of oxygen causes tissue death) Coronary artery occlusion Ventricular septal defect Atrial septal defect FETAL SHUNTS Two fetal conduits that bypass the pulmonary circulation while the lungs are developing: foramen ovalis and ductus arteriosum. The fetus obtains its oxygen from the placenta at this time. Foramen ovalis allows passage of oxygenated blood from the right to left atria. When the lungs become functional at birth the foramen closes. The fosse ovale in the atrial septum is remnant. When the foramen does not close it is called a patent foramen ovale(PFO) and may be present in up to 20% of adults. Patent Ductus Arteriosus Irregular transmission of blood between the aorta and the pulmonary arteries Once closed, known as the ligamentum arteriosum  CARDIOPULMONARY SYSTEM Flow and regulation of blood between the heart and lungs Main connection is pulmonary arteries and veins Closely associated with the cardiovascular system and cardiorespiratory system Consists of the HEART (cardiovascular), LUNGS (pulmonary), and ARTERIES, VEINS, CORONARY and PORTAL VESSELS (systemic) THORACIC CAVITY Irregular shaped cylinder Narrow superior opening Wide inferior opening Divided into 3 compartments: Left and right pleural cavity (surrounding each lung) Mediastinum (containing the heart) SURFACE ANATOMY Anterior–jugular notch, sternal angle, xiphoid process, clavicle Lateral –12 ribs and costal cartilage, costal margin Posterior–vertebrae,12 ribs, scapula T IV/V Horizontal plane Location of rib II Arch of aorta begins and ends Level where the trachea bifurcates into right and left main bronchi Components of Thorax  Thoracic wall Superior and Inferior thoracic aperture Diaphragm Mediastinum Pleural cavities Functions of the thoracic cage: Breathing –holds lungs, diaphragm, thoracic wall and ribs Protection –houses and protects heart, lungs and the great vessels provides protection to most of the liver, stomach, superior part of the kidneys Conduit –structures pass through the mediastinum on their way to other body regions, e.g.esophagus Thoracic wall Anterior–sternum Lateral–12 ribs, 3 layers of flat muscles, intercostal spaces Posterior–12 thoracic vertebrae & intervertebral discs Relations to other regions Neck–superior aperture opens into the root of neck Upper limb–axillary inlet lies on the side of the superior opening Abdomen–Diaphragm separates the thorax from the abdomen Breast–lie either side of anterior thoracic wall Planes of Thorax Midclavicular line Midaxillary line Pleural cavities & Lungs Two pleural cavities (either side of the mediastinum) Two lungs –organs of respiration Right lung is usually larger as the heart lies to the left side of the mediastinum Mediastinum Midline partition containing the pericardium, heart, great vessels, esophagus Anterior Posterior Anterior Posterior  CPR Cardiopulmonary resuscitation emergency procedure to stimulate both the heart and the lung function, when the heart stops suddenly Combination of external heart massage and artificial respiration Cardiopulmonary Disease Cardiovascular disease (CVD) is a general term for conditions affecting the heart or blood vessels Chronic Obstructive Pulmonary Disorder (COPD) is a chronic inflammatory lung disease that causes obstructed airflow from the lungs