Heart and Pericardium PDF

Mediastinum Space between two pleural cavities Extent Superiorly : Thoracic outlet(root of neck) Inferiorly : Diaphragm Anteriorly : Sternum Posteriorly: Vertebral coloumn Divisions Superior mediastinum Aortic arch & its branches (brachiocephalic,left common carotid,left subclavian) Veins: SVC, br...

Mediastinum Space between two pleural cavities Extent Superiorly : Thoracic outlet(root of neck) Inferiorly : Diaphragm Anteriorly : Sternum Posteriorly: Vertebral coloumn Divisions Superior mediastinum Aortic arch & its branches (brachiocephalic,left common carotid,left subclavian) Veins: SVC, brachiocephalic vein Nerves: Vagus,phrenic ,left recurrent laryngeal  Inferior Mediatinum Anterior mediastinum: loose connective tissue Middle mediastinum: Pericardium & heart Posterior mediastinum: Descending aorta Azygous,hemiazygous vein Vagus nerve Esophagus,thoracic duct Heart HEART Heart is a four chambered, hollow muscular organ approximately the size of your fist. Location: – Superior surface of diaphragm – Left of the midline – Anterior to the vertebral column, posterior to the sternum Pericardium  Heart Wall Three layers of tissue – Epicardium: This is the visceral pericardium – Myocardium: Middle layer composed of cardiac muscle cell and responsibility for heart contracting – Endocardium: this is the inner surface of heart chambers External Anatomy Four chambers –2 atria –2 ventricles Major veins –Superior & inferior vena cava –Pulmonary veins Major arteries –Aorta –Pulmonary trunk Surfaces  Heart – Internal features Atria - Right Left Ventricles – Right Left Valves – Atrio-ventricular Semilunar Atria of the Heart Atria are the receiving chambers of the heart Blood enters right atrium from superior and inferior venae cava Blood enters left atrium from pulmonary veins Each atrium has a protruding auricle Pectinate muscles mark atrial walls Right atrium Parts of right atrium Sinus venerum Posterior smooth part Openings: SVC IVC Opening of coronary sinus Anterior rough part Crista terminalis Musculi pectinati  Interatrial septum Separates right & left atrium Fossa ovalis Limbus fossa ovalis Pectinate muscles Papillary muscles and trabeculae carneae Left atrium 4 pulmonary veins Left atrioventricular orifice  Ventricles of the Heart Ventricles are the discharging chambers of the heart Right ventricle pumps blood into the pulmonary trunk Left ventricle pumps blood into the aorta Papillary muscles and trabeculae carneae muscles mark ventricular walls  Myocardial Thickness and Function – Thickness of myocardium varies according to the function of the chamber. – Atria are thin walled, deliver blood to adjacent ventricles. – Ventricle walls are much thicker and stronger – right ventricle supplies blood to the lungs (little flow resistance) – left ventricle wall is the thickest to supply systemic circulation Heart Valves Heart valves ensure unidirectional blood flow through the heart Atrio-ventricular (AV) valves lie between the atria and the ventricles – AV valves prevent backflow into the atria when ventricles contract Chordae tendineae anchor AV valves to papillary muscles  Semilunar valves prevent backflow of blood into the ventricles Aortic semilunar valve lies between the left ventricle and the aorta Pulmonary semilunar valve lies between the right ventricle and pulmonary trunk Coronary Circulation: Arterial Supply Coronary Circulation: Venous Supply