HEMOTOLOGY

• Heart is a muscular organ that pumps blood throughout the body, located in the middle cavity of the chest between the lungs
• Heart surfaces: sternocostal or anterior surface, diaphragmatic or inferior surface, pulmonary or left surface
• The heart rests on the diaphragm, near the midline of the thoracic cavity, in the mediastinum
• Heart structure: pointed apex formed by the tip of the left ventricle, base formed by the atria
• Hemodynamics describe the intravascular pressure and flow when the heart contracts and pumps blood throughout the body
• Dimensions of the heart: about 12 cm long, 9 cm wide, 6 cm thick, with an average mass of 250 g in adult females and 300 g in adult males
• Sulci of the Heart: grooves marking division between atria and ventricles - Atrioventricular sulcus, Anterior interventricular sulcus, Posterior interventricular sulcus
• Heart


  • Composed of smooth muscle
  • Has four chambers
  • Hollow, cone-shaped, muscular pump
  • Beats about 2.5 billion times in an average lifetime
  • Left side pumps blood through an estimated 120,000 km of blood vessels
  • Right side pumps blood through the lungs, enabling oxygen pickup and carbon dioxide unloading
  • Pumps more than about 14,000 liters of blood in a day or 5 million liters in a year
• Relations of Heart

  • Superiorly - aorta, superior vena cava, Pulmonary artery, and pulmonary vein
  • Inferiorly - diaphragm
  • Anteriorly - ribs and intercostal muscles
  • Posteriorly - esophagus, trachea, left and right bronchus, descending aorta, inferior vena cava, thoracic vertebrae
  • Laterally - lungs
• Hemodynamics


  Forces circulating blood through the body
• Heart borders: right border formed by the right atrium, inferior border by the right ventricle and partly the left ventricle, left border by the left ventricle and left auricle, superior border by both atria
• Pericardial fluid: A slippery fluid is present in between the parietal and visceral layers to give lubrication and reduce friction while the heart beats
• The heart is enclosed in a double-walled sac called the pericardium
• Pericardial Sinuses


  • The transverse pericardial sinus lies anterior to the superior vena cava and posterior to the ascending aorta and pulmonary trunk
  • The oblique pericardial sinus lies posterior to the heart in the pericardial sac
• Anterior interventricular sulcus


  Lies between the left ventricle and right ventricle on the anterior surface, marks the location of interventricular septum containing left anterior descending artery, great cardiac vein
• Pericardial Sinuses: The lines of reflection between visceral and parietal pericardium form two pericardial sinuses
• Parts of the pericardium

  • The serous pericardium (Parietal – superior; Visceral – inferior)
  • The fibrous pericardium - composed of tough, inelastic, dense irregular connective tissue
• The right atrium and left atrium are separated by the fossa ovalis
• The wall of the heart consists of three layers: epicardium (external layer), myocardium (middle layer), endocardium (inner layer)
• The right atrium forms the right border of the heart and receives blood from three veins: the superior vena cava, inferior vena cava, and coronary sinus. The right atrium is about 2–3 mm in thickness
• Auricle


  The anterior surface of each atrium is a wrinkled pouch-like structure called an auricle. Each auricle slightly increases the capacity of an atrium so that it can hold a greater volume of blood
• Fibrous pericardium


  Prevents overstretching of the heart, protects the heart, anchors the heart in the mediastinum
• Posterior interventricular sulcus


  Lies between the left ventricle and right ventricle on the posterior surface, contains posterior interventricular artery and middle cardiac vein
• Interatrial septum is a prominent feature separating the right atrium and left atrium
• The heart has four chambers: two superior receiving chambers (atria) and two inferior pumping chambers (ventricles)
• Tricuspid valve

  • Cusps connected to chordae tendineae which are connected to papillary muscles
• Mitral or bicuspid valve


  • Consists of two cusps, anterior cusp is larger, chordae tendineae attach the cusps to papillary muscles
• Left atrium


  • About the same thickness as the right atrium, receives blood from the lungs through four pulmonary veins, has a smooth anterior and posterior wall
• Blood flowing into the coronary arteries

  Branching from the ascending aorta and carrying blood to the heart wall
• Pulmonary valve


  • Consists of three semilunar cusps, lower margins and sides attached to the arterial wall
• Blood passing from the left atrium to the left ventricle

  Through the bicuspid (mitral) valve
• Right atrium and left atrium

  • Separated by the fossa ovalis
• Right ventricle

  • About 4–5 mm in average thickness, contains trabeculae carneae, separated from the left ventricle by the interventricular septum
• Remaining blood passing into the arch of the aorta and descending aorta

  Branches carry blood throughout the body
• Interatrial septum

  • A prominent feature is an oval depression
• Blood passing from the right atrium to the right ventricle

  Through the tricuspid valve consisting of three leaflets or cusps
• Blood passing from the right ventricle through the pulmonary valve


  Into the pulmonary trunk, which divides into right and left pulmonary arteries
• Tricuspid valve

  • Consists of three cusps, bases attach to the fibrous ring of the heart skeleton, free edges attach to chordae tendineae connecting them to papillary muscles
• Left ventricle

  • The thickest chamber of the heart, contains trabeculae carneae and chordae tendineae, blood passes through the aortic valve into the ascending aorta
• Right side of the heart

  Deoxygenated blood from the body (to lungs)