Heart, Blood Vessels and Circulation

• Generating blood pressure


  Required for blood flow through the blood vessels
• Routing blood


  Two pumps, moving blood through the pulmonary and systemic circulations
• Regulating blood supply


  Adjusts blood flow by changing the rate and force of heart contractions as needed
• Functions of the heart

  • Generating blood pressure
  • Routing blood
  • Regulating blood supply
• Pulmonary circulation


  The flow of blood from the heart through the lungs back to the heart. Picks up oxygen and releases carbon dioxide in the lungs.
• Systemic circulation


  The flow of blood from the heart through the body back to the heart. Delivers oxygen and picks up carbon dioxide in the body's tissues.
• The heart is located anterior to the vertebral column, posterior to the sternum - in the mediastinum, a mass of tissue in the center of the thorax containing important thoracic internal organs
• The apex of the heart points at your left ASIS (Anterior Superior Iliac Spine)
• Approximately 2/3 of the mass of the heart lies left on the body's midline
• Orientation of the apex of the heart

  Anterior, Inferior, towards the left
• Orientation of the base of the heart

  Posterior, Superior, towards the right
• Dextrocardia


  A congenital anomaly in which the heart is on the right side of the thoracic cavity, may be associated with the reversal of all abdominal organs (situs inversus)
• Apex beat


  In adults, felt in the left 5th intercostal space 9cm from the median plane (just medial to the midclavicular line). In infants, felt in the 3rd intercostal space just lateral to the midclavicular line.
• Each atrium has a flap called an auricle to increase the SA of the atria
• The coronary sulcus (shallow grooves) separates the atria from the ventricles
• The interventricular grooves separate the right and left ventricles
• Layers of the heart

  • Pericardium
  • Epicardium
  • Myocardium
  • Endocardium
• Pericardium


  A double-walled sac around the heart composed of a superficial fibrous pericardium and a deep two-layer serous pericardium
• Epicardium


  Visceral layer of the serous pericardium, provides protection against friction of rubbing organs
• Myocardium


  Cardiac muscle layer forming the bulk of the heart, responsible for contraction
• Endocardium


  Endothelial layer over connective tissue, reduces friction from blood flow
• Pericarditis


  Inflammation of the serous pericardium, can cause painful sensations and fluid accumulation
• Cardiac tamponade


  Potentially fatal condition where fluid/blood accumulates in the pericardial cavity and compresses the heart, preventing it from filling with blood
• Endocarditis


  Inflammation of the endocardium, affects the valves more severely and can lead to scarring and stenosis
• Cardiomyopathy


  Disease of the myocardium, results in weakened cardiac muscle and enlarged heart chambers, can lead to congestive heart failure
• Rheumatic heart disease


  Results from a streptococcal infection in young people, toxin can cause rheumatic fever and rheumatic endocarditis
• Right atrium


  Receives deoxygenated blood, has openings for superior vena cava, inferior vena cava, and coronary sinus
• Left atrium


  Receives oxygenated blood from the lungs, has openings for the 2 right and 2 left pulmonary veins
• Tricuspid valve


  3 cusps/leaflets, allows blood flow from right atrium to right ventricle
• Bicuspid/mitral valve


  2 cusps/leaflets, allows blood flow from left atrium to left ventricle
• The fossa ovalis is a remnant of the foramen ovale in the interatrial septum
• Right ventricle


  Has papillary muscles, trabeculae carneae, and chordae tendineae. Wall is less thick than the left ventricle.
• Left ventricle


  Has trabeculae carneae and chordae tendineae. Wall is thicker than the right ventricle and has a smaller lumen diameter.
• The pulmonary trunk exits the right ventricle carrying blood to the pulmonary circulation, while the aorta exits the left ventricle carrying blood to the systemic circulation
• The ductus arteriosus (ligamentum arteriosum) is present at birth
• Heart valves


  • Atrioventricular valves: Tricuspid, Bicuspid/Mitral
  • Semilunar valves: Pulmonary, Aortic
• Heart sounds


  • Lubb (S1) - closure of AV valves
  • Dupp (S2) - closure of semilunar valves
  • S3 - rapid ventricular filling
  • S4 - atrial contraction
• The fibrous skeleton of the heart provides a structural foundation, prevents valve overstretching, and acts as an electrical insulator between the atria and ventricles
• Septal defect


  Hole in the septum between the left and right sides of the heart, allowing blood flow between sides and reducing pumping effectiveness
• Patent ductus arteriosus


  Ductus arteriosus fails to close after birth, allowing blood flow from the aorta to the pulmonary trunk under higher pressure