Heart

• The heart has four chambers: two atria and two ventricles
• Atriums are thin-walled chambers that receive blood from veins and pump it into ventricles
• The heart is located between the lungs, behind the sternum (breastbone), and to the left side of the body.
• The heart is a muscular organ located slightly to the left of the middle of the chest.
• The heart has valves that prevent backflow of blood between chambers or out of the heart altogether.
• Ventricles are thicker walled than the atria, they contract to push blood out of the heart through arteries
• The right atrium receives deoxygenated blood returning from the body through the superior vena cava and inferior vena cava.
• The right ventricle pumps oxygen-poor blood out through the pulmonary artery to the lungs.
• The right ventricle pumps oxygen-poor blood out of the heart via the pulmonary artery to the lungs.
• The left atrium receives oxygenated blood from the pulmonary vein and pumps it into the left ventricle.
• The right atrium receives deoxygenated blood from the vena cavae and pumps it into the right ventricle
• The right ventricle pumps oxygen poor blood to the lungs via pulmonary trunk
• The left atrium receives oxygenated blood returned from the lungs through the pulmonary vein.
• The left atrium receives oxygen rich blood from the lungs and pumps it into the left ventricle
• The right ventricle pumps oxygen-poor blood to the lungs via pulmonary trunk.
• The left atrium receives oxygenated blood coming from the lungs through four pulmonary veins.
• The left ventricle pumps oxygenated blood to all parts of the body except the lungs via aorta.
• The left atrium receives oxygenated blood coming into it from the four pulmonary veins.
• The left ventricle pumps oxygenated blood out through the aorta to all parts of the body except the lungs.
• Blood flows from the right atrium to the right ventricle through the tricuspid valve.
• Blood flows from the right side of the heart (right atrium -> right ventricle) to the lungs where it picks up oxygen and returns to the left side of the heart (left atrium -> left ventricle). From there, it's pumped out to the rest of the body.
• The heart


  A muscular organ that pumps blood through the body
• The cardiovascular system


  • Includes the heart, blood vessels, and blood
  • A healthy adult heart pumps about 5 liters of blood per minute at rest
  • This rate can be maintained for over 75 years
• The heart


  • Comprises two pumps: the right side pumps blood to the lungs, the left side to the body tissues
  • There are two circulations: pulmonary (to the lungs) and systemic (to body tissues)
• Functions of the heart

  • Generates blood pressure
  • Routes blood
  • Ensures one-way blood flow
  • Regulates blood supply
• The heart


  • Size: about the size of a fist, weighing less than 1 lb
  • Location: between the lungs in the thoracic cavity
  • Orientation: apex towards the left side
• Pericardia


  • Double-layered sac anchoring and protecting the heart
  • Parietal pericardium: membrane around the heart's cavity
  • Visceral pericardium: membrane on the heart's surface
  • Pericardial cavity: space around the heart
• Heart external anatomy


  • Coronary sulcus separates atria from ventricles
  • Sulci divide right and left ventricles
  • Grooves indicate heart's surface divisions
  • Major vessels: superior and inferior vena cava, pulmonary trunk, aorta
• Surface anatomy of the heart is illustrated
• Heart chambers


  • Four chambers: left and right atria, left and right ventricles
  • Coronary sulcus separates atria from ventricles
• Atria


  Receive blood, thin-walled, contract minimally
• Ventricles


  Pump blood, thick-walled, contract forcefully
• Heart valves


  • Atrioventricular (AV) valves: tricuspid (right) and bicuspid/mitral (left)
  • Semilunar valves: pulmonary and aortic
• Control of heart valves


  • Papillary muscles and chordae tendineae prevent valve regurgitation
• Internal anatomy of the heart is illustrated, showing chambers and valves
• Cardiac skeleton


  Fibrous rings surrounding valves, providing support and electrical insulation
• Blood supply to the heart


  • Coronary arteries supply blood to heart wall
  • Cardiac veins drain blood from cardiac muscle
• Heart wall


  • Epicardium (outer)
  • Myocardium (middle)
  • Endocardium (inner)
• Cardiac muscle

  • Characteristics and structure of cardiac muscle cells
• Stimulation of the heart


  Sequence of events leading to atrial and ventricular contractions