L10 - Heart

• What is the primary function of the cardiovascular system?

  To transport blood throughout the body
• What does the right side of the heart do?

  Receives oxygen-poor blood and pumps it to lungs
• What is the pulmonary circuit?

  Pathway for blood to and from the lungs
• What does the left side of the heart do?

  Receives oxygenated blood from lungs and pumps to body
• What is the pericardium?

  Double-walled sac covering the heart
• What is the function of the fibrous pericardium?

  Protects heart and prevents overfilling
• What is the serous pericardium?

  Double-walled connective tissue membrane
• What are the two layers of the serous pericardium?

  Parietal layer and visceral layer
• What is the pericardial cavity?

  Space between layers of serous pericardium
• What is the epicardium?

  Visceral layer of serous pericardium
• What is the myocardium?

  Main muscle layer of the heart
• How is the myocardium arranged?

  In bundles that swirl diagonally
• What is the endocardium?

  Epithelial tissue lining heart chambers
• What are the two atria in the heart?

  Thin-walled upper collecting chambers
• What veins enter the right atrium?

  Superior vena cava, inferior vena cava, coronary sinus
• How many pulmonary veins enter the left atrium?

  Four pulmonary veins
• What are the two ventricles in the heart?

  Thick-walled lower pumping chambers
• What does the right ventricle do?

  Pumps blood into pulmonary trunk
• What does the left ventricle do?

  Pumps blood into aorta
• What partitions separate the heart chambers?

  Interatrial septum and interventricular septum
• What are the two atrioventricular (AV) valves?

  Tricuspid valve and bicuspid valve
• How do AV valves function when the heart is relaxed?

  They hang loosely into the ventricles
• What happens to AV valves during ventricular contraction?

  Blood forces them closed against flaps
• What are chordae tendineae?

  Collagen strings anchoring AV valve flaps
• What is the function of semilunar valves?

  Prevent backflow of blood into ventricles
• What happens during ventricular contraction regarding semilunar valves?

  They are forced open to eject blood
• What is pulmonary circulation?

  Right side pumps blood to lungs
• What is systemic circulation?

  Left side pumps blood to the body
• What is coronary circulation?

  Supplies blood to the heart muscle
• What is a myocardial infarction?

  Blockage of blood flow to coronary vessels
• Why does cardiac muscle not regenerate?

  Temporary lack of oxygen causes fibrosis
• How do the right and left ventricles differ in workload?

  Right ventricle pumps low-pressure to lungs
• Why is the left ventricle thicker than the right?

  Generates higher pressure for systemic circulation
• What are the coverings of the heart?

  • Fibrous pericardium
  • Serous pericardium (parietal and visceral layers)
• Describe the structure and function of the three layers of the heart wall.

  • Epicardium: Visceral layer of serous pericardium
  • Myocardium: Main muscle layer, generates pumping action
  • Endocardium: Epithelial lining of heart chambers
• Describe the structure and functions of the four heart chambers.

  • Right atrium: Receives oxygen-poor blood
  • Left atrium: Receives oxygenated blood
  • Right ventricle: Pumps blood to lungs
  • Left ventricle: Pumps blood to body
• Explain the mechanism of operation of heart valves.

  • AV valves: Close during ventricular contraction
  • Semilunar valves: Open during ventricular contraction
• Trace the pathway of blood through the heart.

  1. Right atrium → Right ventricle → Pulmonary trunk
  2. Lungs → Left atrium → Left ventricle → Aorta
• True or False: The visceral pericardium covers the surface of the heart.

  True
• True or False: Pericardial fluid decreases friction between layers.

  True