The heart

• What is the primary function of the heart?

  To pump blood around the body
• What are the four chambers of the heart?

  • Left atrium
  • Right atrium
  • Left ventricle
  • Right ventricle
• Where are the left and right atria located in the heart?

  At the top of the heart
• Where are the left and right ventricles located in the heart?

  At the bottom of the heart
• Why are the ventricles thicker than the atria?

  They pump blood around the entire body
• What allows the left ventricle to contract powerfully?

  Its thick wall of muscle
• What is the function of the heart valves?

  To prevent the backflow of blood
• What do the atrioventricular (AV) valves connect?

  Atria to the ventricles
• What do the semi-lunar (SL) valves connect?

  Ventricles to the pulmonary artery and aorta
• How does deoxygenated blood return to the heart?

  Through the Vena Cava into the right atrium
• What happens when the right atrium fills with blood?

  The wall contracts, forcing the tricuspid valve open
• How does blood move from the right ventricle to the lungs?

  Through the pulmonary artery after contraction
• What returns oxygenated blood to the heart?

  Via the pulmonary vein
• What occurs when the left atrium fills with blood?

  It contracts, forcing the bicuspid valve open
• What happens when the left ventricle is full?

  It contracts and forces blood upwards
• What closes the bicuspid valve?

  Increase in blood pressure in the ventricle
• What happens to blood after it is forced into the aorta?

  It is sent to the body at high pressures
• How do heart valves function?

  • Open in one direction
  • Open based on pressure differences
  • Prevent backflow of blood
• What ensures blood flows unidirectionally in the heart?

  Valves that open based on pressure
• What divides the heart into right and left sides?

  The internal septum
• What does the right side of the heart do?

  Pumps blood to the lungs
• What does the left side of the heart do?

  Pumps blood to the body
• What type of muscle makes up the heart walls?

  Cardiac muscle
• What happens when the ventricles contract?

  The atria are relaxed
• What prevents backflow between the ventricles and atria?

  Atrioventricular valves
• What are the names of the atrioventricular valves?

  Tricuspid and bicuspid valves

  
• How does blood enter the heart?

  From the vena cava and pulmonary veins
• What happens to the atrioventricular valves during atrial contraction?

  They are forced open
• What prevents the atrioventricular valves from turning inside out?

  Chordae tendineae (heart strings)
• What are the semi-lunar valves at the base of the arteries?

  Aortic valve and pulmonary valve
• What is the flow sequence of blood through the heart?

  Vein -> Atrium -> Ventricle -> Artery
• Why does blood flow from atria to ventricles?

  Due to pressure generated by heart contraction
• What happens when the atria contract?

  Pressure in the atria is higher than in ventricles
• What occurs when the ventricles contract?

  Pressure exceeds that of the atria
• What prevents backflow into the ventricles?

  Closure of the semi-lunar valves
• What happens when the ventricles relax?

  Pressure falls below that in the arteries
• What is the movement of blood based on?

  From high to low pressure
• What happens as blood enters an artery?

  Pressure increases in the vessel
• How is backflow prevented in arteries?

  By closure of the semi-lunar valves
• What type of organ is the heart?

  Four-chambered organ