Heart

• 3 components of the circulatory system

  Heart

  Blood vessels

  Blood
• Role of circulatory system m

  Transport substances around the body via the blood like nutrients, waste products and hormones or antibodies
• Double circulatory system

  Circulatory system has two loops

  Passes through the lungs and around the body
• Advantage of a double circulatory system

  Makes the circulatory system more efficient as blood can move around swiftly
• Role of heart

  Pump blood to lungs and body
• 4 chambers of the heart

  Right atrium

  Right ventricle

  Left atrium

  Left ventricle
• Which artery carries blood from the heart to the lungs?

  Pulmonary artery carries blood from the heart to the lungs
• Vein that carries blood away from the lungs to the heart

  Pulmonary vein
• Which side of the heart pumps deoxygenated blood to the lungs

  Right side
• Blood vessel that carries oxygenated blood into the left atrium

  Pulmonary vein
• Vena cava (right)

  Carries deoxygenated blood from the body into the right atrium
• Aorta (left)

  Carries oxygenated blood from the left ventricle to the body
• Why does the ventricles have thicker muscular walls than the atria?

  They have to pump the blood around the lungs or body whereas the atria only have to pump blood into the ventricles
• Why does the left ventricle have a thicker muscular wall?

  Has to pump blood around the entire body whereas the right ventricle only has to pump blood around the lungs.
• Purpose of valves in the heart

  Prevent the back-flow of blood
• Valves between the atria and ventricles

  Atrioventricular valves

  Right- tricuspid valve

  Left- bicuspid valve
• Valves between ventricles and arteries

  Semilunar valves
• Route that blood takes as it passes around the body

  Vena cava —> right atrium Left—> right ventricle —> pulmonary artery —> lungs —> pulmonary vein —> left atrium —> left ventricle —> aorta —> body —> vena cava
• Purpose of coronary arteries

  Supply the heart muscle with oxygenated blood
• Approximate value of resting heart rate

  70 bpm
• How is heart rate controlled

  Controlled by a group of cells in the right atrium which act as a pacemaker m. They release waves of electrical activity which cause the heart muscles to contract rhythmically
• Artificial pacemaker

  Device placed under the skin in the chest. Treats irregular heart rhythms by sending out regular waves of electrical activity like our pacemaker cells