Cardiovascular system

• Cardiovascular system

  • Has two main functions:
  • Transport of substances (e.g. oxygen, carbon dioxide, nutrients)
  • Temperature control (by moving more blood near the skin to cool the body)
• How the heart pumps blood around the body

  1. Pulmonary circuit: Deoxygenated blood enters right ventricle, pumped to lungs, oxygenated blood enters left atrium

  2. Systemic circuit: Oxygenated blood enters left ventricle, pumped to body, deoxygenated blood enters right atrium
• The cardiovascular system is a double-circulatory system with two circuits: pulmonary and systemic
• Pressure in the heart causes the valves to open and close to control the direction of blood flow
• Cardiovascular system

  System that has different types of blood vessels that carry blood around the body
• Types of blood vessels

  • Arteries
  • Veins
  • Capillaries
• Blood vessels

  • Have a hollow centre called the lumen so blood can flow through
• Arteries

  • Carry blood away from the heart
  • Have thick, muscular walls to carry blood at high pressure
• Capillaries

  • Have a large lumen
  • Have thin walls
  • Have thin muscle
• Veins

  • Carry blood towards the heart
  • Have valves to stop blood flowing the wrong way
  • Have thinner walls and less muscle than arteries
• Capillaries

  • Carry blood through the body to exchange gases and nutrients
  • Have very thin walls so substances can easily pass through
  • Are very narrow, allowing many to fit in the body's tissues and giving a large surface area for gas exchange
  • Cause blood to flow slowly, giving more time for gas exchange
• Heart rate


  Number of times the heart beats per minute
• Stroke volume

  Amount of blood each ventricle pumps with each contraction
• Cardiac output

  Volume of blood pumped by a ventricle per minute
• Red blood cells

  • Carry oxygen and transport it around the body to be used to release energy needed by muscles during physical activity
  • Carry carbon dioxide to the lungs
  • Haemoglobin (a protein in red blood cells) stores oxygen and carbon dioxide
• Arteries carry blood away from the heart, veins carry blood towards the heart
• diagram of heart


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