circulatory system

• what is blood made up of

  red blood cells, white blood cells, platelets and plasma
• red blood cells 


  carry oxygen around the body

  the bi concave increase the surface area
• white blood cells 


  defends body against pathogens

  they have a nucleis and are larger than red blood cells but don’t contain pigment
• plasma 


  carries dissolved substances

  this liquid is 90percent water and it distributes heat around the body
• how does blood travel

  blood travels round the body via a network of vessels
• arteries 


  carry blood away from the heart under high pressure

  walls are thick to withstand pressure

  limen is small to maintain pressure
• capillaries 


  walls are thin

  only one blood cell at a time can get through

  it’s one cell thick
• veins 


  to the heart

  thicker walled blood cells

  lumen is wide

  valve prevents backflow
• coronary artery


  supplies oxygen
• coronary vein


  removes carbon dioxide from the heart
• What process allows oxygen to move from the alveoli into the red blood cells?

  Diffusion
• What happens to oxygenated blood after it re-enters the heart via the pulmonary vein?

  It fills the left atrium
• What occurs when the left atrium contracts?

  Oxygenated blood fills the left ventricle
• What is the result of the left ventricle contracting?

  Blood is forced into the aorta
• How does blood travel away from the heart?

  Through arteries
• How is oxygenated blood delivered to the tissues?

  It is carried by capillaries
• What happens to oxygen as blood moves around the body?

  Oxygen diffuses out of blood and into cells
• How does deoxygenated blood return to the heart?

  Through veins
• From where does deoxygenated blood fill the right atrium?

  From the vena cava
• What occurs when the right atrium contracts?

  Blood fills the right ventricle
• What happens when the right ventricle contracts?

  Blood is forced into the pulmonary artery
• why are the walls of the atria thinner than the walls of the ventricles

  ventricle has to pump blood around the body the atrium only pumps it to the ventricle
• why is the wall on the left ventricle thicker than the wall on the right ventricle

  because it has to pump blood around the body while the right only pumps it to the lungs
• what is the role of the septum in the heart

  divides the 2 sides of the heart preventing oxygenated blood from mixing with deoxygenated blood
• descirbe the difference between the composition of the blood in the left side and right side of the heart

  left side has oxygenated blood with no carbon dioxide right side has deoxygenated blood with a high concentration of oxygen
• semi lunar 


  ventricle, aorta and pulmonary artery
• triscuspid valve 


  right atrium, right ventricle
• biscuspid valve 


  left atrium and left ventricle
• What does the pulmonary artery carry?

  Deoxygenated blood from the lungs to the heart
• What is the function of the vena cava?

  It carries blood from the body back to the heart
• What are the semi-lunar valves' function in the heart?

  • Prevent backflow of blood from the arteries to the heart
  • Operate when ventricles relax
• What does the aorta do?

  It carries blood to the body
• What does the pulmonary vein carry?

  Oxygenated blood from the lungs to the heart
• What is the role of the left atrium?

  It receives oxygenated blood from the pulmonary veins
• What is the role of the right atrium?

  It receives deoxygenated blood from the vena cava
• What is the function of the right atrio-ventricular valve (tricuspid)?

  • Prevents backflow of blood to the right atrium
  • Operates when the right ventricle contracts
• What does the right ventricle do?

  It pumps deoxygenated blood to the lungs
• What is the function of the left atrio-ventricular valve (bicuspid)?

  • Prevents backflow of blood to the left atrium
  • Operates when the left ventricle contracts
• What does the left ventricle do?

  It pumps oxygenated blood to the body
• What does CVD stand for in the context of human health?

  Cardiovascular disease