heart

• what is the function of the arteries?

  carry blood away from the heart
• what do the arteries carry?

  oxygenated blood
• what kind of wall do arteries have?

  muscular
• what does having a narrow central cavity allow arteries to do?

  carry blood at high pressure
• what kind of walls do veins have?

  thin muscular wall
• why do veins have a wide central cavity?

  so they can carry blood at low pressure
• what is the function of the veins?

  carry blood back to the heart
• what does the veins carry?

  deoxygenated blood
• what do veins contain?

  valves to prevent backflow of blood
• what prevents the backflow of blood?

  valves
• what do capillaries have?

  large surface area
• what is special about capillaries cell walls?

  1 cell thick to allow for exchange of materials in tissues
• capillaries link arteries to veins
• where does blockages in blood occur?

  coronary artery
• what occurs in the coronary artery?

  blockage of blood
• Name the chemical messengers carried from one part of the human body to another in the blood

  hormones
• why are target tissues affected by chemical messengers?

  target tissues have receptors which are complementary to a hormone