Heart Structure 🫀

• arteries have.. 


  • narrow lumen
  • thick muscular walls
• capillaries have..

  • narrow lumen
  • very thin walls (to bring blood close to tissues)
• veins have..


  • large lumen
  • thin walls
  • valves
• explain the functions of the structure of a capillary


  • thick walls to prevent bursting
  • withstand high b.p
  • ensure blood ca travel long distances
• explain the functions of the structure of a capillary


  • narrow lumen so that only RBC can pass
  • thin walls to bring blood closer in contact with body tissues
  • supply cell with requirements
  • take away waste
• explain the functions of the structure of veins


  • wide lumen, less resistance to blood flow
  • no need strong walls as most b.p has been lost
  • valves prevent the back flow of blood
• what do arteries do?

  bring oxygenated blood away from the heart
• what do veins do?


  veins carry deoxygenated blood into the heart
• define double circulation


  • blood flows through the heart twice
  • for one complete circuit
  • back to the beginning
• which blood vessel has the thickest wall?


  left ventricle
• which blood vessel has the largest lumen?

  vena cava
• what is blood made up from?

  • RBC
  • WBC
  • plasma
  • platelets
• how do platelets clot blood?


  soluble fibrinogen -> insoluble fibrin
• blood clotting helps..

  • prevent excessive bleeding
  • pathogens from entering the body through breaks in the skin
• is fibrinogen a protein?


  yuh