blood vessels and composition

• what are the 3 types of blood vessels?

  arteries - carry blood away from the heart

  veins - carry blood towards the heart

  capillaries - involved in the exchange of gas materials with tissues
• what are key features of arteries?

  carry oxygenated blood at high pressure away from the heart.

  have a narrow lumen

  have thick muscular walls that contain elastic fibres

  blood flows at a high speed
• how is the artery adapted for its function?

  thick muscular walls --> withstand the high pressure

  elastic fibres in walls --> maintain blood pressure as they can spring back/stretch/recoil after blood passes

  narrow lumen --> helps maintain high pressure
• what type of blood do arteries carry?

  oxygenated
• what is the only artery that doesnt carry oxygenated blood?

  pulmonary
• what type of blood pressure and speed do arteries carry?

  high
• what kind of lumen do arteries have?

  narrow
• what do arteries walls contain to help them stretch and maintain blood pressure?

  elastic fibres
• what are the key features of veins?

  carry deoxygenated blood at low pressure towards the heart

  have thin walls

  carry blood at low pressure and slow speeds

  have larger lumen than arteries

  contain valves
• how are veins adapted to their function?

  large lumen --> reduces resistance to blood flow under low pressure

  valves --> prevent backflow of blood as it is under low pressure
• what type of pressure and speed to veins carry blood at?

  low
• what is the only vein that carries oxygenated blood to the heart?

  pulmonary
• what do veins contain to prevent backflow?

  Valves
• veins take blood back to the heart
• key features of capillaries?

  small

  carry blood at low pressure within tissues

  have permeable walls that are one cell thick

  supply oxygenated blood and nutrients to tissue

  take away waste and deoxygenated blood

  slow blood flow
• how is the structure of a capillary adapted?

  walls are one cell thick --> short diffusion distance means substances can easily diffuse in and out of them
• what does blood contain?

  
red blood cells, plasma, white blood cells and platelets
• platelets are used to clot the blood after a wound, to prevent excessive bleeding by reducing blood flow around the wound
• how are red blood cells adapted to carry oxygen to the body?

  small + flexible = pass through capillaries

  biconcave disk = maximises diffusion of oxygen

  no nucleus = more space for haemoglobin
• what is plasma?

  a liquid which the other components of the blood are suspended within
• what does plasma transport?

  RBC's, WBC'S and platelets.

  water, carbon dioxide

  digested food and mineral ions

  urea

  hormones

  antibodies

  heat energy