Transport in animals

• Open circulatory system 


  Very few vessels to contain blood and is pumped straight from heart to body cavity
• closed circulatory system 


  the blood is enclosed in vessels and doesn’t come in direct contact with body cells
• single closed circulatory system

  the blood travels only once through the heart for each complete circulation of the body
• double closed circulatory system

  the blood travels twice through the heart for each complete circuit of the body

  1. blood is pumped from heart to lungs to pick up oxygen and unload carbon dioxide
  2. blood then flows back through heart and is pumped out to travel all around the body before returning back to the heart
• artery components

  1. carries blood away from the heart
  2. walls contain elastic fibre - withstands force of blood being pumped out heart
  3. smooth muscle - blood flows easily over it
  4. collagen
• capillaries components (diffusion of substances)

  1. link arterioles with venules
  2. small lumen -substances are exchanged through the walls between tissue cells and blood
  3. large surface area - for diffusion of substances in and out of blood
  4. 1 cell thick -thin layer for diffusion
• veins and venules components

  1. carries deoxygenated blood towards the heart (pulmonary vein carries oxygenated blood from lungs to heart)
  2. low pressure - contain valves to prevent back flow of blood
  3. lots of collagen and wide lumen - for easy blood flow
• components of blood

  1. Plasma - carries variety of components such as mineral ions , amino acids and hormones
  2. white blood cells - fight infection
  3. red blood cells - carry oxygen
  4. platelets - cause blood to clot
• oncotic pressure 


  Tendency of water to move into the blood by osmosis
• the Bohr shift 


  As the partial pressure of carbon dioxide increases, haemoglobin gives up oxygen more easily therefore shifting it to the right on the graph