Transport system

• Arteries


  Carry blood away from the heart
• Veins


  Carry blood towards the heart
• Capillaries


  Site of exchange of substances
• Xylem


  Transports water and mineral salts from the roots to the other parts of the plant
• Phloem


  Transports food from the leaves to other parts of the plant
• Xylem transports water and mineral salts
• Multi-cellular organisms need a transport system
• Diffusion


  The net movement of particles from a region of higher concentration to a region of lower concentration down a concentration gradient, till equilibrium is met
• Osmosis


  The net movement of water molecules from a region of higher water potential to a region of lower water potential through a partially permeable membrane
• Osmosis facilitates the absorption of water at the roots
• Drug abuse has detrimental effects on the transport system in humans
• There are ethical issues relating to organ transplants, such as donor consent and priority allocation
• Why do we need a transport system

  a transport system allows substances to be transported quickly in the organism.
• The transport system in humans


  a transport system allows substances to be transported

  
  

  1 Heart

  2. Blood

  3. Blood vessels
• Heart

  The heart is a muscular organ that pumps blood around the body

  
• Blood is made up of different

  substances

  Red blood cells – that carry oxygen

  • White blood cells – that help fight

  bacteria

  • Plasma – that carry dissolved

  substances such as digested food and

  waste products

  • Platelets – that help blood clot
• Comparison between the cross section of an artery, a vein and an artery

  Artery -Have thick muscular and elastic walls , small lumen , Semi-lunar valves absent

  
  

  Veins - Thin muscular walls with thin elastic tissue , have large lumen ,Semi-lunar valves are present

  
  

  Capillary-Walls are one-cell thick with no muscular or elastic tissues ,Have a large lumen,Semi-lunar valves absent

  
• Comparison between the cross section of an artery, a vein and a capillary

  Artery- blood is under high pressure , blood flows rapidly

  Vein- blood is under low pressure ,blood flows slowly

  Capillary- blood pressure is reduced and blood flows slowly

  
• 2 general function of blood

  Protective function-the white blood cell and platelets protect the body from infections and from losing too much blood.

  Transport function-the plasma and red blood cells transport useful such as oxygen, digested food and waste products such as carbon dioxide
• What is the advantage of the capillary being one cell wall thick?

  The capillary is involved in exchange of materials having the walls of the capillary one cell thick allows the exchange of substances to take place at a faster rate