6. Transport systems in animals

• Arteries are thick, elasticated walls to withstand high pressure.
• Veins contains valves to prevent the back flow of blood.
• Capillaries are thin, one cell-thick walls to allow gas exchange.
• The arteries carry blood away from the heart.
• The veins carries blood towards the heart.
• The capillaries have very low blood pressure.
• Blood is composed of four separate parts

  1. Red blood cells
  2. White blood cells
  3. Platelets
  4. Plasma
• Red blood cells are specialised to transport oxygen.
• Red blood cells contain large amounts of proteins called haemoglobin, which can bind to oxygen to produce oxyhaemoglobin.
• Red blood cells have a biconcave disc shape to maximise surface area.
• Red blood cells have no nucleus which allows more room for haemoglobin.
• Red blood cells are small and flexible to squeeze through capillaries.
• White blood cells are part of the immune system.
• White blood cells contains phagocytes that engulf, and digest, pathogens through phagocytosis.
• White blood cells also contain lymphocytes that produce antibodies which destroy pathogens.
• Pathogens are disease-casing microorganisms, bacteria, viruses etc.
• Platelets stop us bleeding out.
• Platelets circulate around the blood and clump together when they find damaged vessels.
• Plasma is the liquid component of blood.
• Plasma makes up over 50% of blood.
• Plasma transports carbon dioxide, nutrients and oxygen.
• The heart is a muscular pump that is responsible for pumping blood around the body.
• Deoxygenated blood is taken to the lungs to pick up oxygen.
• Oxygenated blood is transported around the body.
• The heart contains 4 chambers

  • Right atrium
  • Right ventricle
  • Left atrium
  • Left ventricle
• Atriums are the upper chambers of the heart.
• Ventricles are the lower chambers of the heart.
• The vena cava brings deoxygenated blood from the body to the heart.
• Pulmonary artery takes blood to the lungs.
• Pulmonary vein brings oxygenated blood from the lungs to the heart.
• Aorta pumps oxygenated blood around the body.
• Coronary artery provides the heart with its own blood supply.
• Labelled diagram of the blood vessels of the heart.

  
• Deoxygenated blood from the body is carried to the heart via the vena cava.
• The blood then flows into the right ventricle
• Once the right ventricle is full the blood is pumped through the pulmonary artery to the lungs.
• The blood is oxygenated at the lungs and is returned to the heart via the pulmonary vein.
• The blood enters through the left atrium then the blood fills the left ventricle.
• Once the left ventricle is full, the blood is pumped through the aorta to the body to deliver oxygen.
• The muscular wall of the left ventricle is thicker than the right. This is because the left ventricle has to pump blood all around the body rather than just around the lungs.