transport systems - animals

• Blood contains plasma, red blood cells and white blood cells. It transports nutrients, oxygen and carbon dioxide.
• Red blood cells are specialised cells, so they efficiently transport oxygen.
• red blood cells are specialised:

  • Red blood cells contain no nucleus
  • Red blood cells are biconcave in shape
  • Red blood cells contain the protein haemoglobin
• Oxygen + Haemoglobin → Oxyhaemoglobin
• This is a reversible reaction and oxygen will dissociate from haemoglobin in body tissues, where there is a low concentration of oxygen.

  Oxygen + Haemoglobin ← Oxyhaemoglobin
• Pathogens are disease-causing micro-organisms (bacteria, viruses and fungi).
• The two types of white blood cells are:

  • Lymphocytes
  • Phagocytes
• Phagocytosis is the process by which phagocytes will engulf and digest the pathogen.
• phagocytosis process:

  • Phagocyte surrounds the pathogen
  • Phagocyte engulfs the pathogen and encloses it in a vacuole
  • Digestive enzymes within lysosomes in phagocytes digest the pathogen
• Lymphocytes produce antibodies which will bind to a specific protein on the pathogen, called an antigen.
• Antibodies will bind to several pathogens preventing the pathogen from spreading and allowing phagocytes to engulf the pathogen.
• Antibodies are specific and only one antibody is specific to one pathogen.
• heart structures

  
• Deoxygenated blood enters the right side of the heart through the vena cava and enters the right atrium. It is pumped into the right ventricle and is pumped out of the heart through the pulmonary artery to the lungs.
• Oxygenated blood returns from the lungs to the left side of the heart, it enters through the pulmonary vein into the left atrium. It is pumped out of the left atrium into the left ventricle and out of the left side of the heart to the rest of the body through the aorta.
• • Atria - pump blood into the ventricles
• Ventricles - pump blood out of the hear
• vena cava - brings deoxygenated blood from the body into the right atria
• • Pulmonary Vein - carries oxygenated blood to the left atria from the lungs
• • Pulmonary artery carries deoxygenated blood from the right ventricle to the lungs
• • Aorta carries oxygenated blood from the left ventricle to the rest of the body (except the lungs)
• valves - prevents the backflow of blood into the heart
• • Coronary arteries - provide the heart muscle with oxygen, glucose and amino acids
• Artery

  The Lumen of an artery is smaller than that of a vein and it has a thicker layer of smooth muscle to withstand the high pressure of blood. Arteries carry oxygenated blood from the heart to the body
• Veins have a larger lumen, a smaller layer of smooth muscle and carries deoxygenated blood (1 exception) under lower pressure. Veins also contain valve.
• Valves prevent backflow of blood.
• Capillaries have a large surface area and form a dense capillary network. They are only 1 cell thick to allow fast exchange of substances between the blood and body tissues.