Transport (humans)

• The red blood cells transport oxygen
• The platelets are the cells that help blood clot and form scabs.
• Plasma transports carbon dioxide , amino acids, hormones, heat
• White blood cells defend the body from pathogens
• Adaptations of the red blood cells are they contain haemoglobin, have a biconcave shape to maximise surface area for oxygen absorption, have no nucleus to contain more haemoglobin, small and flexible to fit through narrow blood vessels
• Haemoglobin is a red protein that combines with oxygen to form oxyhaemoglobin
• Each haemoglobin molecule can bind to 4 oxygen molecules
• the two types of white blood cells are lymphocytes and phagocytes
• Lymphocytes release antibodies specific to the pathogen
• Phagocytes ingest pathogens
• Phagocytes are attracted to the pathogens due to the chemicals it secretes, the pathogen binds to the receptors of the phagocyt. The pathogen produces a phagosome. Lysosomes release digestive enzymes into the phagosome digesting the pathogens
• Lymphocytes detect markets on the pathogens called antigens they’re able to release Y shaped proteins called antibodies . They have a complimentary shape to antigens which they stick to
• Memory cells remember particular antigens so if they appear in your body in the future your immune system can mount defense quicker
• Once the person is infected, lymphocytes produce antibodies after recognising foreign antigen, pathogen is killed, antibody concentration declines, memory cells remain, person exposed to the same pathogen for second time triggering immune response
• Plasma is 55%

  white blood cells and platelets are 5%

  red blood cells are 40%
• A person with anemia has less red blood cells than a normal persom
• Primary immune response happens when the immune system encounters an antigen for the first time
• Secondary immune response is when the immune system encounters the same antigen again usually after primary immune response has already taken place
• The heart is a muscular organ responsible for pumping blood around the body
• As the heart relaxes the valves close to prevent blood from back flowing. It makes sure the blood will flow in one direction
• Multicellular organisms need efficient transportation systems because simple diffusion would be too slow to transport nutrients and remove waste.