Blood

• Components of blood


  • Plasma
  • Red blood cells
  • White blood cells
  • Platelets
• Plasma


  A yellow liquid that takes up about 40% of the blood, with dissolved carbon dioxide(waste of aerobic respiration), hormones and urea. Other nutrients such as protein or glucose are also dissolved in the plasma
• RBC = Erythrocytes
• Red blood cells


  • Make the blood red due to hemoglobin pigment
  • Carry oxygen
  • Smaller than other cells to go through tiny blood vessels
  • Bi-concave shaped for efficiency
  • Elastic and thin to expand/contract easily
  • No nucleus to have extra space for oxygen
  • No mitochondria to avoid using oxygen for itself, delivering it to other cells
  • One of the most abundant cells in the body
• WBC = Leukocytes
• White blood cells

  Have a special job to fight against diseases, which is called pathogens. It releases a substance called antibodies.
• Platelets = Thrombocytes
• Methods used by white blood cells to eliminate pathogens

  1. Release antibodies to kill pathogens directly

  2. Stick up pathogens together and capture/engulf them
• Platelets


  Clot wounds to create scabs
• Phagocytosis is a method of fighting against pathogen by releasing antibodies to stick them up and engulf them.