Blood

• Name the 4 components of blood.

  Red blood cells, white blood cells, platelets, plasma.
• What is blood plasma?

  A yellow liquid within blood that transports substances around the body.
• Which substances are dissolved in blood plasma?

  1. Nutrients - glucose, amino acids, fatty acid, glycerol.
  2. Waste products - carbon dioxide, urea.
  3. Other - hormones, antibodies.

  Plasma also transports red blood cells, white blood cells, and platelets, but these are not dissolved in the plasma.
• What is the role of red blood cells in blood?

  Oxygen transport.
• How are red blood cells adapted to their function?

  1. Contain haemoglobin - which binds to oxygen.
  2. Biconcave shape - which increases the surface area to volume ratio.
  3. No nucleus - can fit more haemoglobin in the cell.
• What is the role of white blood cells in blood?

  They form part of the immune system.
• How are white blood cells adapted to their function?

  1. Some can produce antibodies.
  2. Some can produce antitoxins.
  3. Some can engulf and digest pathogens.
• What is the role of platelets in the blood?

  Platelets play a crucial role in blood clotting and help to prevent excessive bleeding.
• Give two reasons why blood clotting is important.

  1. It prevents blood from leaving the bloodstream.
  2. It prevents microorganisms from entering the bloodstream (which could cause infection).