blood - circulatory system

• What is blood classified as?

  Blood is classified as a tissue.
• What is one of the main jobs of blood?

  One of its jobs is to act as a huge transport system.
• What are the four main components found in blood?

  • Red blood cells
  • White blood cells
  • Platelets
  • Plasma
• What is the primary function of red blood cells?

  The job of red blood cells is to carry oxygen from the lungs to all the cells in the body.
• What shape do red blood cells have and why?

  They have a biconcave disc shape to provide a large surface area for absorbing oxygen.
• Why do red blood cells not have a nucleus?

  They don't have a nucleus to allow more room to carry oxygen.
• What pigment do red blood cells contain?

  They contain a red pigment called haemoglobin.
• What happens to haemoglobin in the lungs?

  In the lungs, haemoglobin binds to oxygen to become oxyhaemoglobin.
• What occurs to oxyhaemoglobin in body tissues?

  Oxyhaemoglobin splits up into haemoglobin and oxygen to release oxygen to the cells.
• What is the role of white blood cells?

  White blood cells defend against infection.
• How do some white blood cells respond to microorganisms?

  Some can change shape to gobble up unwelcome microorganisms in a process called phagocytosis.
• What do other white blood cells produce to combat microorganisms?

  Others produce antibodies to fight microorganisms and antitoxins to neutralize any toxins produced by the microorganisms.
• Do white blood cells have a nucleus?

  Yes, unlike red blood cells, they do have a nucleus.
• What are platelets?

  Platelets are small fragments of cells that have no nucleus.
• What is the function of platelets in the blood?

  They help the blood to clot at a wound to stop blood loss and prevent microorganisms from entering.
• What can a lack of platelets cause?

  A lack of platelets can cause excessive bleeding and bruising.
• What is plasma and what does it carry?

  • Plasma is a pale straw-coloured liquid.
  • It carries:
  • Red and white blood cells and platelets
  • Nutrients like glucose and amino acids
  • Carbon dioxide from the organs to the lungs
  • Urea from the liver to the kidneys
  • Hormones
  • Proteins
  • Antibodies and antitoxins produced by white blood cells