Components of blood

• What are the three main components of the cardiovascular system?


  Blood, blood vessels, and the heart
• What are the components of blood?

  • Cells
  • Plasma
• What does plasma transport in the blood?


  Blood cells, CO2, urea, products of digestion, hormones, and clotting factors
• What are platelets and their function?


  Cell fragments involved in blood clotting and repair of minor breaks in blood vessels
• How many red blood cells are there in each mm³ of blood?


  5 million
• Why is the small size of red blood cells important?


  It allows haemoglobin to be close to the cell surface for diffusion and easier flow through capillaries
• What is the significance of the biconcave shape of red blood cells?


  It provides a high surface area to volume ratio
• Why do red blood cells lack a nucleus and organelles?


  To provide more room for haemoglobin
• How does haemoglobin function in red blood cells?


  It carries oxygen and affects the water potential of blood
• How many molecules of haemoglobin does each red blood cell contain?


  Nearly 300 million
• What are polymorphs also known as?


  Microphages
• What is the function of polymorphs in the blood?


  They are phagocytic and destroy bacteria and foreign bodies
• What percentage of white blood cells are polymorphs?


  70%
• What is the characteristic of monocytes?


  They have a bean-shaped nucleus and are the largest but least common white blood cells
• What do monocytes develop into at sites of infection?


  Phagocytic macrophage cells
• How do monocytes compare to polymorphs in terms of lifespan?


  Monocytes live longer than polymorphs
• What percentage of white blood cells are lymphocytes?


  20-25%
• What is the structure of lymphocytes?


  They have a very large nucleus with only a small amount of cytoplasm
• What are the two types of lymphocytes and their functions?

  • B-cells: Antibody production
  • T-cells: Mediating immunity and destroying infected or foreign cells