Components and Functions of Blood

• What are the four main components of blood?

  Red blood cells, white blood cells, platelets and plasma
• What is the fluid called within the blood that carries the cells?

  Plasma
• What colour is plasma?


  Yellow
• Why is blood red?

  The presence of red blood cells
• Within plasma, dissolved substances like oxygen, glucose, urea and carbon dioxide will be transported around the body
• Blood transports gases, products of digestion, metabolic wastes and hormones around the body
• Blood controls the process of metabolism and keeps the body temperature at 37 degrees, in addition, it regulates the internal environment
• The blood protects the body against microbes and pathogenic organisms through immunity, along with the lymphatic system
• The platelets in the blood protects against bleeding through blood clotting
• What is the function of red blood cells?


  They carry oxygen from the lungs to respiring cells
• What are the adaptations of red blood cells?


  Biconcave shape, haemoglobin, no nucleus
• Why are red blood cells biconcave?


  It increases their surface area, which increases the diffusion of oxygen across the cell membrane into the haemoglobin (short diffusion pathway)
• Why do red blood cells contain haemoglobin?


  They bind to oxygen to allow oxygen transport
• Haemoglobin in red blood cells contains an atom of iron, which gives the pigment its red colour, this is the brightest when there is lots of oxygen bound to the haemoglobin
• Why do red blood cells have no nucleus?


  Allows more space for more haemoglobin to bind to oxygen
• Where are red blood cells produced?


  In the bone marrow of the backbone
• Where are red blood cells destroyed?


  In the liver, spleen and bone marrow
• The proteins in the haemoglobin are used in the formation of bile
• Why do people with sickle cell anaemia get fatigued and breathless quickly?


  They have misshapen red blood cells, which have a smaller volume, therefore they cannot hold as much haemoglobin, meaning that they cannot carry as much oxygen. The shape also causes oxygen diffusion to be slower as it has a smaller surface area
• White blood cells are colourless and uncleared cells that form part of the immune system
• Where are white blood cells produced?


  Bone marrow, spleen and the lymphatic system
• What is the function of white blood cells?


  To protect the body against infectious diseases
• What are the different types of white blood cells?


  Lymphocytes and phagocytes
• What is the function of lymphocytes?


  To produce antibodies or antitoxins
• What is the function of phagocytes?

  They continuously circulate in the blood, engulfing and digesting invading microorganisms
• Platelets are small fragments of cells without a nucleus, which are involved in the clotting of blood
• What is the process of clotting?


  A network of fibres are formed that traps more platelets and red blood cells to form a scab, which protects the new skin as it grows underneath and also prevents microorganisms from getting into the wound, thus preventing infection from occurring