Blood.

• • Blood is composed of Plasma, Red blood cells, White blood cells, and platelets.​
• The plasma proteins are albumin, globulin, and fibrinogen.
• Arterioles are small arteries.
• All blood vessels have smooth muscles.
• Capillaries provide cells with nutrients and oxygen.
• Capillaries are where gas exchange occurs.
• Venules are small veins.
• Structure and function and adaptions of red blood cells are

  • Biconcave disc- increases surface area​
  • Diameter of 7.5-8μm- small enough to pass through the capillaries ​
  • No nucleus and few organelles- allows more haemoglobin to fit in ​
  • Haemoglobin: Has four subunits, each with an iron ion- allows transport of oxygen. ​
  • Contains enzyme carbonic anhydrase for the transport of carbon dioxide ​
• Production of red blood cells ​

  • Produced from cells in bone marrow​
  • Filled with haemoglobin which forces nucleus and other organelles out ​
  • In circulation for ~120 days​
  • Destroyed by special white blood cells in liver and spleen, before they wear out and break down in the blood ​
• • Platelets are involved in helping the blood clot​
  • Platelets are fragments of cells that are involved in blood clotting and forming scabs where the skin has been cut or punctured​
  • When the skin is broken (i.e. there is a wound) platelets arrive to stop the bleeding​
  • ...Platelets release chemicals that cause soluble fibrinogen proteins (a component of plasma) to convert into insoluble fibrin and form an insoluble mesh across the wound, trapping red blood cells and therefore forming a clot​
  • The clot eventually dries and develops into a scab to protect the wound from bacteria entering​
• White blood cells

  • Numbers fluctuate​
  • Formed from stem cells in the bone marrow​
  • Larger than red blood cells​
  • Do not contain haemoglobin and have a nucleus​
  • Lifespan: Varies from few days to years​
  • Function: Protection from infection ​
• White blood cells are large cells containing a big nucleus, different types have slightly different structures and functions.
• Arteries and arterioles ​

  • Carry blood away from the heart ​
  • Arteries split up into arterioles​
  • Have a thick muscular wall​
• Capillaries ​

  • Have a single celled wall​
  • Provide cells with nutrients and oxygen ​
• Venules and veins ​

  • Carry blood back to the heart ​
  • Venules merge into veins​
  • Veins contain valves to prevent backflow ​

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• Blood pressure- Force exerted by the blood on the blood vessels when it passes through them. Blood pressure can be measured by a sphygmomanometer.  
• Systolic Blood Pressure- Blood pressure when the ventricles are contracting​

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  Diastolic Blood Pressure- When the ventricle are relaxed and filling
• Blood plasma- makes up approximately 55% of the blood. Plasma contains 90% water and 10% dissolved molecules. Functions: carry everything else- transports materials needed by cells and materials that must be removed from the cells. carry hormones, urea, carbon dioxide, antibodies and digested nutrients.
• What is being measured within the blood which controls the rate of breathing?


  Carbon dioxide concentration.
• Blood vessels are composed of smooth muscles.
• Systolic Blood pressure measures... (eg. the first number in a blood pressure reading 120/80) The pressure in your arteries when your heart beats
• Diastoic Blood pressure measures... (eg. the second number in a blood pressure reading 120/80) The pressure in your arteriers when your heart rests.