6b. Transport in the blood

• Blood vessels are tubes that carry blood throughout the circulatory system.
• What is transported in the blood

  Red blood cells

  plasma

  white blood cells

  platelets
• What is transported in the plasma

  Carbon dioxide

  amino acids and glucose

  urea
• What is haemoglobin

  Protein that carries oxygen within red blood cells
• Describe structure of red blood cells

  biconcave discs

  no nucleus
• How is tissue fluid formed

  At the arterial end, blood pressure is greater than water potential gradient so water and solute are forced out, and this forms tissue fluid. there is a drop in blood pressure due to loss of friction. water potential in capillary decreases and there is an osmotic pull.
• Why is the water potential in capillary lower after tissue fluid formation

  Plasma proteins are too big to leave
• If something has a high affinity for oxygen what does it mean

  Readily/ easily binds
• Haemoglobin has a quaternary structure, why?

  Has 4 polypeptide chains
• What is co operative binding in haemoglobin

  When the first haem group binds with O, it changes the shape and uncovers the second haem group.
• What is the Bohr shift

  An increase in temp, acidity and co2 concentration causes the curve on the graph to move to the right.
• What is the significance of the Bohr shift

  Facilitates delivery of oxygen to the tissues for aerobic respiration
• If the curve moved to the left what does this do to affinity

  Increases it
• The the curve moves to the right what does this do to affinity

  Lowers it
• If haemoglobin has a low affinity what does it mean

  Unloads oxygen easily