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Review exam questions

Review exam questions. starter. http://www.youtube.com/watch?v=Qrvrs6RXxwY. Starter - Key Word Revision. Erythrocyte (RBC) Dissociation Partial pressure Oxyhaemoglobin (Hb + 4O2  HbO8 ) Biconcave Oxygen Dissociation Curve Diffusion Plasma Saturated Platelets. Bone Marrow Blood

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Review exam questions

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  1. Review exam questions

  2. starter http://www.youtube.com/watch?v=Qrvrs6RXxwY

  3. Starter - Key Word Revision • Erythrocyte (RBC) • Dissociation • Partial pressure • Oxyhaemoglobin (Hb + 4O2  HbO8) • Biconcave • Oxygen Dissociation Curve • Diffusion • Plasma • Saturated • Platelets

  4. Bone Marrow • Blood • Oxygen • Association • Carbon Dioxide • Bohr Effect • Leukocyte (WBC) • Alveoli • Haemoglobin

  5. Transport of carbon dioxide H+

  6. OBJECTIVES • Describe the 3 ways in which carbon dioxide is carried in the blood • Describe the importance of the formation of hydrogen carbonate in the carrying of carbon dioxide in the blood. • Describe and explain the Chloride shift.

  7. KEY TERMS • Haemoglobin • Carbamino-haemoglobin • Carbonic Acid • Carbonic anhydrase • Haemoglobinic acid (HHb) • Buffer • Chloride Shift

  8. Carbon Dioxide Transport • Carbon dioxide is transported through the circulatory system in 3 ways: • Dissolved in plasma (5%) • Associated with Hb to form carbaminohaemoglobin (10%) • (Changes shape of haemoglobin and encourages oxygen dissociation)

  9. CO2 Transport – 3rd Way Sequence of events in which hydrogen carbonate is formed is significant for a number of reasons • 85% of CO2 is transported as hydrogen carbonate ions • CO2 dissolves in water to form carbonic acid (via carbonic anhydrase catalyst in RBC) CO2 + H2O  H2CO3 • Carbonic acid releases H+ protons (acid dissociation – chemistry) • H2CO3  HCO3- + H+

  10. CO2 Transport – 3rd Way • Question 1: • What will happen to the nvironment • within the erythrocyte? • H+ ions bind to Hb to form haemoglobinic acid • Question 2: • If Hb is absorbing H+ ions, what can • we say Hb is acting as?

  11. CO2 Transport – 3rd Way Sequence of events in which hydrogen carbonate is formed is significant for a number of reasons • 85% of CO2 is transported as hydrogen • carbonate ions • H+ ions lower blood pH and combine with Hb to make haemoglobinic acid (HHb) decreasing Hb O2 affinity (Bohr) • H+ + HB  HHb • HCO3- ions diffuse out of erythrocyte. • Cl- diffuse into the cell to balance the charge  CHLORIDE SHIFT

  12. CO2 effect on O2 Dissociation • Conclusion: • In a CO2-rich environment (i.e. at respiring tissue), more oxygen dissociates from oxyhaemoglobin • Oxygen dissociation curve shifts to the right • (requires higher pO2 to saturate Hb due to H+ competition) • This is known as the Bohr effect

  13. CO2 Transport – 3rd Way Sequence of events in which hydrogen carbonate is formed is significant for a number of reasons • 85% of CO2 is transported as hydrogen • carbonate ions • CO2 dissolves in water to form carbonic acid (via carbonic anhydrase catalyst in RBC) CO2 + H2O H2CO3 • Carbonic acid releases H+ protons (acid dissociation – chemistry) • H2CO3  HCO3- + H+ • H+ lower blood pH and combine with Hb to make haemoglobinic acid decreasing Hb O2 affinity (Bohr) • H+ + HB  HHb • HCO3- ions diffuse out of the erythrocyte. • Cl- diffuse into the cell to balance the charge  CHLORIDE SHIFT

  14. TASK: Write equations for the following steps • CO2 dissolves in water to form carbonic acid (via carbonic anhydrase catalyst in RBC) • Carbonic acid releases H+ protons (acid dissociation – chemistry) • H+ lower blood pH and combine with Hb to make haemoglobinic acid decreasing Hb O2 affinity (Bohr) • HCO3- ions diffuse out of the erythrocyte & Cl- diffuse into the cell to balance the charge  CHLORIDE SHIFT EXT – Link these equations into a sequence (in a red blood cell so you can show what is & isn't inside the cell)

  15. CO2 CO2 + H2OH2CO3H+ + HCO3- Carbonic anhydrase Conformational change Decreased affintiy for O2

  16. CO2 effect on O2 Dissociation • We know that oxygen dissociates from • oxyhaemoglobin where the pO2 is low • (i.e. in respiring tissue). • If H+ ions can bind with Hb, they must compete with oxygen • In respiring tissue: • More CO2 produced • More Carbonic acid formed • More H+ dissociated • More competition for Hb • More oxygen dissociation

  17. Formation of hydrogen carbonate • Build up of hydrogen carbonate ions causes them to diffuse out of RBC leaving inside of RBC positively charged. • To balance electric charge Cl- ions diffuse into the RBC from plasma – this is known as the chloride shift. In this reaction Hb is acting as a buffer

  18. http://www.youtube.com/watch?feature=player_embedded&v=x26TWL3VKMghttp://www.youtube.com/watch?feature=player_embedded&v=x26TWL3VKMg http://www.youtube.com/watch?feature=player_embedded&v=bklrcFuiH-8

  19. Breakdown of hydrogen carbonate • When blood gets to the lungs, all the reactions are reversed • The hydrogen carbonate and hydrogen ions recombine releasing CO2 • The chloride shift is reversed • Carbamino-haemoglobin breaks down to release CO2 CO2 + H2OH2CO3H+ + HCO3- H+ + HCO3-  H2CO3  CO2 + H2O

  20. enzyme Transport of carbon dioxide • In tissue : plasma + CO2 + H2O H+ HCO3-

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