Download
carriage of respiratory gases n.
Skip this Video
Loading SlideShow in 5 Seconds..
Carriage of respiratory Gases PowerPoint Presentation
Download Presentation
Carriage of respiratory Gases

Carriage of respiratory Gases

92 Vues Download Presentation
Télécharger la présentation

Carriage of respiratory Gases

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. Carriage of respiratory Gases By Y Stock

  2. Objectives • You should be able to: • Describe the structure of erythrocytes. • Describe the role of respiratory pigments. • Understand and interpret dissociation curves.

  3. WWW.NIM.NIH.GOV

  4. Red blood cells • Biconcave discs • 8 micrometers diameter • No nucleus • Made in bone marrow • Destroyed by liver/spleen

  5. Function: To carry oxygen and carbon dioxide • Adaptions: • Shape gives a large surface area, encouraging diffusion • Full of haemoglobin

  6. www.astrographics.com/.../Display/GP2120.jpg

  7. Haemoglobin www.chemsoc.org/.../LearnNet/cfb/images/13A.jpg

  8. Haemoglobin • Consists of 4 polypeptide chains, each with an iron containing haem group. • Each haem group combines with an oxygen molecule

  9. Haemoglobin+oxygen=oxyhaemoglobin • Hb + 4O2 = HbO8 • Reversible reaction

  10. www.scientific-art.com/.../Haemoglobin.gif

  11. High partial pressure oxygen Lungs Oxyhaemoglobin formed Low partial pressure oxygen Active tissues Oxyhaemoglobin breaks down Oxygen released Hb + 4O2 = HbO8

  12. Oxygen dissociation curves • Found by exposing haemoglobin to air mixtures of varying oxygen partial pressures and determining its % saturation.

  13. www.jcu.edu/biology/RESPS.JPG

  14. S shaped curve • Over the steep section a small fall in Oxygen partial pressure causes a sizeable drop in % saturation.

  15. The curve shows that: • at relatively low oxygen concentrations there is uncombined haemoglobin in the blood and little or no oxyhaemoglobin, e.g. in body tissue • at relatively high oxygen concentrations there is little or no uncombined haemoglobin in the blood; it is in the form of oxyhaemoglobin, e.g. in the lungs.

  16. Effect of increased carbon dioxide

  17. Bohr Effect • Curve shifted to right • Increased CO2causes oxyhaemoglobin to unload some of its oxygen.

  18. www.coheadquarters.com/Bohr1.gif

  19. Fate of carbon dioxide • 7-10% dissolves in plasma • 20-30% in red cells as carbaminohaemoglobin (binds to amino acids) • 60-70% converted to bicarbonate in plasma

  20. Conversion to bicarbonate • Carbon dioxide diffuses into red cells • Enzyme:carbonic anhydrase • CO2 + H2O = H2CO3

  21. This dissociates • H2CO3 = H+ + HCO3- • HCO3- diffuses into plasma • H+ combine with oxyhaemoglobin forming haemoglobinic acid. • H+ + HbO2 = HHB + O2 • Oxygen displaced. • Haemoglobin buffering pH changes

  22. www.colprado.edu/.../image/figure13g.jpg

  23. Myoglobin -Curve shifted to left • Myoglobin binds more tightly to oxygen. • Oxygen only given up at very low PO2

  24. Images.encarta,msn.com/…/cha/00076b5f.gif

  25. Quiz Haemoglobin quiz image search RSC