- Red blood cells (erythrocytes) transport oxygen from the lungs to tissues and carbon dioxide from tissues back to the lungs. They develop from stem cells in the bone marrow in a multi-step process called erythropoiesis. - Mature red blood cells are biconcave disks that are flexible and can change shape, allowing them to flow through narrow blood vessels. They contain the protein hemoglobin which binds oxygen and gives blood its red color. - Red blood cells have an average lifespan of 120 days, after which they are broken down and recycled. Around 2.5 million new red blood cells are produced every second to replace those that die off.

1. introduction BLOOD Dr Alamzeb MBBS M.Phil Assistant Professor

3. Dr Alamzeb MBBS M.Phil Assistant Professor

5. Review Levels of Organization

11. Energy Flow and Law of Mass Balance All living processes require constant input of energy Where from? - How is it stored? How is it used to do work? Total amount of substance in body = intake + production - output What substances are maintained through law of mass balance? Major routes for output? Major routes for input?

14. A speck of blood (1 cu mm)

16. Dr Alamzeb MBBS M.Phil Blood is the most commonly tested part of the body, Screening, Diagnosis & prognosis of diseases

17. Easily accessible

18. Easily obtainable Dr Alamzeb MBBS M.Phil

19. Easily testable Dr Alamzeb MBBS M.Phil

22. If we take some blood, prevented from clotting, in a centrifuge, after centrifugation we have this result.

23. Let us understand the composition of the sedimented blood:

24. Composition of Blood Blood consist of 1 Red cell 2 White cell 3 Platelets 4 Plasma – in which the above elements are suspended Plasma is the liquid component. which contain soluble fibrinogen Serum is what remains after the formation fibrin clot Dr Alamzeb MBBS M.Phil

26. BLOOD. Blood is also vital to maintain a stable body temperature by varying the amount of blood to different areas of the body. To do all this, the heart pumps about 2,000 gallons (9100 liters) of blood per day; its valves operate some 5000 times per hour , and it never stops for maintenance...not even once! The Bible said a long time ago that " the life of the flesh is in the blood ." Dr Alamzeb MBBS M.Phil

27. RBCs Dr Alamzeb MBBS M.Phil

29. Dr Alamzeb MBBS M.Phil

30. RED BLOOD CELLS Dr Alamzeb MBBS M.Phil

34. RED BLOOD CELLS Dr Alamzeb MBBS M.Phil

39. Size at thin point 1 micron at thinnest point The average volume of the red blood cell is 90 to 95 cubic micrometers. Dr Alamzeb Dr Alamzeb MBBS M.Phil

41. Thickness continue A sheet of paper is approximately 75 micron thick Therefore 10 Erythrocytes could be aligned side by side across the edge of a sheet paper Dr Alamzeb MBBS M.Phil

42. Shape of RBCs Under Microscope Red blood cells (erythrocytes) shown above in a stained slide. Note how they stain darker at the edges than in the middle reflecting their biconcave shape. Dr Alamzeb MBBS M Phil

43. Appearance under microscope Red blood cells (erythrocytes) shown in a stained slide. Note how they stain darker at the edges than in the middle reflecting their biconcave shape.

50. Change of shape As you can see by the above photomicrograph red blood cells in life are highly deformable and are able to squeeze through minute gaps.

51. Dr Alamzeb MBBS M.Phil

54. production Dr Alamzeb MBBS M.Phil break down Functions Of RBCs

77. Hypoxia Erythropoietin RBCs production factors that decrease tissue oxygenation 1 Low blood volume 2 anemia 3 low hemoglobin 4 poor blood flow 5 pulmonary disease 6 cardiac disease 8 hemorrhage Decrease Tssue oxygenation Increase Erythropoietin kidney Hemopoietic stem cells Proerythroblasts Red blood cells Dr Alamzeb MBB M.Phil

80. Hemoglobine break down Dr Alamzeb MBBS M.Phil

81. S U M M E R Y Alamzeb MBBS M.Phil

82. Functions of RBCs Dr Alamzeb MBBS M.Phil

86. Chemical reaction CO2 + H2O H2CO3 H + + HCO 3- Carbonic Anhydrase carbon dioxide + water carbonic acid + hydrogen ion + bicarbonate ion Alamzeb MBBS M.Phil