characteristics, types and functions of blood
- 1. Blood 1
- 2. . • Blood, vital fluid found in humans and other animals. provides important nourishment to all body parts carries away waste materials. • It is pumped from the heart through a network of blood vessels collectively known as the circulatory system. 2
- 3. Physical properties • Viscous fluid - Viscosity is the resistance of a fluid to flow due to cohesion between its particles • Temperature is 38ºC • pH range 7.35 – 7.45 (slightly alkaline) • NaCl concentration of 0.9% • Volume in male, 5 – 6 Lt, Female 4 – 5 Lt • 8% of the total body weight 3
- 4. Functions of Blood • Transportation – oxygen, carbon dioxide, waste, nutrients • Communication, i.e., hormones • Regulation pH Temperature - heating/cooling influences water content of cells • Protection blood loss via clotting mechanisms – hemostasis foreign microbes via white blood cells 4
- 5. Components of Blood • Formed elements Erythrocytes (red blood cells) Leukocytes (white blood cells) - Granular leukocytes neutrophils, eosinophils, basophils - Agranular leukocytes lymphocytes, monocytes Platelets (thrombocytes) • Extracellular fluid matrix: Plasma 5
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- 7. Red Blood Cells • Structure biconcave disc no nucleus or other organelles, such as Mitochondria no mitosis and minimal metabolic activity the only cell in the body that carries out anaerobic fermentation indefinitely has the red pigment called hemoglobin that carries oxygen cell surface has antigens responsible for the various blood types (ABO and Rh) Lifespan~120 days replacement rate~3x106 RBCs/sec 7
- 8. RBC Shape • Biconcave Disc, 7 μ (good measuring device) 1) Larger surface area 2) Strong and flexible 8
- 9. . inner membrane surface has the proteins, spectrin and actin, that gives the membrane resilience and durability that is need as they squeeze through capillaries. • Function hemoglobin combines with oxygen and carbon dioxide - globin – 4 proteins chains (two alpha and two beta chains) - heem- 4 nonprotein pigments and iron - oxygen attaches to iron 9
- 10. Structure of Hemoglobin (Hb) •Fe ion in heme group reversibly binds O2 •Hemoglobin picks up the O2 molecules and drops off CO2 10
- 11. RBC Production • Erythropoiesis – the process by which RBC’s are formed. starts in the RBM with a precursor cell called a proerythroblast proerythroblast divides several times, producing cells that begin to synthesize hemoglobin. 11
- 12. Stages of Erythropoiesis Pro-erythroblast: also called megaloblast erythropoiesis, w/r the production or synthesis of Hemoglobin begins Basophil erythroblast Early Normoblast the nucleoli inside the nucleus disappear, and the condensation of the chromatin network begins. Intermediate Normoblast: the chromatin network condenses further, and the haemoglobin begins to appear. 12
- 13. Late Normoblast The quantity of haemoglobin increases , and the nucleus begins to disintegrate and eventually disappears through a process called pyknosis. Reticulocyte the RBCs are still immature, but the cytoplasm is equipped with a reticular network Matured Erythrocyte finally evolves into a mature red blood cell with a biconcave shape. 13
- 14. 14 Fig. Stages of Erythroposis
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- 16. White Blood Cells (Leukocytes) • Have nuclei • Do not contain hemoglobin • Function as part of the bodies immune system • Grouped in to Granular leukocyte Agranular leukocyte • Granular leukocytes – have large granules in their cytoplasm and have bilobed nuclei. 16
- 17. . Three kinds: neutrophils –pale like-first responds to foreign invasion, phagocytic, release enzymes. eosinophils – stain red-orange with acidic dyes phagocyte, o release enzymes that combat the effects inflammation in allergic reactions and effective against parasitic infections. basophils – blue-purple- o release substances involved in inflammation and allergic reactions. Also called mast cells once in the tissue. 17
- 18. . • Agranular leukocytes – have no visible granules Two types: Lymphocytes o B cell – secretes antibody that is effective in destroying bacteria and deactivating toxins. oT cell – attack viruses, fungi, transplanted tissue and cancer cells Monocytes – differentiate into most important phagocytic cell, called macrophage when enter the tissue. 18
- 20. WBC Life Span Mostly live only a few days as compared to the 120 days of the red blood cells some B and T cells live for years • Leukocytosis – increase in the number of white cells. • Leukopenia – decrese in the number of white cells. 20
- 21. Platelets = Thrombocytes • Cell fragments of megakaryocytes of bone marrow (~ 4,000 thrombocytes per megakaryocyte) diameter ~ 160 µm • Lifespan ~ 12 days • Involved in blood clotting mechanisms Serves as a surface on which coagulation factors can act 21
- 22. . • Plasma consist of 91.5% water and 8.5% solutes (proteins, nutrients, gases, electrolytes, waste products, enzymes, and hormones) Transports organic and inorganic molecules, formed elements, and heat Plasma Proteins (90% from liver) plasma proteins – proteins found and confined only in the blood Albumin (60%)Major contributor to osmotic concentration of plasma. Transport of lipids and steroid hormones 22
- 23. • Globulins(35%) Transport ions, hormones, lipides; immune function • Fibrinogen(4%) Essential component of clotting system (conversion to insoluble fibrin) A type of blood protein called a globulin that interacts with thrombin to form fibrin • Regulatory proteins(< 1%) Protein-based hormones 23
- 24. Plasma Solutes • Lipoproteins= particles containing lipids (cholesterol & triglycerides) and proteins (albumins & globulins) • Electrolytes: Normal extracellular fluid ion composition • Organic nutrients: glucose, FA, AA • Organic wastes: urea, bilirubin • Dissolved gases • Nonprotein - based hormones –E.g., steroids 24
- 25. Formation of Blood • Hematopoiesis – the process by which blood cells are formed. In embryo there are multiple sites for blood formation. - Liver, spleen, thymus gland, lymph nodes and red bone marrow After birth blood production takes place in the red bone marrow of various long and flat bones. - Femur, humerus, sternum, ribs, vertebrae and cranial bone 25
- 26. . All blood cells originate from hemopoietic stem cells. - these cells differentiate into the five types of blood cells: erythrocytes granulocytes – eosinophils, neutrophils, basophils monocytes lymphocytes platelets agranulocytes 26
- 27. . • Hemocytoblast – multipotent stem cell capable of differentiating into multiple cells lines Red cells White cells Platelets 27
- 28. Hemopoiesis 28
- 30. Hemostasis – the stoppage of bleeding • Three mechanisms vascular spasm – when the smooth muscle in the vascular wall contracts which serves to reduce blood flow to the damaged vessel. platelet plug formation – platelet contact with damaged vessel causes a series of reactions that results in massive platelet adhesion at site of damage (platelet plug). reinforced with fibrins threads during coagulation. 30
- 31. . blood coagulation (clotting) – the process of clotting that involves a series of reactions that eventually lead to the production of fibrin threads that serve to reinforce the platelet plug and trap red blood cells. thrombosis – clotting in an unbroken vessel • Hemophilia – a sex linked hereditary absence of certain clotting factors that cause defective clotting. • Clot Retraction – the tightening of the fibrin clot that results in the pulling of the damaged blood vessels closer together. 31
- 32. . • Fibrinolysis – breaking up of the clot. plasminogen (inactive enzyme) is incorporated into the intial clot blood and body tissues release substances that convert plasminogen to plasmin (activated plasminogen) plasmin dissolves clot by digesting fibrin • Anticoagulants – substances that prevent clotting. heparin – anticoagulant produced by the mast cells, basophils and endothelial cells lining the blood vessels. 32
- 33. . • Thrombus – clotting in an undamaged vessel that can block circulation. • Vitamin K and Calcium are needed for formation. Vit. K is essential for the production of prothrombin and certain coagulation factors. it is normally produced by bacteria in the large intestine. 33
- 34. Rh system • Hemolytic disease of the new borne (Erythroblastosis) – occurs with an Rh‾ and a Rh+ fetus before or during delivery, Rh-positive erythrocytes from the fetus enter the blood of an Rh-negative women through a tear in the placenta. the mother is sensitized to the Rh antigen and produces Rh antibodies. Because this usually happens after delivery, there is no effect on the fetus in the first pregnancy. 34
- 35. AB0 blood grouping system 35
- 36. . 36
- 37. Rh factor 37
- 38. . • Many people also have a so called Rh factor on the red blood cell's surface. This is also an antigen and those who have it are called Rh+ . • Those who haven't are called Rh- . A person with Rh- blood does not have Rh antibodies naturally in the blood plasma (as one can have A or B antibodies, for instance). • But a person with Rh- blood can develop Rh antibodies in the blood plasma if he or she receives blood from a person with Rh+ blood, whose Rh antigens can trigger the production of Rh antibodies. • A person with Rh+ blood can receive blood from a person with Rh- blood without any problems. 38
- 39. Blood clumps or agglutinates? • For a blood transfusion, AB0 and Rh blood groups must be compatible between the donor blood and the patient blood. • If they are not, the red blood cells from the donated blood will clump or agglutinate. • The agglutinated red cells can clog blood vessels and stop the circulation. • The agglutinated red blood cells also crack and its contents leak out in the body. The red blood cells contain hemoglobin which becomes toxic when outside the cell. This can have fatal consequences for the patient. 39
- 40. . • The A antigen and the A antibodies can bind to each other in the same way that the B antigens can bind to the B antibodies. This is what would happen if, for instance, a B blood person receives blood from an A blood person. • The red blood cells will be linked together, like bunches of grapes, by the antibodies. As mentioned earlier, this clumping could lead to death. 40
- 41. Blood transfusions - who can receive blood from whom? • Of course you can always give A blood to persons with blood group A, B blood to a person with blood group B and so on. But in some cases you can receive or donate blood with another type of blood group. • The transfusion will work if a person who is going to receive blood has a blood group that doesn't have any antibodies against the donor blood's antigens. • But if a person who is going to receive blood has antibodies matching the donor blood's antigens, the red blood cells in the donated blood will clump. 41
- 42. . • People with blood group 0 Rh - are called "universal donors" and people with blood group AB Rh+ are called "universal receivers." • Rh+ blood can never be given to someone with Rh - blood, but the other way around works. E.g., 0 Rh+ blood can not be given to someone with the blood type AB Rh - . 42
- 43. Possible blood transfusion methods Recipients Donors O+ A+ B+ AB+ O- ** A- B- AB- O+ • • A+ • • • • B+ • • • • AB+ * • • • • • • • • O- • A- • • B- • • AB- • • • • 43