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Blood

Blood. Components. Blood is the only fluid tissue in the body Blood consists of living blood cells, called formed elements, suspended in a nonliving fluid called plasma

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Blood

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  1. Blood

  2. Components • Blood is the only fluid tissue in the body • Blood consists of living blood cells, called formed elements, suspended in a nonliving fluid called plasma • When spun in a centrifuge, the erythrocytes, or red blood cells, sink to the bottom. Their main function is oxygen transport. • Superior to this is the buffy coat, containing leukocytes and platelets, which prevent infection • Superior to this is the whole blood. Erythrocytes Buffy Coat

  3. Physical Characteristics and Volume • Blood is a sticky, opaque fluid with a metallic taste • Oxygen rich blood has a scarlet color, while oxygen poor blood has a dull red color • Blood is heavier than water, because of the formed elements • Blood has a pH of between 7.35 and 7.45 • Typical blood temperature is about 100.4 degrees • Blood makes up about 8% of body weight

  4. Plasma • Plasma is the liquid part of the blood • It is straw colored and is about 90% water • Plasma consists of over 100 dissolved substances such as nutrients, salts, hormones, and plasma proteins (most abundant) • Plasma helps to distribute heat evenly throughout the body The yellow substance is plasma

  5. The Formed Elements: Erythrocytes (RBC’s) • Function: carry oxygen in blood to all cells of the body • They are anucleate and contain very few organelles • They carry hemoglobin (Hb), which transports the bulk of oxygen carried in the blood • Shaped like biconcave disks • Normally about 5 million cells/mm3 blood • 1 RBC contains 250 million Hb molecule, which each carry 4 oxygen molecules • Males have slightly more RBC’s

  6. Erythrocyte Abnormalities: Anemia • A decrease in oxygen carrying ability, can happen for various reasons such as: • Decrease in RBC number: due to hemorrhage, infection, lack of Vitamin B12, destruction of bone marrow due to cancer, radiation, or certain medications • Inadequate hemoglobin content in RBC’s (iron deficiency anemia) • Abnormal hemoglobin in RBC’s (sickle cell anemia) Sickle cell anemia

  7. The Formed Elements: Leukocytes (WBC’s) • About 1 WBC for every 1000 RBC’s • Make up less than 1% of total blood volume • Contain nuclei and usual organelles • Have ability to slip in and out of blood vessel, diapedisis. Serves as transportation • Can also locate areas of tissue damage and infection in the body by responding to certain chemicals that diffuse from the damaged cells, called positive chemotaxis

  8. Leukocytes (cont.) • WBC’s move through tissue space using ameboid motion • By following the diffusion gradient, they pinpoint areas of damage and rally in large numbers to destroy the microorganisms or dead cells. • When WBC’s move into action, your body increases the numbers rapidly • They are classified into two groups depending on whether or not they have visible granules

  9. Classification of Leukocytes Neutrophils • Granulocytes: have granules, lobed nuclei. • Neutrophils: multi-lobed nucleus; cytoplasm stains pink, avid phagocytes at sites of acute infection • Eosinophils: blue-red nucleus, large brick-red granules, numbers increase during allergies and infections from parasitic worms (tapeworm) • Basophils: rare, contain large histamine containing granules that stain dark blue Eosinophils Basophils

  10. Classification of Leukocytes • Agranulocytes: lack visible cytoplasmic granules; normal nuclei • Lymphocytes: have large, dark purple nucleus that occupies most of the cell; play an important role in immune response • Monocytes: largest WBC’s; kidney-bean shaped nucleus; important in fighting chronic infections, such as tuberculosis Lymphocytes Monocytes

  11. The Formed Elements:Platelets • Fragments of multinucleate cells called megakarocytes, which pinch of platelet pieces, which seal themselves off from the surrounding fluid • Small, darkly staining, irregularly shaped bodies • Normal count is about 300,000/mm3 • Needed for the clotting process that occurs in plasma when blood vessels are ruptured or broken Tiny dots are thrombocytes (t)

  12. Hematopoiesis • Blood cell formation • Occurs in red bone marrow; each type is produced in different numbers in response to changing body needs and stimuli. After maturation, they are discharged into the blood • All formed elements arise from a common type of stem cell, the hemocytoblast, which resides in the red bone marrow. • Their development differs and once a cell is committed to a specific pathway it cannot change. Hemocytoblasts

  13. Hematopoiesis (RBC’s) • The hemocytoblast forms two types of descendants: the lymphoid stem cells, which produce lymphocytes, and the myeloid stem cell, which can produces all other classes of formed elements. • Because RBC’s are anucleate, they can’t make proteins, grow, or divide. As they age, they become more rigid and begin to fall apart in about 100 to 120 days, when they become eliminated by phagocytes in the spleen, lever, and other body tissues

  14. Hematopoiesis (RBC’s cont.) • Lost cells are replaced by division of hemocytoblasts in the red bone marrow. • The developing RBCs divide many times and then begin synthesizing huge amounts of hemoglobin. • Suddenly, when enough hemoglobin has been accumulated, the nucleus and most organelles are ejected and the cell collapses inward, resulting in an immature RBC, still containing RER • These enter bloodstream and within 2 days eject remaining RER to become full-functioning RBC’s

  15. More Hematopoiesis, Hooray! • The rate of erythrocyte production is controlled by a hormone called erythropoietin; produced in kidneys; numbers increase when blood oxygen levels decline; target the red bone marrow • Formation of white blood cells (WBC’s): certain stimulating factors and interleukins prompt red bone marrow to turn out leukocytes and also marshal up an army of WBCs to ward off attacks. • They are released in response to specific chemical signals in the enviornment. • Platelets: thrombopoietin accelerates production.

  16. Hemostasis • Hemostasis is the stopping of blood flow; it involves many substances present in plasma, as well as some that are released by platelets and injured tissue cells; involves 3 major phases, which occur in a rapid sequence. • They can be seen in motion, here… http://www.mhhe.com/biosci/esp/2002_general/Esp/folder_structure/tr/m1/s7/trm1s7_3.htm

  17. Steps of Hemostasis • 1.Platelet plug forms: platelets are repelled by an intact endothelium, but when it is broken so that the underlying collagen fibers are exposed, the platelets become sticky and cling to the damaged site. The anchored release chemicals that attract more platelets to the site, and as more pile up, the platelet plug is formed.

  18. Steps of Hemostasis • 2.Vascular spasms occur: the anchored platelets release serotonin, which causes the blood vessels to go into spasms; the spasms narrow the blood vessel at that point, decreasing blood loss until clotting can occur. • Other factors causing vessel spasms include direct injury to the smooth muscle cells and stimulation of local pain receptors.

  19. Steps of Hemostasis • 3.Coagulation events occur • The injured tissues release tissue factor (TF), which plays a role in clotting • PF3, a phospholipid coats the platelets, interacts with TF, Vit. K, other clotting factors, and Ca2+, to activate the clotting cascade • This prothrombin activator converts prothrombin, present in the plasma, to thrombin, an enzyme.

  20. Hemostasis (cont.) • Normally, blood clots within 3-6 minutes; once the cascade begins, the triggering factors are rapidly inactivated, so to prevent widespread clotting. • Applying gauze and pressure to the wound greatly aid the clotting process. • The more tissue factor released, the faster the clot.

  21. Blood Disorders • Thrombus: a clot that develops and persists in an unbroken blood vessel • Embolus: a clot that broke away from the vessel wall and floats freely in the bloodstream • Hemophilia: Hereditary; several different disorders resulting from a lack of any substance needed for clotting; get synthetics injected into them to stop the bleeding CHOLESTEROL IN BLOOD VIDEO

  22. Blood Groups • The plasma membranes of RBCs bears genetically determined proteins, which identify each person as unique • Antigen: substance that the body recognizes to release antibodies or use other means to mount a defense against it • Binding of antibodies to the antigens causes the RBCs to clump, called agglutination, which leads to clogging of small blood vessels throughout the body.

  23. Blood Groups (cont.)

  24. Blood Groups (cont.) BLOOD TRANSFUSIONS VIDEO

  25. Sources • http://uhaweb.hartford.edu/BUGL/RBCs.jpg • http://www.thecrookstoncollection.com/Collection/medslides/Slides/CGL-Buffy-Coat.jpg • http://www.dreddyclinic.com/images/ph_scale.jpg • http://www.uoguelph.ca/zoology/devobio/miller/013633fig6-14.gif • http://www.uoguelph.ca/zoology/devobio/miller/013631fig6-15.gif • http://www.sciencemuseum.org.uk/exhibitions/genes/images/1-3-5-1-4-2-1-3-1-0-0.jpg • http://www.wadsworth.org/chemheme/heme/microscope/pix/cmlmyeloblast_nw.jpg • http://www.ctdslab.co.uk/images/felineneutlarge.jpg • http://www.funsci.com/fun3_en/blood/blood_03.jpg • http://cellbio.utmb.edu/microanatomy/blood/basophil.JPG • http://mmserver.cjp.com/images/image/4303037.jpg • http://mmserver.cjp.com/images/image/0144088.jpg • http://www.wadsworth.org/chemheme/heme/microscope/pix/platelets_nw.jpg • http://content.answers.com/main/content/wp/en/thumb/b/b8/180px-Gray72.png • http://content.answers.com/main/content/wp/en-commons/2/20/Illu_blood_cell_lineage.jpg • http://www.sciencecases.org/baby_joe/hematopoiesis.gif • http://www.hemophiliagalaxy.com/patients/images/REC0057.jpg • http://www.ncbi.nlm.nih.gov/books/bookres.fcgi/stryer/ch10f37.gif • http://www.made-in-china.com/image/2f0j00fIRETCQPjaKMM/Conforming-Elastic-Bandage-Gauze-.jpg

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