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Marieb’s Human Anatomy and Physiology Marieb w Hoehn. Chapter 17 Blood Lecture 1 Part 2: White Blood Cells and Platelets. White Blood Cells. leukocytes protect against disease interleukins and colony-stimulating factors stimulate development in red bone marrow. granulocytes
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Marieb’s Human Anatomy and Physiology Marieb w Hoehn Chapter 17 Blood Lecture 1 Part 2: White Blood Cells and Platelets
White Blood Cells • leukocytes • protect against disease • interleukinsand colony-stimulating factors stimulate development in red bone marrow • granulocytes • neutrophils • eosinophils • basophils • agranulocytes • lymphocytes • monocytes ‘phils’ are filled with granules!
Neutrophils • light blue granules in acid-base stain • lobed nucleus • other names • segs • polymorphonuclear leukocyte (PMNs) • bands (young neutrophils) • first to arrive at infections • phagocytic • *55% - 65% of leukocytes (most numerous type of WBC) • elevated in bacterial infections Figure from: Hole’s Human A&P, 12th edition, 2010
Basophils Figure from: Hole’s Human A&P, 12th edition, 2010 • deep blue granules from basic stain • release histamine andheparin in allergic reactions (similar to mast cells) • less than 1% of leukocytes
Eosinophils Figure from: Hole’s Human A&P, 12th edition, 2010 • deep red granules in acid stain • bilobed nucleus • participate in allergic reactions • defend against parasitic worm infestations • 1% - 3% of leukocytes • elevated in worm infestations and allergic reactions, collagen diseases, diseases of spleen
Monocytes Figure from: Hole’s Human A&P, 12th edition, 2010 • largest blood cell • agranulocyte • kidney-shaped or oval nuclei • leave bloodstream to become macrophages • 3% - 9% of leukocytes • elevated in typhoid fever, malaria, tuberculosis, viral infections, inflammation
Lymphocytes • about the size of RBC • agranulocytic • large spherical nuclei • thin rims of cytoplasm • T cells • B cells • NK cells • important in immunity • 25% - 33% of leukocytes • produce antibodies (B) • decreased T Cells in AIDS Figure from: Hole’s Human A&P, 12th edition, 2010
Diapedesis • Diapedesis - leukocytes squeeze through capillary walls to enter tissue space outside the blood vessel Figure from: Hole’s Human A&P, 12th edition, 2010
White Blood Cell Counts • number of WBCs per mm3 of blood • 5,000 – 10,000 per mm3 (or μl) of blood • leukopenia(-penia = deficiency of cell number) • low WBC count • typhoid fever, flu, measles, mumps, chicken pox, AIDS • leukocytosis(-cytosis = increase in cell number) • high WBC count • acute infections, vigorous exercise, great loss of body fluids • differential WBC count • lists percentages of types of leukocytes • may change in particular diseases
Origin of Blood Cells All formed elements of blood arise from a common hematopoietic pluripotent stem cell (a hemocytoblast) in the red bone marrow Figure from: Hole’s Human A&P, 12th edition, 2010
Blood Platelets • called thrombocytes when nucleated (in birds) • cell fragments of megakaryocytes • membrane bound • 150,000 – 500,000 per mm3 of blood (average ≈ 350,000 per µl) • help control blood loss from broken vessels
Review To remember relative % of leukocytes from most to least numerous: “Never Let Monkeys Eat Bananas”