Blood

• White blood cells:

  • Are leukocytes
  • Protect against disease
  • WBC hormones are interleukins and colony-stimulating factors which stimulate development
• There are five types of WBCs in two categories:

  Granulocytes

  • Neutrophils
  • Eosinophils
  • Basophils

  Agranulocytes

  • Lymphocytes
  • Monocytes
• Eosinophils

  • Deep red granules in acid stain
  • Bi-lobed nucleus
  • Moderate allergic reactions
  • Defend against parasitic worm infestations
  • 1% - 3% of leukocytes
  • Elevated in parasitic worm infections and allergic reactions
• Basophils

  • Deep blue granules in basic stain
  • Release histamine
  • Release heparin
  • Less than 1% of leukocytes
  • Similar to eosinophils in size and shape of nuclei
• Monocytes

  • Largest of all blood cells
  • Spherical, kidney-shaped, oval or lobed nucle
  • May leave bloodstream to become macrophages
  • 3% - 9% of leukocytes
  • Phagocytize bacteria, dead cells, and other debris
• Lymphocytes

  • Slightly larger than RBC
  • Large spherical nucleus surrounded by thin rim of cytoplasm
  • T cells and B cells
  • Both important in immunity
  • B cells produce antibodies
  • 25% - 33% of leukocytes
• Red blood cell

  • Biconcave disk; no nucleus; contains hemoglobin, which colors the cell red; 7.5 um in diameter
  • Transports oxygen and carbon dioxide
• White blood cells

  • Spherical cells with a nucleus; white in color because they lack hemoglobin
  • Five types of white blood cells, each with specificmfunctions
• Neutrophil

  • Nucleus with two to four lobes connected by thin filaments; cytoplasmic granules stain a light pink or reddish purple; 10-12 um in diameter
  • Phagocytizes microorganisms and other substances
• Basophil

  • Nucleus with two indistinct lobes; cytoplasmic granules stain blue-purple; 10-12 um in diameter
  • Releases histamine, which promotes inflammation, and heparin, which prevents clot formation
• Eosinophil

  • Nucleus often bilobed: cytoplasmic granules stain orange-red or bright red; 11-14 um in diameter
  • Releases chemicals that reduce inflammation; attacks certain worm parasites
• Lymphocyte

  • Round nucleus; cytoplasm forms a thin ring around the nucleus; 6-14 um in diameter
  • Produces antibodies and other chemicals responsible for destroying microorganisms; contributes to allergic reactions, graft rejection, tumor control, and regulation of the immune system
• Monocyte

  • Nucleus round, kidney-shaped, or horseshoe-shaped; contains more cytoplasm than does lymphocyte; 12-20 um in diameter
  • Phagocytic cell in the blood; leaves the blood and becomes a macrophage, which phagocytizes bacteria, dead cells, cell fragments, and other debris within tissue
• Platelet

  • Cell fragment surrounded by a plasma membrane and containing granules: 2-4 jum in diameter
  • Forms platelet plugs; releases chemicals necessary for blood clotting