Leucocytes (white blood corpuscles)
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LEUCOCYTES (white blood corpuscles)
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These are nucleated, (true cells) and may be divided into non-granular (agranulocytes) and granular (granulocytes) varieties.
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The cytoplasm of granular leucocytes shows numerous granules. In many, these granules are fine and slightly refractive but in others they are coarse and highly refractive.
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Total number of leucocytes in thousand Per cubic mm.
Chicken
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19.8
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Cat
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17.2
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Swine
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14.9
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Goat and guinea pig
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12
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Dog
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11.3
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Sheep
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9.2
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Horse
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9
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Man
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9
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Ox
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8
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Rabbit
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8
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Granulocytes:
Dog
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74
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Man
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72
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Cat
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59
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Horse
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58
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Swine
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53
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Guinea pig and rabbit
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40
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Goat
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35
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Ox
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30
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Chicken
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24.4
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Sheep
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24
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Ox
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10
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Guinea pig
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8
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Horse
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7
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Goat
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5.8
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Cat
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5
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Sheep
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4
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Swine
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4
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Dog
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2
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Chicken
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1.9
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Rabbit
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1.5
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Basophils
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These are rare in adult blood being only 0.5 percent of leucocytes except in the chicken (3 percent). Their size is 8 to 10 microns. The nucleus is large irregularly polymorphous. The coarse granules are basophilic, intermediate in size between eosinophil and neutrophil types and are soluble in water. They resemble the mast cells of connective tissue.
Non granular leucocytes or agranulocytes:
Sheep
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68
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Chicken
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62
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Goat
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57
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Rabbit
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55
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Ox
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52
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Guinea pig
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45
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Swine
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38
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Horse
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28
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Man and dog
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20
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Monocytes
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These are large cells, size varying from 12 to 15 microns, but they may occasionally be up to 20 microns. The nucleus is ovoid, kidney or horse-shoe shaped and eccentrically placed. It stains less intensely than lymphocytes. Cytoplasm is basophilic and abundant. They migrate through the capillary wall into the surrounding connective tissue, become actively phagocytic and transform into macrophages, indistinguishable from the macrophages present in the connective tissue. They serve to combat certain types of bacterial infection like tuberculosis.
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Number of monocytes in percentage of total number of leucocytes.
Chicken
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9.4
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Ox
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7
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Guinea pig
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6
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Horse
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5
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Man
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5
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Swine
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4
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Sheep
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3
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Rabbit and cat
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2.5
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Goat
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2.2
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Blood Platelets
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They are colorless about 3 microns biconvex discs but appear spindle shaped when seen sideways.
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They have no nucleus. They show a central granular mass which stains deeply with basic stains called the chromatomere and a peripheral hyaline lightly stained zone called the hyalomere.
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In mammals they are not cells but are only fragments of cells derived from the giant cells in red marrow.
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Birds and other lower vertebrates have true thrombocytes which are nucleated and have basophilic cytoplasm.
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The platelets play an important role in coagulation of blood.
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Last modified: Friday, 20 August 2010, 12:22 PM