486 Animal Biology 



lymphocytes contribute to the repair of wounds by connective tissue for- 

 mation and give origin to the monocytes. A summary of the various 

 types of blood corpuscles and blood platelets is given in tables so they 

 may be compared and contrasted more easily. A decrease in the number 

 of leucocytes is called leucopenia (lu ko -pe' ne ah) (Gr. leukos, white; 

 penes, poor) and an increase is leucocytosis (lu ko si -to' sis) (Gr. kytos, 

 cell). 



Summary of Leucocytes 



TYPE 



GRANULOCYTES 



1. Neutrophils 



2. Eosinophils 

 (Acidophils) 



3. Basophils 



AGRANULOCYTES 



1. Lymphocytes 



2. Monocytes 



PER CENT 

 OF TOTAL 



LEUCO- 

 CYTE 



COUNT 



65-75 



2-5 



0.5 



20-25 



3-8 



DIAM- 

 ETER 

 IN 

 MI- 

 CRONS 



10-12 



12 



10 



8 



15 



CHARACTERISTICS 



Fine light blue cytoplasmic granules, 3 to 

 5 lobed nucleus 



Bright red cytoplasmic granules (Wright's 

 blood stain), nucleus with 2 lobes 



Large, dark purplish-blue cytoplasmic 

 granules (Wright's stain), irregular 

 nucleus, often S-shaped 



Thin layer of nongranular, robin's-egg 

 blue cytoplasm (Wright's stain), large 

 bright purple nucleus 



hick layer of nongranular cytoplasm, 

 large horseshoe- or kidney-shaped, pur- 

 ole nucleus (Wrierht's stain) 



Clotting (Coagulation) of Human Blood 



The chemical process which blood undergoes when it clots is quite 

 complicated. Several theories have been proposed to explain the proc- 

 ess. A brief summary will illustrate the more important stages. 



Blood 



Body I 



Tissues Platelets 



(by disintegration) 



(Injured) 



Plasma 



Vitamin K 



(in iver) 



Calcium 



Fibrinogen 



Thromboplastin + Prothrombin + Calcium — ^ Thrombin 



(Cephalin) Thrombin + Fibrinogen — > Fibrin 



