Chapter \^ 



Hematologic Elements 

 and Related Tissues 



Blood is a fluid {plasma) that contains suspended in it cells and frag- 

 ments of cytoplasm. The fragments are platelets and the cells are either 

 red cells (erythrocytes) or white cells (leukocytes). The erythrocytes are 

 nonnucleated, but 90% of their solid content is made up of hemoglobin, 

 a protein. Leukocytes are all nticleated and are classified as five different 

 kinds. The granular leukocytes have a granular cytoplasm and include 

 the neutrophils, eosinophils and basophils. The nongranular leukocytes 

 have nongranular cytoplasm and are the lymphocytes and monocytes. 

 The granular leukocytes are named according to the afimity of their 

 granules for certain types of stains — neutral, acid (eosin), and basic. The 

 term polymorphs is often applied to neutrophils because of their many- 

 formed or many-lobed nuclei. 



Bone marrow is a hemopoietic (blood forming) tissue and is described 

 as either red or yellow. The red marrow is red due to great numbers of 

 red blood cells in various stages of formation; it is actively producing 

 blood cells. Yellow marrow contains large quantities of fat; it is not 

 actively manufacturing blood cells but is storing fat. Yellow marrow 

 nonetheless retains the potential to resume production of blood cells. 

 [Rejerence: Ham, 19^7) 



Blood cells and fluid may become parasitized in various ways, as with 

 malaria, trypanosomes, inclusion bodies of various diseases, such as rick- 



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