Blood supplies cells with water, electrolytes, nutrients, and hormones and removes waste products. The cellular elements supply oxygen (RBCs Red Blood Cells in Animals The function of RBCs is to carry oxygen to the tissues at pressures sufficient to permit its rapid diffusion. This is accomplished through the following mechanisms: a carrier molecule, hemoglobin... read more ), protect against foreign organisms and antigens (WBCs White Blood Cells in Animals The principal function of phagocytes is to defend against invading microorganisms by ingesting and destroying them, thus contributing to cellular inflammatory responses. There are two types... read more ), and initiate coagulation (platelets Platelets in Animals Platelets form the initial hemostatic plug whenever hemorrhage occurs. They also are the source of phospholipid, which is needed for the interaction of coagulation factors to form a fibrin clot... read more ). Because of the diversity of the hematopoietic system, its diseases are best discussed from a functional perspective. Function may be classified as either normal responses to abnormal situations (eg, leukocytosis and left shift in response to inflammation) or primary abnormalities of the hematopoietic system (eg, pancytopenia from marrow failure). Furthermore, abnormalities may be quantitative (ie, too many or too few cells) or qualitative (ie, abnormalities in function). (Also Veterinary.see The Biology of the Immune System The Biology of the Immune System read more .)
Also see pet health information regarding an introduction to blood Introduction to Blood Disorders of Dogs Blood cells form and develop mostly in the bone marrow, that is, the tissue located in the cavities of bones. Blood performs a variety of important functions as it circulates throughout the... read more .