Red blood cells The fundamental stimulus for production of red blood celf( erythropoiesis) is erythropoietin(红细胞生成素), a glycoprotein produced by the kidneys in response to renal tissue hypoxia. Other hormones, such as corticosteroids, thyroid hormone and androgens stimulate the production or release of erythropoietin but have no intrinsic erythropoietic activity. The average lifespan of a circulating erythrocyte is 110 120 days in the dog and 68 days in the cat. Aged or damaged red cells are removed primarily by macrophages in the liver, spleen and bone marrow
Red blood cells The fundamental stimulus for production of red blood cells (erythropoiesis) is erythropoietin(红细胞生成素）, a glycoprotein produced by the kidneys in response to renal tissue hypoxia. Other hormones, such as corticosteroids, thyroid hormone and androgens, stimulate the production or release of erythropoietin but have no intrinsic erythropoietic activity. The average lifespan of a circulating erythrocyte is 110- 120 days in the dog and 68 days in the cat. Aged or damaged red cells are removed primarily by macrophages in the liver, spleen and bone marrow
Neutrophils The production of neutrophils, eosinophils and basophils is termed granulopoiesiS. The neutrophils in the bloodstream either circulate freely(the circulating pool) or adhere to the vascular endothelium (the marginal pool). In the dog the marginal pool and the circulating pool are approximately equal in size, whilst in the cat the marginal pool is two to three times larger than the circulating pool. There is a continual exchange of cells between these two pe oolS。 The half-life of circulating neutrophils is only 6-14 hours, after which time they leave the circulation and pass into the tissue pool. The circulating time is shortened during acute infections as neutrophils pass to the site of infection in the tissues. The main function of the neutrophil is the phagocytosis of pyogenic bacteria
Neutrophils The production of neutrophils, eosinophils and basophils is termed granulopoiesis. The neutrophils in the bloodstream either circulate freely (the circulating pool) or adhere to the vascular endothelium (the marginal pool). In the dog the marginal pool and the circulating pool are approximately equal in size, whilst in the cat the marginal pool is two to three times larger than the circulating pool. There is a continual exchange of cells between these two pools. The half-life of circulating neutrophils is only 6-14 hours, after which time they leave the circulation and pass into the tissue pool. The circulating time is shortened during acute infections as neutrophils pass to the site of infection in the tissues. The main function of the neutrophil is the phagocytosis of pyogenic bacteria
lymphocytes Lymphoid primitive stem cells divide and differentiate into pre-B lymphocytes and pre-T lymphocytes in the bone marrow Pre-T lymphocytes mature and proliferate into T cells in the thymus Pre-B cells proliferate in the bone marrow and migrate to peripheral lymphoid organs(spleen and lymph nodes) where further proliferation takes place. Platelets Platelets are produced from the cytoplasm of megakaryocytes Once in the circulation, platelets survive for 8-12 days Up to 20-30% of circulating platelets can be sequestered in the spleen; the figure may be a high as 90% if there is splenomegaly. Old or damaged platelets are removed from the circulation by the spleen, liver and bone marrow
Lymphocytes Lymphoid primitive stem cells divide and differentiate into pre-B lymphocytes and pre-T lymphocytes in the bone marrow. Pre-T lymphocytes mature and proliferate into T cells in the thymus. Pre-B cells proliferate in the bone marrow and migrate to peripheral lymphoid organs (spleen and lymph nodes) where further proliferation takes place. Platelets Platelets are produced from the cytoplasm of megakaryocytes Once in the circulation, platelets survive for 8-12 days. Up to 20-30% of circulating platelets can be sequestered in the spleen; the figure may be a high as 90% if there is splenomegaly. Old or damaged platelets are removed from the circulation by the spleen, liver and bone marrow
ROUTINE HAEMATOLOGY The complete blood count is an integral part of the diagnostic investigation of any systemic disease process. It consists of two components A quantitative examination of the cells, including packed cell volume(PCv) total red cell count (RBC) total white cell count(WBC differential white cell count platelet count mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration(MCHC), total plasma protein concentration. A qualitative examination of blood smears for changes in cellular morphology
ROUTINE HAEMATOLOGY The complete blood count is an integral part of the diagnostic investigation of any systemic disease process.It consists of two components: A quantitative examination of the cells, including : packed cell volume (PCV) total red cell count (RBC) total white cell count(WBC) differential white cell count platelet count mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), total plasma protein concentration. A qualitative examination of blood smears for changes in cellular morphology
ROUTINE HAEMATOLOGY Table 1 reference values for red cell indices Dogs Cats Total red blood cells(x10 /L) 5.5~8.5 5.0~10.0 Haemoglobin(g/dl) 12.0~18.0 8.0~15.0 PCV(L/L) 0.37~0.55 0.26~0.45 MCV(1) 60.0~77.0 39.0~55.0 MCH (Pg) 19.5~24.5 12.5~17.5 MCHC(g/dl) 32.0~37.0 30.0~36.0
Table 1 Reference values for red cell indices Dogs Cats Total red blood cells(x1012/L) 5.5~8.5 5.0~10.0 Haemoglobin(g/dl) 12.0~18.0 8.0~15.0 PCV (L/L) 0.37~0.55 0.26~0.45 MCV (fl) 60.0~77.0 39.0~55.0 MCH (pg) 19.5~24.5 12.5~17.5 MCHC (g/dl) 32.0~37.0 30.0~36.0 ROUTINE HAEMATOLOGY