BLOOD CELLS

LEC.2 Nov.2016

Objectives Types of blood cells 2.Hemopoiesis(Hematopoiesis) 3.Red Blood Cells(RBC)

BLOOD CELLS Blood cells makes about 45 % of the total blood volume( 5600mL) i.e. 2500 mL. Blood cells are the solid phase plasma. Types: a- Red Blood Cells ( RBC’s ) or erythrocytes. b- White Blood Cells ( WBC’s ) or leukocytes. c.Cell Fragments called platelets or thrombocytes

Hemopoiesis or Hematopoiesis is the process of blood cells production. Erthropoiesis: is the proliferation & differentiation of RBC’s or erythrocytes. Leukopoiesis: is the development of WBC’s or leukocytes. Thrombopoiesis: is the development of platelets or thrombocytes.

The bone marrow ---- multipotent uncommitted stem cells (pluripotential stem cells ) ---- differentiate ------committed stem cells ( progenitor cells ) ----- differentiated into various differentiated types of blood cells

1.Proerythroblasts ( pronormoblast ): erythrocytes develop. 2.Myeloblasts: from which granulocytes ( Neutrophil, eosinophils & basophile ) develop. 3.Lymphoblasts: From which lymphocytes ( T & B-lymphocytes ) develop. 4.Monoblast: from which monocytes develop. 5.Megakaryoblasts: from which platelets or thombocytes develop.

Red Blood Cells (RBC’ s( Or Erythrocytes

About 95 % of the volume of the blood cells consists of erythrocytes. Red blood cells or erythrocytes About 95 % of the volume of the blood cells consists of erythrocytes. No nuclei in RBC. Erythropoiesis: is the process of RBC’s production. .

Regulation of red blood cell production: Role of erythropoietin. The rate of erythropoiesis is regulated by a humoral agent known as erythropoietin. 90% of the erythropoietin is formed in the kidneys & 10% in the liver. The function of this hormone is to stimulate committed stem cells to differentiate into proerythroblasts i.e. stimulate the synthesis of messenger RNA. The main factor that cause the release of erythropoietin is hypoxia therapy.

Maturation of Erythrocytes Cell division requires two vitamins : Vitamin B12 Folic acid . The type of anemia due to lack of folic acid & vit. B12 is called megaloblastic anemia

Morphology Size :diameter of 7.2 to 7.9 micrometers -- edges 2.5 micrometers thicker than the center --about 1 micrometers. shape--biconcave discs Content—hemoglobin, ATPase, & enzyme carbonic anhydrase,water

Red blood cell Count—5400000 in male &4700000 in female Anemia--RBC’s counts are less than normal value Polycythemia--- RBC’s count is more than normal Life span of the RBC: average of 120 days in males & 110 days in females

Packed Cell Volume (PVC) or hematochrit (hcr)---volume of RBC’s in 100ml (dl) of blood. in male is 47%female is 42%. anemia PCV is less than normal while in Polycythemia RCB is greater than normal value Hemolysis of RBC

Total blood Volume (TBV) TBV = plasma volume + red cell volume About 55% of this volume is plasma (3080 ml), and about 45% of this volume is packed cell volume (2520 ml). TBV in the average adult is 4-5 L in female & 5-6 L in adult males.