Hematology L1 PDF

HAEMSTOPOIESIS AND BLOOD Dr.Jenan.Y.Taha Assisstance prof./Hematology  Hematology the study of the nature, function, and diseases of the blood and of blood-forming organs. Blood is a constantly circulating fluid providing the body with nutrition, oxygen, a...

HAEMSTOPOIESIS AND BLOOD Dr.Jenan.Y.Taha Assisstance prof./Hematology  Hematology the study of the nature, function, and diseases of the blood and of blood-forming organs. Blood is a constantly circulating fluid providing the body with nutrition, oxygen, and waste removal. Blood is mostly liquid, with numerous cells and proteins suspended. The average person has about 5 liters of blood (8% of body weight )  Components of blood ⚫Blood cells (45%) ⚫ Plasma (55%) ⚫ Type of cells Red blood cells (erythrocytes) White blood cells (leucocytes) Platelets (thrombocytes)  Plasma A. 9 1% WATER : THIS ACTS AS ASOLVENT & SUSPENDING MEDIUM FOR BLOOD COMPONENT. B. 2% OTHER SOLUTES SUCH AS : -ions (involved in osmosis, membrane potential & and acid-base balance). 2-nutrients (as a source of energy). 3- Vitamins (promote enzyme activity). 4- Gases (such as O2 necessary for aerobic respiration, and CO2 waste product of aerobic respiration). 5-regulatory substances (such as hormones). 6- Waste products (such as urea, uric acid, etc which are excreted by the kidneys.  C-. (7%) PLASMA PROTEINS : PLASMA: IS A COLLOIDAL SOLUTION, WHICH IS ALIQUID CONTAINING SUPENDED SUBSTANCE. MOS T OF THE SUSPENDED SUBSANCES ARE PLASMA PROTEINS , WHICH INCLUDE ALBU MIN, GLOBULINS , & FIBRINOGEN. ORIGIN OF PL ASMA PR OTEINS: MOST OF THE PLASMA PROTEINS ARE SYNTHESIZED IN THE LIVER EXCEPT CIRCUATING ANTIBOD IES OR IMMUNOGLOBUL N'S WHICH ARE MANUFACTURED FROM B-LYMPHOCYTES  SERUM If whole blood is allowed to clot and the clot is removed, the remaining fluid is called serum. Serum has essentially the same composition as plasma except that its clotting factors: fibrinogen (factor I), prothrombin (factor II), factor V, and antihemophilic factor VIII have been removed , So serum may be defined as plasma minus clotting factors (I, II, V, and VIII)  FUNCTION OF THE BLOOD transporting oxygen and nutrients to the lungs and tissues forming blood clots to prevent excess blood loss carrying cells and antibodies that fight infection bringing waste products to the kidneys and liver, which filter and clean the blood regulating body temperature  Hemopoiesis Hemo refers to blood cells Poiesis is the development or production The word hemopoiesis refers to the production and development of all blood cells. Types - Erythrocytes (erythropoiesis) - Leucocytes (leucopoeisis) - Thrombocytes (thrombopoiesis)  Unlike some organ systems that form in early life and are not continually replaced, turnover and replenishment of the hematopoietic system continue throughout life. The cells of the blood have definite lifespans, which vary depending on the cell type. In humans, granulocytes and platelets have lifespans of only a few days, whereas some lymphocytes can exist for many months. Cells are replaced as the older cells are removed and the newly formed, mature cells are added. The numbers of the various cell types in the blood are normally kept in relatively constant ranges.  The bone marrow is the most important site from 6 months of fetal life. * During normal childhood and adult life the marrow is the only source of new blood cells. * In infancy all the bone marrow is totally hemopoietic but during childhood there is progressive fatty replacement of marrow throughout the long bones so that in adult life hemopoietic marrow is confined to the central skeleton and proximal ends of the femurs and humeri.  BONE MARROW Bone marrow found in the medullary canal of long bones& cavities of cancellous (spongy bone ) Two types : Red bone marrow due blood. Yellow bone marrow due fat cells. IN newborns all bone marrow is red Extra medullary Normal bone marrow can expand 6—8 time its normal capacity to compensate blood cells loss( acute anaemia) with normal nutrients and environment until deficiency appear. Extra medullary hemopoiesis : hemopoiesis confined to sites out of normal red bone marrow mostly in the ( liver and spleen). Occur in chronic hemolytic anaemia with failure of the normal red marrow to compensate the blood loss. It cause increase size of these organs (hepato—splenomegaly). All cellular blood components are derived from hematopoietic stem cells The body continually manufactures new blood cells to replace old ones. About 1 percent of the body’s blood cells must be replaced every day. This hemopoietic stem cell (HSC) is rare, perhaps 1 in every 20 million nucleated cells in bone marrow White blood cells have the shortest life span, sometimes surviving just a few hours to a few days, while red blood cells can last up to 120 days or so. Stem cells - Ability to give rise to new stem cells (self renewal) - Ability to differentiate into any blood cell lines (pluripotency) They grow and develop in the red bone marrow Types of stem cells - Pluripotent stem cells Give rise to both myeloid and lymphoid cells - Myeloid stem cells Generate myeloid cells (blood cells) - Lymphoid stem cells Give rise to lymphocytes In order to form blood cells, pluripotent stem cells in red bone marrow produce myeloid and lymphoid stem cells Myeloid stem cells begin their development in red bone marrow and give rise to red blood cells, platelets, monocytes, neutrophils, eosinophils, and basophils. Lymphoid stem cells begin their development in red bone marrow but complete it in lymphatic tissues; they give rise to lymphocytes Hematopoietic regulating factors 1-Several hormones regulate the process Erythropoietin, hormone produced by kidneys that stimulate formation pf red blood cells (RBCs) Thrombopoietin, produced by the liver, stimulate the formation of platelets - Two important cytokines stimulate white blood cell formation (WBC) are colony-stimulating factors (CSFs) and interleukins  2-Nutrients support : minerals (IRON) , vitamins (B12, folic acid, ), Amino acids. 3-Normal bone marrow environment and supportive tissue.( macrophages, fatty cells and fibroblast ). Macrophages Has different functions: a. storage Iron in the bone marrow b. removal of the aged red blood cells c. Release of cytokines and control hemopoiesis  Assessment of Hemopoiesis 1. Htc and Hb (PCV, hemoglobin), 2, CBC: erythrocytes count, leukocytes count, platelets count 3. Blood film ( for cells morphology) 4. Reticulocytes count 5. Bone marrow aspirate BLOOD FILM NORMAL BLOOD FILM reticulocyte stain