Blood Composition And Functions PDF

MDP 10108: Foundation Block Haematology Composition &  ...

MDP 10108: Foundation Block Haematology Composition &   Study of blood cells and coagulation. Concentration, structure and function Functions of Blood  of cells in blood. Cell precursors in bone marrow. Tay Siow Phing  Chemical constituents of plasma and Department of Pathology serum. Faculty of Medicine & Health Science  Platelets and plasma proteins Universiti Malaysia Sarawak (UNIMAS) (haemostasis). 4 Nov 2024 1 2 Learning Objectives Blood is a ….. At the end of this lecture, students should be able to :  Describe the composition of the normal whole blood as a tissue,  Component of cardiovascular system. including the relative quantities of its cellular and plasma (heart, blood vessels, blood) components. Explain the basic structures and functions of the cellular  Part of circulatory system.  components. Discuss the functions of the plasma components.   Describe the major classes of plasma proteins (albumin, (cardiovascular + lymphatic systems) globulin, fibrinogen).  Discuss the differences between plasma and serum.  Specialised fluid connective tissue /  Describe the characteristic differences between platelets, erythrocytes and leucocytes. supportive tissue.  Describe the characteristic differences between the subtypes of (liquid portion + cellular portion) leucocytes. 3 4 Physical Characteristics Bone Marrow Aspiration  Red in colour (haemoglobin in red cells). To obtain:  Thicker , denser, more viscous than water.  Bone marrow aspirate (BMA)  ~ 38 ºC (slightly higher than body temperature).  Bone marrow biopsy (trephine)  pH 7.35 - 7.45 (average = 7.40) - slightly alkaline.  Blood volume: 4-6 L (~8% of total body weight). Diagnosing of white cell disorders ( male : 5-6 L, female : 4-5 L, newborn : 240 mL) (e.g. leukaemia, lymphoma) relies on  Density : Specific gravity = 1.045 - 1.065 a baseline bone marrow evaluation. (water = 1.000). 5 1  Sites of Production  Foetus – yolk sac, liver, spleen, red bone marrow.  Infants – red bone marrow (practically all bones).  Adults – red bone marrow (practically long bones, flat bones). e.g. skull, ribs, sternum, vertebrae, pelvis, upper half of sacrum, proximal ends of femur and humerus. 7 8 Formation, development and maturation of all blood cells Haemopoietic System Haemopoiesis / Hematopoiesis Consists of :  Erythropoiesis (red cells)  Bone Marrow  Liver  Leucopoiesis (white cells) Granulopoiesis /Myelopoiesis  Spleen (neutrophils, basophils, eosinophils)  Lymph Nodes Lymphopoiesis (lymphocytes)  Thymus Monopoiesis (monocytes) These tissues/organs involve in production, maturation  Thrombopoiesis / Megakaryopoiesis (platelets) and destruction of blood cells. 9 10 Haemopoiesis Haemopoietic Tree  Intramedullary Haemopoiesis Haemopoiesis within the bone marrow. Myeloid Lymphoid Stem Cells Stem Cells  Extramedullary Haemopoiesis Haemopoiesis outside the bone marrow (in the liver and spleen).  Most blood cells are continually dying and being replaced within hours, days or weeks.  All blood cells are originated from multipotent haemopoietic stem cells in the red bone marrow.  Myeloid stem cells develop into : - platelets, red blood cells. - neutrophils, eosinophils, basophils, monocytes.  Lymphoid stem cells develop into : - B lymphocytes, T lymphocytes, natural killer (NK) cells. 11 12 2  Factors That Control Haemopoiesis Composition of Blood  Oxygen.  Liquid portion (non-cellular elements) : 55%  Carbohydrates, proteins, fats. - Plasma (yellowish / straw coloured fluid).  Minerals (iron).  Vitamins (folate, vitamin B12).  Solid portion (formed or cellular elements) : 45%  Bone marrow microenvironment - Platelets (thrombocytes) - clear - Red blood cells (erythrocytes) - red. (endothelial cells, fibroblasts, adipocytes, - White blood cells (leucocytes) - clear. macrophages, extracellular matrix). - Stem cells - clear.  Cytokines (Interleukins: IL-1, IL-2, IL-3, IL-4, IL-5, IL-6).  Growth factors (c-kit ligand/stem cell factor, erythropoietin, thrombopoietin, GM-CSF, G-CSF, M-CSF). G = granulocyte; M = monocyte; CSF = colony stimulating factor 13 14 Plasma Water (91.5%) Proteins (7%)  Liquid part of the blood. Other Solutes (1.5%)  Non-cellular component.  Yellowish. Plasma  SG 1.025-1.029. Neutrophils (60-70%)  Volume ~3L (male > female). Buffy Coat Eosinophils (1-6%) Leucocytes Basophils (0-2%)  pH 7.36-7.44 (average = 7.40). Platelets Lymphocytes (20-40%)  Osmolarity = 285-300 mosm/L. Monocytes (2-10%)  90% water, 10% solutes (proteins, Erythrocytes Stem cells nutrients, electrolytes, wastes etc). 15 16 Plasma Proteins  Globulin (38%)  > 60 plasma proteins. - gamma () : antibodies or immunoglobulins,  Separated and identified by ultracentrifugation and produced during immune responses by electrophoresis. plasma cells (IgG, IgA, IgM, IgD and IgE).  Divided into: albumin, globulin, fibrinogen. - alpha (1, 2) and,beta ( 1,  2) :  Albumin (58%) transport lipid and fat-soluble vitamins, - the smallest, most abundant plasma protein. synthesized in the liver (LDL, HDL). - synthesized in the liver (hepatocytes). - colloidal oncotic/osmotic pressure (∵↓size, ↑amount).  Fibrinogen (4%) - protein reserve (source of amino acids). - synthesized in the liver (hepatocytes). - transport protein (hormones, fatty acids, drugs, metal ions). - essential for clotting. - acid-base balance. 17 18 3  Plasma Electrolytes Gases Nutrients  Oxygen (O2) Sodium 145 mmol/l  Carbon dioxide (CO2)  Glucose – energy Potassium 5  Nitrogen (N2)  Amino acids – protein synthesis Calcium 2.5  Fatty acids – cells, hormones, energy Magnesium 0.7  Vitamins Chloride 110  Minerals Bicarbonate 28 Phosphate 1 Wastes Sulphate 1  Urea Glucose 5 Regulatory Substances  Uric acid  Enzymes  Creatine, creatinine Urea 7  Hormones  Bilirubin Organic acids 3  Ammonia Proteins 1 19 20 Non-Cellular Elements Transportation (Liquid Portion)  Transport gases. (e.g. O2, CO2)  Transport nutrients. Plasma (e.g. water, ions) Serum Leucocytes (no fibrinogen)  Transport waste products Platelets (Buffy Coat) (e.g. urea) Erythrocytes Clot  Transport processed molecules. (Blood Cells) (e.g. vitamin D, lactic acid) EDTA Tube  Transport regulatory molecules. (Anticoagulated) Plain Tube 21 (e.g. hormones, enzymes) Homeostasis Protection  Regulate blood pH. (through buffers)  Protect against microorganisms. (e.g. bacterium, virus, fungus, toxin)  Regulate body temperature.  Protect against diseases. (through blood flow, skin) (e.g. cancer, infections)  Regulate blood osmotic pressure or  Prevent excessive blood loss. blood pH. (through dissolved ions, proteins) (maintain haemostasis) (e.g. clot formation)  Regulate blood pressure. 4  Erythrocytes (Red Blood Cells, RBC) Erythrocyte Structure : Biconcave Shape  Life span =  120 days.  Approximately 7 - 8 m in diameter (normocytes). Smaller (microcytes), bigger (macrocytes). Discocyte Areas of central pallor  Shaped like a biconcave disc (discocyte).  No nucleus and other organelles (mitochondria) → Cannot reproduce, have no active metabolism.  Strong and flexible plasma membrane.  Contains haemoglobin (Hb) (O2-carrying protein) → red. Normal Hb – normochromic Low Hb – hypochromic, high Hb – hyperchromic 1 RBC contains 250 million Hb molecules → each carries 4 O2 molecules → 1 RBC = 1000 million O2 molecules  Variations in cell size – anisocytosis.  Variations in cell shape – poikilocytosis.  Variations in cell size and shape – anisopoikilocytosis. 25 26 Normocyte, Microcyte, Macrocyte Variation in RBC Size ( Anisocytosis ) Normocyte (normal size : 7-8 µm) Microcyte Macroyte (smaller size) (bigger size) Areas of central pallor 27 28 Poikilocytosis Anisopoikilocytosis Hypochromic RBC Hyperchromic RBC 29 30 5  Functions of Erythrocyte Leucocytes (Leukocytes)  Transport O2 from the lung to cells.  Transport CO2 from cells to the lung. (white blood cells, WBC) Special characteristics of erythrocyte: Classification by physiological role  Contains haemoglobin (O2-carrying protein).  Phagocytic – granulocytes, monocytes  Shaped like a biconcave disk.  Immunity – lymphocytes  Strong and flexible plasma membrane.  No nucleus and other organelles (mitochondria). Classification by morphology  No active metabolism, cannot reproduce.  Nuclear – erythrocytes, leucocytes, platelets Normal Range :  4.5 - 6.5 x 1012 / L  Granules – granulocytes, agranulocytes.  4.0 - 5.6 x 1012 / L 31 32 Leucocytes (Leukocytes) Classification of Lymphocytes - 5 different subtypes Granular leucocytes By Morphology (shape, structure) Neutrophil – most numerous Small lymphocyte Eosinophil Large lymphocyte Basophil – rarest By Immunological Functions Agranular leucocytes B-lymphocyte (humoral immunity) Monocyte – largest T- lymphocyte (cell-mediated immunity) Lymphocyte – smallest Natural killer cell (NK cell) (cytotoxicity) 33 34 B- versus T-Lymphocytes Parameter B-Lymphocytes T-Lymphocytes Functions of Leucocytes % in peripheral blood 10-20% 60-70% Neutrophils - Combat infections (phagocytosis). Maturation site Phase 1: Bone marrow Thymus - First line of host defence against extracellular bacteria. Phase 2: Lymph nodes, spleen Eosinophils Location in lymph Follicles Paracortex - Reduce allergic reaction & inflammation (histaminase). nodes - Combat parasitic / worm infections (phagocytosis). Function Humoral immunity Cell-mediated - Dissolve blood clots (plasminogen). immunity Antigen receptor Surface T-cell receptor immunoglobulin (Ig) Normal Range :  4 - 12 x 109 / L Cluster Designation CD19, CD20, CD22, CD2, CD3, CD4, CD5,  4 - 12 x 109 / L (CD) CD79a, IgM CD7, CD8 35 36 6 Basophils - Intensify inflammation (histamine, serotonin). Platelets - Promote Type I hypersensitivity / allergy (histamine, SRS-A).  Cytoplasmic fragments (2-3 m diameter). - Prevent blood clotting (heparin).  Life span = 7 - 8 days. - Form mast cells in tissues.  No nucleus, many granules (red-purple). Lymphocytes  Incapable of cell division. - Host defence against viral infections and intracellular bacteria.  Have a complex metabolism. - Cell-mediated immunity (T-lymphocytes).  Functions: - Humoral-mediated immunity (B-lymphocytes).  Prevent excessive blood loss (primary haemostasis) Monocytes by forming platelet plugs. - Combat infections and destroy dead cells (phagocytosis).  Release chemicals that promote blood clotting. - Present antigens to T-lymphocytes. - Form macrophages in tissues :  liver Kupffer cell Normal Range :  150 - 400 x 109 / L  lung alveolar macrophage (Platelets)  150 - 400 x 109 / L  spleen splenic macrophage 37 38 Stem Cells  Reside in the bone marrow.  Very rare cells in circulating blood. need special equipment to capture them.  Express surface protein (CD34).  Have 2 unique biological characteristics : - Self-renewal. - Multi-lineage differentiation.  Functions:  Produce all types of blood cells.  Stem cell transplantation.  Regenerative medicine. 39 40 42 7