Chapter 4 Blood and Hemopoiesis Chapter 4 Blood and Hemopoiesis Li Jinxin, associate professor Department of Histology and Embryology clinical medicine

Objectives Composition of blood. Structure and function of the formed elements of blood. Haemopoietic stem cells and haemopoiesis.

1. Blood 1.1 Composition of blood Blood consist of blood cells and the blood plasma. The cell element include erythrocytes, leukocytes and platelets.

Formed elements: 45% red blood cell (erythrocyte) white blood cell (leukocyte) platelets Plasma: 55%, PH , 90% water plasma protein: albumin, globulin, fibrinogen. lipidprotein, enzymes, hormone, vitamin, inorganic salt and products of metabolism.

Serum: is plasma in which the fibrinogen has been removed by clotting.

1.2 Erythrocyte ( red blood cell) normal number: ( )×10 12 /L in male ( )×10 12 /L in female structure: biconcave discs in shape, um in diameter. no nucleus and organelles filled with hemoglobin, Hb life span: 120 days.

Blood(Wright stain)

hemoglobin,Hb Normal number: g/L in male g/L in female Function: combine and transfer O 2 and CO 2

erythrocyte membrane skeleton: change shape main component is spectrin and actin blood type antigen: A and (or) B membrane protein ABO blood type hemolysis:erythrocyte ghost anemia: RBC <3.0×10 12 /L or Hb <100g/L

reticulocyte reticulocyte 0.5-1% of total erythrocyte population. immature cell remained ribosome delicate network structure when stained with brilliant cresyl blue. will disappear after 1-3 days.

1.3 leukocyte ( white blood cell) a group of large cells with nucleus involve in defense and immune reaction normal number: (4.0-10) ×10 9 /L classification: granulocytes: /neutrophil （ 50%-70% ） /eosinophil （ 0.5%-3% ） /basophil ( 0%-1% ） agranulocytes: /lympocyte （ 25%-30% ) /monocyte （ 3%-8% ）

1.3.1 Neutrophilic granulocyte (neutrophil) LM structure: round, 10-12µm in diameter. polymorphous nucleus, consisting 0f 2-5 sausage- shaped lobes,interlinked by a fine thread of chromatin. Abundant,fine neutrophilic granules,pink cytoplasm.

EM structure: specific granule: 80% small, µm ovoid or irregular in shape contain: lysozyme, phagocytin (defensin) azurophilic granule: 20% large, round or ovoid, µ m electron dense lysosome: acid phosphatase, peroxidase, acidic hydrolase.

Function: phagocytose bacterium. Life span: in blood 6-8 hours, in CT 2-3 days.

1.3.2 Eosinophilic ranulocyte (eosinophil) LM structure: round,10-15µm in diameter. 2 lobes nucleus Abundant, rough, bright red, acidophilic granules.

granules: round or ovoid with cube-liked electron dense crystal contain: lysozyme ACPase histaminase peroxidase EM structure:

Function: counteract the infection of parasite reduce allergic reaction Life span: in blood 6-8 hour, in CT 8-12 days

1.3.3 B asophilic granulocyte (basophil) LM structure: round,10-12µm lobe, “S” shaped or irregular nucleus less, large, dark blue basophilic granules.

Granule contain: Heparin Histamine Acidophil chemotactic factor Cytoplasm contain: leukotriene Function: involve in allergic reaction. Life span: days. EM structure

1.3.4 Lymphocyte LM structure: round, small LC 6-8 µ m, medium-sized LC 9-12 µ m, large LC µ m in diameter. round nucleus with indentation, chromatin appears as spot-liked and electron-dense. cytoplasm: less, basophilic.

EM structure: Azurophilic granule are present.The cytoplasm is lacking in organelles but contains many free ribosomes.

Classification: T cell: thymus dependent lymphocyte, 75%, involve in cellular immune reaction. B cell: bone marrow dependent lymphocyte, 10-15%, become into plasma cell, involve in humoral immune response nature killer cell: 10% Function: involve in immune response

1.3.5 Monocyte LM structure: large round, µm. nucleus appear as kidney, horse-shoe or ovoid in shape. cytoplasm: gray- blue in color, contain azurophilic.

EM structure : Azurophilic granule Function: actively mobile and chemotaxis, phagocytose. Life span: in blood 1-5 days, in CT which become into macrophage.

1.4 Blood platelet cytoplasmic fragment of megakaryocyte in bone marrow normal number: X10 9 /L LM structure: disc-liked, 2-4µm, irregular in shape. in groups. Granulomere and hyalomere

EM structure : tubular systems: opening tubule system: increasing the exchange area, facilitate the intaking and releasing. dense tubule system: SER, collecting Ca 2+ and synthesizing prostaglandin.

granules: specific granule: contains clotting factor, fibrinogen, acidic hydrolase dense granule: contains 5-hydroxytryptamine, ADP,ATP, Ca 2+ and adrenalin.

Function: involve in clotting and stopping the bleed. protecting endothelium and take part in repairing of endothelium.

2. Bone marrow and hemopoiesis 2.1 Places for hemopoiesis yalk sac ( 3W) liver (6W) spleen (4M) bone marrow

2.2 Structure of bone marrow red bone marrow:hemopoietic tissue reticular tissue,hemopoietic cell, macrophage, fibroblast, lipid cell and mesenchymal cell and sinus.

Hemopoietic inductive microenvironment ( HIM): The environment for hemopoietic cell growth and development. stromal cells: including reticular cell, fibroblast, macrophage, endothelial cell and lipid cell.

2.3 Hemopoietic stem cell and hemopoietic progenitor cell hemopoietic stem cell(HSC): multipotential stem cell originated yalk sac, constitutes about 0.5% of total bone marrow cells.similar to small LC. feature: strong potential to proliferation. multidifferentiated ability. ability to copy itself.

2.3.2hemopoietic progenitor cell(HPC): committed stem cell Erythrocytes HPC Granulocytes and monocytes HPC Megakaryocytes HPC

2.3.3 General regulation of hemopoietic processes: main steps: promordial stage immature stage mature stage

2.3.4 Regulations: size of cell become smaller and smaller Nucleus become smaller and smaller or disappears. Chromatin: from fine and loose to rough and dense. cytoplasm: more and more basophilic: weaker and weaker specific granule: more and more ability to division: from have to no, but keep the potentials.

Questions 1.Describe the composition of blood and state the normal value of each formed element in adult humans. 2.What is the classification of leukocytes according to? 3.What are the structural features of various blood cells?