Blood tissue. 5. Bone marrow 6. Stages and sites of hemopoiesis 7. Hematopoiesis: erythropoiesis granulopoiesis megakaryocytopoiesis

Transcription

1 Blood tissue 1. Blood as a tissue 2. Functions and composition of blood 3. Plasma. Antibodies 4. Formed elements of blood: erythrocytes leukocytes platelets 5. Bone marrow 6. Stages and sites of hemopoiesis 7. Hematopoiesis: erythropoiesis granulopoiesis megakaryocytopoiesis 8. Regulation of hematopoiesis

2 Blood as a tissue Blood tissue A. Hadjiolov, 1930 specialized (trophic-defensive) fluid form of connective tissue liquid intercellular substance: plasma formed elements of blood (blood cells): erythrocytes (red blood cells) 96% leukocytes (white blood cells) 3% thrombocytes (blood platelets) 1% Prof. Dr. Nikolai Lazarov 2

3 Functions of the blood transport nutrients, gases (О 2, СО 2 ), hormones, waste products of metabolism removes toxins from the body maintains body temperature buffer рн control, homeostasis defense leukocytes, antibodies blood clotting prevention of hemorrhage Prof. Dr. Nikolai Lazarov 3

4 Composition of blood amount: 4-6 liters in a man, ~7-8% of its body weight arteries 1 liter veins 3 liters heart blood depots plasma: 55% blood cells: 45% hematocrit: in men in women Prof. Dr. Nikolai Lazarov 4

5 ~55% of whole blood Composition: 92% water, 7-8% proteins, 1-2% electrolytes, nutrients (glucose, amino acids, fatty acids), vitamins, gases, metabolites osmotic pressure: 0.85% NaCl ph: serum = plasma fibrinogen plasma proteins: albumins (Lat. albus, white): 60% maintaining the osmotic pressure globulins: α, β, γ (immunoglobulins) 20% fibrinogen: blood clotting lipoproteins HDL, LDL complement proteins Blood plasma Gr. plasma, something molded or created Prof. Dr. Nikolai Lazarov 5

6 Formed elements of blood Giemsa-stained blood smear acid and basic dyes: Prof. Dr. Nikolai Lazarov methylene blue, eosin, azure, methyl violet 6

7 Jan Swammerdam ( ) Red Blood Cells (RBCs) Gr. erythros, red total number: 25х10 12 /blood ~ 4-6 million/mm x /l x /l erythrocytosis (polycythemia) anemia size: 7.5±0.5 µm > 9 µm: macrocytes > 12 µm: megalocytes < 6 µm: microcytes anisocytosis, Gr. aniso, uneven diameter: 0.8 µm in the center 2.6 µm at the rim shape: flexible biconcave disks spectrin total surface: 140 µm 2 (3500 m 2 ) Erythrocytes 1658 Jan Swammerdam Prof. Dr. Nikolai Lazarov 1674 Anton van Leeuwenhoek 7

8 Erythrocytes lack a cell nucleus and most organelles hemoglobin > 90% of dry content: g/l heme+globin hemoglobin types: HbА 1 (2α+2β): 96-97% HbA 2 (2α+2δ): 2% HbF (2α+2γ): 1-2% in adults, 80% in newborns increased level in thalassemia HbS sickle cell disease Prof. Dr. Nikolai Lazarov 8

9 Plastic plasmalemma [40% lipids (incl. phospholipids, glycolipids, cholesterol), Erythrocytes 50% proteins, 10% carbohydrates]: glycophorins A, B, C transmembrane, single-pass glycoproteins that carry the MNS blood groups antigens protein Rh-antigen Main function: transport of oxygen O 2 oxyhemoglobin CO carboxyhemoglobin CO 2 carbaminohemoglobin Lifespan in the bloodstream: 120 days ~140 days; ~109 days Prof. Dr. Nikolai Lazarov 9

10 Reticulocytes Lat. rete, network young erythrocytes = polychromatophilic erythrocytes ( % of the total number of RBCs) morphological characteristics: reticular (mesh-like) network of rrna (polyribosomes) substantia reticularis basophilic nuclear fragments of DNA Howell-Jolly bodies mitotic spindle (microtubule) remnants Cabot rings pathological conditions: reticulocytosis elevation in the number of reticulocytes (after acute haemorrhage, ascent to high altitude, chronic haemolytic anaemia) loss of reticulocytes in the peripheral blood: unsufficient erythropoiesis Prof. Dr. Nikolai Lazarov 10

11 Leukocytes White Blood Cells (WBCs) Gr. λευκό, leukos, white total number: 4-10x10 9 /l blood leukocytosis leukopenia (Gr. λευκό, white + πενία, deficiency) two groups and five types leukocytes: granulocytes (polymorphonuclear leukocytes) neutrophilic granulocytes eosinophilic granulocytes basophilic granulocytes agranulocytes (mononuclear leukocytes) lymphocytes monocytes Prof. Dr. Nikolai Lazarov 11

12 Percentage of leukocytes differential count (frequency) of blood leukocytes: granular leukocytes (granulocytes): (Lat. granulum, granule + Gr. kytos) neutrophils 60-70% eosinophils 2-4% basophils 0.5-1% band cells 2-3% (immature neutrophils) agranular leukocytes (agranulocytes): lymphocytes 20-30% monocytes 3-8% Prof. Dr. Nikolai Lazarov 12

13 Neutrophils: 60-70% of all leukocytes size (in diameter): µm segmented nucleus 2-5 (usually 3) lobes > 5 lobes hypersegmented Polymorphonuclear leukocytes Granules: total number specific (В-granules): 80% small-sized µm lysozyme, lactoferrin, collagenase, several nonenzymatic antibacterial basic proteins, alkaline phosphatase azurophilic (А-granules): 15% lysosomes µm acid hydrolases, peroxidase etc. Prof. Dr. Nikolai Lazarov 13

14 Functions of neutrophils Life span: h in the bloodstream, 1-4 days in the connective tissue diapedesis through the blood vessel walls phagocytosis (microphages): specific granules + membrane of the phagosome bactericide substances azurophilic granules fusion with the phagosome lysis of target cell exudative phase of inflammation pus (dead neutrophils, bacteria and semi-digested material) Prof. Dr. Nikolai Lazarov 14

15 Eosinophils: 2-4% of leukocytes size (in diameter): µm Eosinophilic granulocytes bilobed nucleus specific granules: about 200/cell, µm/0.3-1 µm LM: acidophilic (eosinophilic) acid phosphatase, arylsulfatase, peroxidase, histaminase, protein cations (MBP, ECP, EPO, EDN) ЕМ: ultrastructure unit membrane, crystalline core (major basic protein), parallel to the long axis of the granule azurophilic granules: lysosomal enzymes Prof. Dr. Nikolai Lazarov 15

16 Functions of eosinophils Life span: 6-16 h in the blood 8-12 days in the connective tissue motile cells: chemotaxis (ECF-A) mast cells expression of receptors for IgE: destruction of parasites (helminthic infections) allergic processes anaphylaxis inactivation of leukotrienes (SRS-A) and histamine produced by other cells Prof. Dr. Nikolai Lazarov 16

17 Basophilic granulocytes Basophils: less than 1% of leukocytes size (in diameter): µm large nucleus irregular lobes U- or S-shaped specific granules: 0.5 µm metachromasia similar to mast cells histamine, (serotonin), heparin, prostaglandins ultrastructure dense-cored granules azurophilic granules: lysosomes hydrolytic enzymes Prof. Dr. Nikolai Lazarov 17

18 Functions of basophils Life span: 10-12h in the blodstream motile cells: chemotaxis expression of receptors for IgE: allergic processes cutaneous basophil hypersensitivity Prof. Dr. Nikolai Lazarov 18

19 Lymphocytes: size (in diameter): small 6-8 µm medium 8-12 µm large µm nucleus: large, hyperchromatic, eccentrically located cytoplasm: scanty, thin rim around the nucleus basophilic with many free polyribosomes B-lymphocytes Т-lymphocytes NK cells (NKC) Agranulocytes Prof. Dr. Nikolai Lazarov 19

20 Functions of lymphocytes humoral immune response B-lymphocyte plasma cells antibodies cell-mediated immune response Т-lymphocyte lymphokines cell-bound antibodies T H 1 T H 2 T S T K (NKC) T A T M Prof. Dr. Nikolai Lazarov 20

21 Agranulocytes Monocytes: size (in diameter): µm nucleus: eccentrically placed, oval, horseshoe- or kidney-shaped with 1-2 nucleoli pinocytotic vesicles and many microvilli cytoplasm basophilic (bluish-gray color) Granules: very fine azurophilic (lysosomes) peroxidase-positive (acid phosphatase) peroxidase-negative (nonspecific esterase) Prof. Dr. Nikolai Lazarov 21

22 Functions of monocytes Life span: 1-8 h in the bloodstream do not complete their differentiation no functions in the blood vessels after crossing capillary wall they enter connective tissue: months-to-years life phagocytosis macrophages antigen-presenting cells play an essential role in recognition and interaction of antigen and immunocompetent cells Prof. Dr. Nikolai Lazarov 22

23 Prof. Dr. Nikolai Lazarov 23

24 Platelets fragmentations from giant polyploid megakaryocytes: number: 20-40х10 9 /l ellipsoid or discoid in shape size: µm central zone granulomere (chromomere) containing purple granules peripheral light-blue-stained transparent zone hyalomere (microtubules and actin filaments) Prof. Dr. Nikolai Lazarov 24

25 Ultrastructure of platelets membrane with prominent glycocalyx: cell adhesion molecules platelet adhesion to the capillary wall cytoplasm: open canalicular system (channels) actin-containing microfilaments granules: alpha granules ( µm) platelet-derived growth factor (PDGF), platelet factor IV, other clotting proteins (thrombospondin and fibronectin, and von Willebrand factor) delta (beta) granules ( µm) dense bodies Ca 2+, pyrophosphate, ADP, ATP, serotonin, histamine lambda granules ( µm) lysosomes hydrolytic enzymes peroxisomes peroxidase and probably catalase activity Prof. Dr. Nikolai Lazarov 25

26 Life span: 9-12 days in blood Functions hemorrhage control: hemostatic mechanism: platelet adhesion platelet aggregation platelet plug blood coagulation fibrin formation blood clot (thrombus) clot retraction clot removal plasmin Platelet functions Prof. Dr. Nikolai Lazarov 26

27 Hematopoiesis Hemopoiesis, Gr. haima, blood + poiesis, a making (origin and maturation of new blood cells) еrythropoiesis = formation of erythrocytes granulopoiesis = formation of granulocytes mono-/lymphocytopoiesis = formation of agranulocytes megakaryocytopoiesis = formation of platelets Hemopoietic tissues blood-forming tissue, consisting of reticular fibers and similarly specialized connective tissue cells of mesenchymal origin that give rise to new blood cells myeloid tissue, Gr. µυєλός, myelos, marrow (red bone marrow) = formation of most of the blood cells: erythrocytes, granulocytes and thrombocytes (platelets) lymphoid tissue (thymus, spleen) = formation of T-lymphocytes, proliferation of B-lymphocytes, immune defense (lymph nodes and associated lymphoid tissue, MALT, GALT, BALT) Prof. Dr. Nikolai Lazarov 27

28 Periods of hematopoiesis prenatal hematopoiesis (intraembryonic): mesoblastic (megaloblastic) phase 14 days (2 nd gestational week) yolk sac mesoderm hemocytoblasts hepatolienal phase 5 th to 6 th gestational week liver erythrocytes spleen Er+granulocytes, lymphocytes (after 5 th month) thymus Т-lymphocytes medullary (myeloid) phase since 4 th month bone marrow liver and spleen postnatal hematopoiesis: myeloid phase in red bone marrow (textus myeloides) red (hematogenous) yellow bone marrow Prof. Dr. Nikolai Lazarov 28

29 Mesoblastic phase Megaerythroblastic hematopoiesis: erythrocytopoiesis, incl. normoblast absent granulo, mono- and lymphocytopoiesis initial blood cell hemocytoblast = pluripotential stem cell: large, spherical, basophilic synthesize hemoglobin form primitive erythrocytes (located in groups or islets blood islands, retain their nuclei) Prof. Dr. Nikolai Lazarov 29

30 NB! Hepatolienal phase NB! from 2 nd -3 rd month until birth hematopoietic organs: liver spleen thymus normal precursor cells and erythrocytes, no megakaryoblasts erythroblasts (from lymphoid organs) begin of leukopoiesis lymphocyte appearance Prof. Dr. Nikolai Lazarov 30

31 Medullary phase begin in clavicle 2 nd month in the 5 th fetal month the major blood-forming organ is the red bone marrow all cell lines of hematopoiesis lymphoid organs only lymphoblasts Prof. Dr. Nikolai Lazarov 31

32 Unitary (monophyletic) theory Alexander А. Maximow, 1901 Common undifferentiated stem cell (hemocytoblast): one of 1000 nuclear cells in the bone marrow origin: mesenchyme of the embryonic sac (3 rd week) functionally distinct but morphologically indistinct has the potential to give rise to any type of blood cells Pluripotent stem cell Progenitor cell (CFU, CFC) (uni- and bipotent) Precursor (blast) cell functional blood cell Prof. Dr. Nikolai Lazarov 32

33 (colony-forming units) Stem cells CFU erythrocyte (CFU-E) CFU granulo-monocyte (CFU-GM) CFU lymphocyte (CFU-L) CFU megakaryocyte (CFU-Me) Two types of pluripotent stem cells: type І 10% in permanent mitosis type ІІ 90% in G 0 phase Prof. Dr. Nikolai Lazarov 33

34 Erythrocytopoiesis Basic principles in maturation of red blood cells: decrease in cell size and volume loss of nuclear material and disappearing of cellular organelles: - increase of condensed chromatin - decrease in the number of nucleoli - basophilia is replaced by acidophilia synthesis and accumulation of hemoglobin = decrease in the processes of dividing = loss in the proliferative capabilities = decrease in the synthetic processes Prof. Dr. Nikolai Lazarov 34

35 Erythrocytopoiesis duration approximately 7 days the division stops at normoblast level stimulated by erythropoietin, folic acid, iron, vitamin B 12 Cell Size Nucleus Cytoplasm Proerythroblast µm large, prominent nucleolus Basophilic еrythroblast µm condensed, no visible nucleolus basophilic basophilic Polychromatophilic еrythroblast Orthochromatophilic erythroblast (Normoblast) Polychromatophilic erythrocyte (Reticulocyte) µm reduced under 50% basophilic to acidophilic 8-10 µm small, condensed no basophilia is evident 8-10 µm no nucleus acidophilic Prof. Dr. Nikolai Lazarov 35

36 diferentiation and maturation about days Basic principles in granulocyte formation: moderate decrease in the cell volume increase in the nuclear density and segmentation accumulation of specific granules Granulocytopoiesis Prof. Dr. Nikolai Lazarov 36

37 Granulocytopoiesis the myelocyte is the last cell to divide Cell Size Nucleus Cytoplasm Myeloblast µm large with finely dispersed chromatin Promyelocyte µm oval with condensed chromatin light blue, without visible granules basophilic with azurophilic granules (blue) Myelocyte µm small oval specific granules (pink) Metamyelocyte µm kidney-shaped filled with granules Prof. Dr. Nikolai Lazarov 37

38 Lymphocytopoiesis in lymphoid tissue: thymus lymph nodes spleen maturation principles: condensation of chromatin decrease in cellular volume dedifferentiation ability no evident morphological changes in differentiation: pluripotent stem cell unipotent progenitor cell В- and Т-cell stem cell lymphoblast (15-20 µm) prolymphocytes В- and Т-lymphocytes Lymphoblast Prolymphocytes Prof. Dr. Nikolai Lazarov 38

39 Monocytopoiesis maturation (55 h): decrease in cell size appearance of small number of fine azurophilic granules monocytes arise from a pluripotent stem cell in the bone marrow: multipotent progenitor cell bipotent progenitor cell (commited for neutrophils and monocytes) monoblast promonocyte monocyte Prof. Dr. Nikolai Lazarov 39

40 Thrombocytopoiesis megakaryocyte (Gr. megas, big, + karyon, nucleus, + kytos, cell), giant cell ( µm) in the red bone marrow maturation stages: megakaryoblast promegakaryocyte megakaryocyte platelets Prof. Dr. Nikolai Lazarov 40

41 Thrombocytopoiesis Cell Size Nucleus Cytoplasm megakaryoblast µm large ovoid or kidney-shaped, numerous nucleoli, peripherally dense heterochromatin homogenous and intensely basophilic promegakaryocyte µm large and highly lobulated lightly-stained with centrally located azurophilic granules megakaryocyte µm irregularly lobulated, highly polyploid (4N-64N), coarse chromatin and no visible nucleoli spotted basophilic with azurophilic granules Prof. Dr. Nikolai Lazarov 41

42 Regulation of hematopoiesis hematopoietic growth factors colony-stimulating factors (CSF) hematopoietins (poietins) Prof. Dr. Nikolai Lazarov 42

43 Thank you... Prof. Dr. Nikolai Lazarov 43