Download - Lec. 2: Hematology
Zhikal O. Khudhur/Assist lecturer_____________________________________________Hematology– 3rd Stage /1st Semester
[email protected] https://tiu.edu.iq/
2021 - 2022
TIU - Faculty of ScienceMedical Analysis Department
Lec. 2: Hematology
Prenatal and neonatal hemopoiesis• Progressive hemopoiesis in these organs results from
in situ differentiation of circulating stem cells.
• The liver and spleen are inactive but retain potentialto revert to hemopoiesis in diseases of bone marrow
Prenatal and neonatal hemopoiesis
Hemopoietic cells in human embryo first appears in yolksac wall.
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Later Thymus, liver and spleen are seeded.Towards term and postnatally bone marrow becomemajor site of hemopoiesis.
• Figure 1: Sequence and contribution ofcellhemopoietic organs
formation in catsto prenatal blood
%100
90
80
70
60
50
40
30
20
10
0
0 5 15 20 25 30 35 40 45 50 55 60 65 70 75
Days
Yolk sac Liver Bone marrow
er
Sites of Hemopoiesis• Yolk sac :Begins in
mesoderm of yolk sacforming erythroid cellssite where blood cells andblood vessels are firstformed. Productioncontinues until 2.5 fetalmonths
Liver and spleen Fetal liv•assumes responsibility forhematopoiesis duringsecond month
Bone marrow•
The bone marrow is actually one of the largest organs inthe body, approaching the size and weight of the liver. Itis also one of the most active.
Produces erythrocytes, granulocytes, monocytes, platelets and B-lymphocytes.
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• Supplies stem and spleen.Stores iron
cells for lymphocyte production in thymus
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Q/ how many boneshave bone marrow?
5% of total body massaround 3.65 kg
• • Appendicular skeleton:Active Hemopoieticmarrow is found, inchildren throughout
Axial skeleton:
Bones of the Upper &Lower limbsthe:
• • In Adults activehemopoietic marrow isfound only in:
The axial skeleton and The proximal ends of the appendicular skeleton.
(Cranium , Ribs.,VertebraeSternum
Pelvis), and
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Cellularity (%)
100 t--h - +--+---+---+--+---+---+---+-
+::
Bone marrow
Yolk sac
'"J.,_..j..-+--ttr-i Lymph nodes� " r l
i , - , t - . - - + - - �
OHepatic
1 2 3 4 5 6 7 8 9 10 20 30 40 5060
Fetal months Birth Age inyearsSites of hematopoiesis
I Mesoblastic
8 Myeloid
Lymph nodes• Produce lymphocytes and plasma
cells
Produce antibodies.
primary lymphoid organs
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•Thymus
Parenchyma consists of diffuse lymphoid tissues containing T-(thymus)
Secondary lymphoid organs
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•(spleen, lymph nodes, hemal nodeshemal lymph nodes, tonsils,Peyer’s patches and gut associatedlymphoid tissues contain nodularand diffuse lymphoid tissues.
Thymus
• Central lymphoid organ where bone marrow derivedprecursor cells differentiate into immunologicallycompetent T-lymphocytes
Spleen•
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Produces lymphocytes and plasma
Synthesizes antibodies.
Reservoir of erythrocytes andthrombocytes
cells
• Destroys senescent anderythrocytes
Degrades hemoglobin
Stores iron
abnormal
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Why act as Graveyard for RBC?
Liver•
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Stores vitamin B12, foliate and iron
Produces coagulation factors,albumin, and some globulins.
Converts free bilirubin to bilirubin glucuronide for excretion into bile
Participates in entero-hepatic circulation of urobilinogen
Produces α-globulin, a precursor oferythropoietin
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Kidneys• Produce erythropoietin and thrombopoietin
• Degrade excessive hemoglobin to bilirubin for urinaryexcretion
Stomach and intestines• Produce HCl for release of iron from complex organic
molecules.
Produce intrinsic factor to facilitate absorption of vitamin•B12.
Absorb vitamin B12 and folic acid through intestinal•epithelial cells.
Control the rate of iron absorption in relation to body needs•
Lifespan and production of blood cells
rate Kg/yearCell type Approximate
lifespanProduction
rate cells/dayProduction
rate cells/sec
Production
Red Cells 100 days 2 x 1011 2.3 million 7.3
Neutrophils t½ 6 hours 3 x 1010 350,000 10.9
Platelets 7 days 1 x 1011 1.2 million 4.6
Lymphocytes t½ 10 days 1 x 1010 116,000 3.7
Annual total 26.5 Kg
Nex t Lecture……..
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SHAPE AND STRUCTURE OF ERYTHROCYTES
erythrocytes production degradation
HEMOGLOBIN• Heme and globin synthesis
• Structure , Function and Variation
• Oxygen and Hb Dossociationcurve
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