Zhikal O. Khudhur/Assist lecturer_____________________________________________Hematology– 3rd Stage /1st Semester

zhikal.omer@tiu.edu.iq 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.

•

•

•

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.

•

• Supplies stem and spleen.Stores iron

cells for lymphocyte production in thymus

•

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

•

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

•

•Thymus

Parenchyma consists of diffuse lymphoid tissues containing T-(thymus)

Secondary lymphoid organs

•

•(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•

•

•

Produces lymphocytes and plasma

Synthesizes antibodies.

Reservoir of erythrocytes andthrombocytes

cells

• Destroys senescent anderythrocytes

Degrades hemoglobin

Stores iron

abnormal

•

•

Why act as Graveyard for RBC?

Liver•

•

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

•

•

•

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……..

•

SHAPE AND STRUCTURE OF ERYTHROCYTES

erythrocytes production degradation

HEMOGLOBIN• Heme and globin synthesis

• Structure , Function and Variation

• Oxygen and Hb Dossociationcurve

•

•

•