This document discusses hematopoiesis, the formation of blood cells. It begins by describing the components of blood, including formed elements like red blood cells, white blood cells, and platelets. It then explains the stages of blood cell development, or hematopoiesis, including erythropoiesis, leukopoiesis, granulopoiesis, and thrombopoiesis. The document discusses where hematopoiesis occurs, including the primary organs of bone marrow and thymus and secondary organs like the spleen. It also covers hematopoiesis during prenatal development and in adulthood. In summary, the document provides an overview of the components of blood and the process by which blood cells are formed

1. BLOOD CELLS AND HEMATOPOESIS
presented by
MISS TASMIA ZEB

2. COMPONENT OF THE BLOOD
Blood is specialized
connective tissue
Composed by :
•Formed elements
•Fluid component , Plasma
(the extracellular(matrix)

3. FORMED ELEMENTS OF BLOOD
Formed elements : cells
and cell fragments
(platelets)
The cells of blood :
•red blood cells (RBC)
•white blood cells
(WBCs, leukocytes).

4. Haemopoiesis: Stages in the development of blood cells

5. HEMATOPOIESIS
• Mature blood cells have a relatively short life
span
• Must be continusly replaced by stem cells
• Stem cells produce in HEMATOPOIETIC ORGAN

6. short definitions
Haematopoiesis is the formation of blood cellular components.
• All cellular blood components are derived from haematopoietic stem cells.
Erythropoiesis is the process which produces red blood cells.
• which is the development from erythropoietic stem cell to mature red blood cell.
Leukopoiesis is a form of hematopoiesis in which white blood cells (WBC, or
leukocytes) are formed in bone marrow
• located in bones in adults
• hematopoietic organs in the fetus.
Granulopoiesis is the process by which committed hematopoietic progenitor cells
develop into granulocytes under the influence of various growth factors and
cytokines.
Thrombopoesis
Platelets are produced from very large bone marrow cells called megakaryocytes.
As megakaryocytes develop into giant cells, they undergo a process of
fragmentation that results in the release of over 1,000 platelets per
megakaryocyte.

7. Hematopoietic stem cells
An immature cell that can develop into all types of blood cells,
including white blood cells, red blood cells, and platelets.
Hematopoietic stem cells are found in the peripheral blood and the
bone marrow. Also called blood stem cell.
• Multi-potency is the ability to differentiate into all functional
blood cells.
• Self-renewal is the ability to give rise to Hematopoetic stem cell
itself without differentiation.
Pluripotent cells can give rise to all of the cell types that make up the
body; embryonic stem cells are considered pluripotent.
Multipotent cells can develop into more than one cell type, but are
more limited than pluripotent cells; adult stem cells and cord blood
stem cells are considered multipotent.

8. HEMATOPOIESIS
ERYTHROPOESIS: Formation of the
erythrocytes (RBCs red blood cells)
LEUKOPOESIS: Formation of the white blood
cells
GRANULOPOESIS:Formation of the
granulocytes (neuthrophil, eosinophil, and
basophil
THROMBOPOESIS: Formation of the platelets

9. Hematopoesis loation
Hematopoesis occour in primary and secondary
organs:
primary organs include:Bone marrow and
thymus
secondary organs include:spleen,lymphatic
system and tonsils
THYMUS: Glandular lymphatic organ near the
heart where T lymphocytes mature well
developed at birth and increase in size until
puberty when it starts to decrease in size.

10. PRENATAL HEMOPOIESIS
• Subdivide into four phases :
– Mesoblastic :
• begin after 2 weeks after conception at yolk sac
• Mesenchymal cells aggregate into blood islands
– Hepatic
• Begins at 6 weeks until end of gestation
• Nucleated erythrocyte
• Appear of leucocyte (8th week)
– Splenic
• Begin at second trimester until end of gestation
– Myeloid
• Begin at the end of second trimester
• Hemopoiesis at bone marrow

11. POSTNATAL HEMOPOIESIS
• Hemopoiesis almost exclusively in BONE
MARROW
• Stem cells undergo
– multiple cells divisions
– and differentiation
• Replace the cells that leave the blood stream,
die or destroy

12. Haematopoiesis during foetal life and infancy
Blood cell production begins at 14–20 days in the foetal sac and this is the site
of haematopoiesis for about 2 months. The liver and spleen become the main
sites of blood cell production during the second trimester of pregnancy and
foetal bone marrow in the third trimester. At birth, haematopoiesis is
confined to the bone marrow. During infancy and up to about 4 years of age,
almost all the bones of the body contain blood cell producing red marrow.
Haematopoiesis during adult life
By about 25 years of age, the main sites of haematopoiesis are the vertebrae,
ribs, sternum, skull bones, pelvis and sacrum, and the proximal ends of the
femur and humerus. At these sites about half the marrow is red active cell
producing marrow and the remainder, non-cell producing yellow fatty
marrow. Other bone marrow cavities in the body contain nonhaematopoietic
fatty marrow. In certain blood disorders, e.g. chronic dyserythropoietic and
haemolytic anaemias and myelofibrosis, blood cell production can resume in
the liver and spleen (extramedullary haematopoiesis) and the fatty marrow in
some bones can become replaced by haematopoietic marrow.

13. HEMOPOIETIC GROWTH FACTORS
Table 10-6 Gartner colour text histology
• Regulated the hemopoiesis
• Produce by spesific cells
• Acts on spesific stem cells, progenitor cells, and
precursor cells
• The route to deliver growth factor :
– Via blood stream
– Secrete near the hemopoietic cells
– Direct cell-cell contact
• Induced rapid mitosis or and differentiation
• Most ot them are glycoproteins

15. ERYTHROCYTE Biconcave-shape disk
Without nuclei and
organelles
Have soluble enzymes
Filled with Hemoglobin
(Hb)
Average life span of
erythrocyte : 120 days

16. GRANULOCYTOPOIESIS

17. NEUTROPHILS •60-70% of total
leucocytes
•9-12 µm in diameter
•Multilobe nucleus
•Female : drum stick/Barr
Body
• Granules :
•Small spesific granules
•Azurophilic granules (Lysosomes)
•Tertiary granules (gelatine and cathepsins)
•Function :
•Phagocytes

18. EOSINOPHILS
4% of total leucocyte
10 - 14 µm in diameter
Bilobed nucleus
Many large spesific
granules stained by eosin
Function :
•Eliminate antibody-
antigen complexes
•Destroy parasitic
worms

19. BASOPHILS <1% of total leucocyte
8-10 µm in diameter
S-shape nucleus (irregular lobes)
Large spesific granules obscured
the nucleus
Granules (dark blue) contain
heparin & histamin
Surface receptor (Ig E receptors)
Function :
As initiator of inflamatory
process

20. BONE MARROW
A gelatinous, vascular connective
tissue located in medulary cavity
of long bones
Responsible for hemopoiesis
Structure :
Vascular compartment
Extensive network of
sinusoids , arteries and
veins form the
Hemopoietic compartment
Islands of hematopoietic
cells
Hemopoietic cells in
various stage of
maturation

21. LYMPHOCYTES
20%-25% of total leucocyte
8-10 µm in diameter
Round nucleus with slight
indented, occupies most of
the cell
Contain few azurophilic
granules

22. MONOCYTES
Largest circulating blood
cells
3-8% ot total leucocyte
Large, acentric, kidney-
shape nucleus
numerous azurophlic
granules
Migrate to the
connective tissue 
MACROPHAGES
(phagocytose antigens
and as APC)

23. RED VS YELLOW BONE MARROW

24. PLATELET FORMATION
• CFU-Meg, gives rise the Megakaryoblast
• Megakaryoblast differentiate 
Megakaryocytes (single lobulated nucleus)
• Megakaryocytes protrude  clusters of
proplatelets  platelets

25. PLATELETS
250.000-400.000
platelets/mm3
2 to 4 µm in diameter
Display peripheral clear
region (hyalomere ) and
central darker region
(granulomere)
receptor molecules
(glycocalyx) on
plasmalemma
Function : Blood clott

26. LEARNING TASKS
• Expain the composition of the blood!
• Explain the structure of formed elements of blood!
• How to differentiate the blood cells from a blood-smear?
• Explain the classification and function of leucocyte !
• Explain the maturation of lymphocyte!
• What blood cell would be in abundance during an active
parasitic infection? Explain your answer!
• Eplain the structure and function of platelets!
• What blood cell in bone marrow is the earliest recognizable
stage of the red blood cell line?
• Describe the structure of erythrocyte if lack of this nutrient:
vitamin B12 and iron during the erythrocytopoiesis