HEMATOPOIESIS Flashcards
is a continuous, regulated
process of blood cell production
Hematopoiesis/Hemopoiesis
Hematopoiesis includes:
- Cell Renewal – replenishment
- Proliferation – multiplication
- Differentiation – immature to immature
- Maturation
What are the two hematopoietic development?
- Prenatal/Fatal Development
- Postnatal/Adult Hematopoiesis
What are the examples of Prenatal/Fatal Development
- Mesoblastic
- Hepatic
- Myeloid
Primitive erythrocytes are found in the yolk sac arise from mesodermal cell
mesoblastic phase
chief site of mesoblastic where
hematopoiesis takes place
yolk sac
Begins around the 19th day of embryonic
development after fertilization
mesoblastic phase
Fifth month of fetal development
Medullary (Myeloid) Phase
first fully developed organ in the fetus. The major site of T cell production
Thymus
The hepatic phase of hematopoiesis begins at 5 to 7 gestational weeks
Hepatic phase
needed for oxygen transportation, not found in Adult Life
Embryonic Hemoglobin
Globin Chain Combination for Gower II
2 alpha 2 epsilon
Globin Chain Combination for Gower I
2 epsilon 2 zeta
chief site with the help of Spleen
Liver
Characterized by recognizable clusters of developing
erythroblasts, granulocytes, and monocytes colonizing
the fetal liver, thymus, spleen, placenta
Hepatic phase
The developing erythroblasts signal the beginning of
definitive hematopoiesis with a decline in primitive
hematopoiesis of the yolk sac.
Hepatic phase
Embryonic Hemoglobin is replaced by ______ and detectable ______
Hemoglobin F ; Hemoglobin A
Organs which produce B cells
Kidney, Spleen
Adult Hemoglobin
Hb A, Hb A2
Globin Chain Combination for Hb A
2 alpha 2 beta
Globin Chain Combination for Hb A2
2 alpha 2 delta
Adult hematopoietic tissue located in
→ Bone Marrow
→ Lymph Nodes
→ Spleen, Liver
→ Thymus
Hematopoietic tissue is involved in the proliferation and
maturation of blood cells.
POSTNATAL DEVELOPMENT
Organs involved in postnatal development.
A. Bone marrow – largest
B. Liver
C. Spleen
D. Lymph Nodes
E. Thymus
One of the largest organs in the body
Bone marrow
Major function of bone marrow
proliferation and production of blood cells
Hematopoietically inactive marrow
composed primarily of adipocytes and fat
cells, with undifferentiated mesenchymal
cells and macrophages.
Yellow marrow
Hematopoietically active marrow
consisting of the developing blood cells and their progenitors (flat bones of the skull, clavicle, sternum, ribs, vertebrae and pelvis
Red marrow
Immature,
undifferentiated hematopoietic cells
committed to a definite cell lineage yet to
be identified
progenitors
Production of erythrocytes, platelets, basophil, etc.
Common myeloid progenitors
production of Lymphocytes
Common Lymphoid
Progenitors
4 Main Functions of Red Bone Marrow
- Production of blood cells
- Destruction of erythrocytes
- Iron storage (from Hb breakdown)
- Central organ for B lymphocyte development
2 major components of bone marrow
- red marrow
- yellow marrow
Becomes abundant during 5 and 7 years of age where they occupy the spaces in the long bones previously dominated by red marrow
yellow marrow
Plays an important role in stem cell differentiation
and proliferation.
Hematopoietic Microenvironment
Regulate the flow of particles entering and
leaving hematopoietic spaces.
Endothelial cells
It is responsible for supplying semifluid matrix (stroma) that serves as an anchor for the developing hematopoietic cells.
Hematopoietic Microenvironment
Secrete various steroids that influence
erythropoiesis, maintains e bone integrity
and regulates the volume of marrow.
adipocytes
Function in phagocytosis and secretion of
various cytokines that regulate
hematopoiesis contiunation
macrophages
Are bone-forming cells – water bug or comet
appearance (plasma cell)
osteoblasts
Bone resorbing cells or destroying cells
osteoclast
Supports the vascular sinuses and
developing hematopoietic cells
Reticular Cells (fibroblasts)
Composition of Extracellular Matrix of BM
- Proteoglycans/Glycosaminoglycans
- Fibronectin
- Collagen
- Laminin
- Hemonectin
- Thrombospondin
serves as the major site of blood cell production
during the second trimester of fetal development
Liver
Function of liver
1) Protein synthesis and degradation
2) Coagulation factor synthesis carbohydrate
and lipid metabolism
All coagulation factors are
synthesized in the liver except for
FIV
3) Drug and toxin clearance
4) Iron recycling and storage
5) Hemoglobin degradation
largest lymphoid organ in the body.
spleen
It is vital but not essential for life
spleen
Composed primarily of vascular sinusoids
and sinuses separated.
red pulp
Consists of scattered follicles with
germinal centers containing lymphocytes,
macrophages, and dendritic cells
white pulp
Cells are phagocytized with subsequent
degradation of cell organelles
The whole RBC is taken care off
culling
Splenic macrophages remove inclusions
or damaged surface membrane from the
circulating RBCs
Only the damaged part is removed
Pitting
bean-shaped structures
Lymph Nodes
Size of lymph node
(1-5 mm)
→ Outer Region
→ Contains follicles of B cells
→ Proliferation termed germinal factors
cortex
→ Region between cortex and medulla.
→ Contains predominantly T cells and numerous
macrophage.
paracortex
→ Inner region
→ Consists primarily of T lymphocytes and
plasma cells
medulla
Originates from endodermal and mesenchymal
tissues
thymus
a pan myeloid growth factor that
stimulates Granu, - mono, megakaryocyte
and eosinophil progenitors.
GM-CSF
stimulates granulocytes production
and functional activation
G-CSF
mono, fibroblast ,
megakaryocytes
Meg-CSF
stimulates monocytes and
macrophages production activity
M-CSF
Target cells are pronormoblast (a form of an immature cells) and CFU-Erythroid cells
Erythropoietin
The entry of mature blood cells into the intravascular space relies upon
- multiplication
- gradual maturation
- orderly release
3 Possible Activities of HSCs
- Self-renewal
- Differentiation
- Apoptosis - refers to programmed cell death
group of specific glycoproteins
called growth factors that regulates the proliferation,
differentiation, and maturation of hematopoietic precursor cells
cytokines
Cytokines includes:
→ Interluekins (Ils)
→ Lymphokines
→ Monokines
→ Interferons
→ Colony Stimulating Factors (CSFs)
→ Chemokines
Positive Influence
- IL-1 - (inflammation)
- IL-3 – Multilineage (growth and hematopoietic)
- IL-6 – B cells (acute phase reactant)
- IL-9 (promote mast cell growth / function)
- IL11 – Megakaryocytes
- GM-CSF
- Kit Ligand
Negative Influence
- Transforming Growth
Factor-β - Tumor Necrosis
Factor-α - Interferons
Begins around the 19th day of embryonic development
after fertilization
Mesoblastic Phase / primitive hematopoiesis
Characterized by recognizable clusters of developing
erythroblasts, granulocytes, and monocytes colonizing the
fetal liver, thymus, spleen, placenta
Hepatic Phase / definitive hematopoiesis
surrounds the white pulp and forms a reticular
meshwork containing blood vessels,
macrophages, and specialized B cells
marginal zone
3 POSSIBLE ACTIVITIES OF HSCs
- Self-renewal
- Differentiation
- Apoptosis
organ responsible in the conditioning of T
lymphocytes
Thymus
storage site for platelets
spleen
spleen also known as
graveyard
