hemopoesis ppt

8/12/2019 hemopoesis ppt

1/31

HEMOPOIESIS &

ERYTHROPOIESIS


2/31

HEMOPOIESIS: INTRO

Hemo: Referring to blood cells

Poiesis: The development or production of

The word Hemopoiesis refers to the production &

development of all the blood cells: Erythrocytes: Erythropoiesis

Leucocytes: Leucopoiesis

Thrombocytes: Thrombopoiesis.

Begins in the 20thweek of life in the fetal liver &spleen, continues in the bone marrow till youngadulthood & beyond!


3/31

Appendicular

skeleton:

Bones of the

Upper & Lower

limbs

In Adults active

hemopoietic marrow is

found only in:

The axial skeleton

The proximal ends of theappendicular skeleton.

SITES OF HEMOPOIESIS

Active Hemopoietic

marrow is found, in

children throughout

the:

Axial skeleton:

Cranium

Ribs.

Sternum

Vertebrae

Pelvis


4/31

STEM CELL THEORY

The dazzling array of all the blood cells are

produced by the bone marrow.

They all come from a single class of primitive

mother cells called as: PLURIPOTENT STEM CELLS.

These cells give rise to blood cells of:

Myeloid series: Cells arising mainly from the bonemarrow.

Lymphoidseries: cells arising from lymphoid

tissues.


5/31

CLONAL HEMOPOIESIS

PLURIPOTENT STEM CELL

STEM CELL

MULTIPLICATION COMMITTMENT

COMMITTED

STEM CELL

COMMITTED

STEM CELL

MULTIPLICATION

PROGENITOR

CELL

CFU: COLONY

FORMING UNIT


6/31

CLONAL HEMOPOIESIS: (Contd)

COLONY FORMING UNIT(CFU)

INTERMEDIATE

BLAST CELLS

MATURE BLOOD CELLS

END CELLS: FINITE LIFE SPAN

MORPHOLOGICALLYRECOGNIZABLE


7/31

STEM CELLS

These cells have extensive proliferative

capacity and also the:

Ability to give rise to new stem cells (Self

Renewal) Ability to differentiate into any blood cells lines

(Pluripotency)

They grow and develop in the bone marrow.

The bone marrow & spleen form a supportingsystem, called the

hemopoietic microenvironment


8/31

Pluripotent Stem cells: Has a diameter of 1823 .

Giving rise to: both Myeloid and Lymphoid seriesof cells

Capable of extensive self-renewal. Myeloid Stem cells: Generate myeloid cells:

Erythrocytes

Granulocytes: PMNs, Eosinophils & Basophils.

Thrombocytes. Lymphoid Stem cells: Giving rise only to:

Lymphocytes: T type mainly.

STEM CELLS: Types


9/31

PROGENITOR CELLS

Committed stem cells lose their capacity for

self-renewal.

They become irreversibly committed.

These cells are termed as Progenitor cells

They are regulated by certain hormones or

substances so that they can:

Proliferate Undergo Maturation.


10/31

CELL LINE REGULATORS

CELL LINE REGULATOR

ERYTHROID: BFU-E:

CFU : E

BURST PROMOTING ACTIVITY

ERYTHROPOIETIN

GRANULOCYTE-MONOCYTE:CFU-GM

COLONY STIMULATINGFACTOR(CSF)

MEGAKARYOCYTES: CFU-M MEGAKARYOCYTICSTIMULATING ACTIVITY

MEGAKARYOCYTES THROMBOPOIETIN


11/31

BLOOD CELLS: DEVELOPMENT

PROGENITORCELLS

LYMPHOIDCELLS

PRONORMOBLAST

MEGAKARYOBLAST MYELOBLAST MONOBLAST

LYMPHOCYTES ERYTHROCYTES THROMBOCYTES GRANULOCYTES MONOCYTES


12/31

ERYTHROPOIESIS:

SITES/PHASES

INTRAUTERINELIFE: INTRAVASCULAR PHASE:Upto 3rdmonth of

Intra Uterine Life.Endothelial cells = = = RBCs

HEPATIC PHASE: 3rdto 5th month IULLiver SpleennRBCs from Mesenchymal cells.

MYELOID PHASE: From 5thmonth of IULonwards.


13/31

POST NATAL LIFE:

CHILDREN:

Predominantly Red Bone Marrow of skeleton:

Axial &

Appendicular.

ADULTS:

Red Bone Marrow of Axial Skeleton.

ERYTHROPOIESIS: SITES/PHASES

contd.


14/31

PROERYTHROBLAST

BASOPHILICERYTHROBLAST

POLYCHROMATOPHILICERYTHROBLAST

ORTHOCHROMATICERYTHROBLAST

RETICULOCYTE

MATURE ERYTHROCYTES

ERYTHROPOIESIS


15/31

FACTORS REGULATING

ERYTHROPOIESIS

SINGLE MOST IMPORTANT REGULATOR:

TISSUE OXYGENATION

BURST PROMOTING ACTIVITY

ERYTHROPOIETIN

IRON

VITAMINS:

Vitamin B12

Folic Acid

MISCELLANEOUS


16/31

ERYTHROPOIETIN

A hormone produced by the Kidney.A circulating GlycoproteinNowadays available as Synthetic EpoietinActs mainly on CFU E. Increases the number of:

Nucleated precursors in the marrow. Reticulocytes Mature Erythrocytes in the

blood.


17/31

VITAMINS

B12: Cyanocobalamine Folic Acid: Is also called Extrinsic Factor of Castle. Needs the Intrinsic Factorfrom the Gastric juice

for absorption from Small Intestine. Deficiency causes Pernicious (When IF is

missing) or Megaloblastic Anemia. Stimulates Erythropoiesis Is found in meat diary products.


18/31

IRON

Essential for the synthesis of Hemoglobin.Deficiency causes Microcytic, Hypochromic

Anemia.TheMCV, Color Index MCHare low.


19/31

ERYTHROPOIESIS: SEQUENTIAL CHANGES

I II III IV V

VIPRONORMOBLAST

EARLYNBLAST

INTERNBLAST

LATENBLAST

RETICULOCYTE

MATURERBC

MITOCHONDRIA

BASOPHILIA

HEMOGLOBIN


20/31

ERYTHROID PROGENITOR CELLS

BFU-E: Burst Forming Unit Erythrocyte: Give rise each to thousands of nucleated

erythroid precursor cells, in vitro. Undergo some changes to become the Colony

Forming Units-Erythrocyte (CFU-E) Regulator: Burst Promoting Activity (BPA)


21/31

CFU-E: Colony Forming Unit- Erythrocyte:Well differentiated erythroid progenitor cell. Present only in the Red Bone Marrow. Can form upto 64 nucleated erythroid precursorcells. Regulator: Erythropoietin.

Both these Progenitor cells cannot bedistinguished except by in vitro culturemethods.

ERYTHROID PROGENITOR CELLS


22/31

Normoblastic Precursors

PROERYTHROBLAST: Large cell: 15 20 Microns in diameter. Cytoplasm is deep violet-blue staining Has no Hemoglobin. Large nucleus 12 Microns occupies 3/4thof the

cell volume. Nucleus has fine stippled reticulum manynucleoli.


23/31

EARLY NORMOBLAST:

Smaller in size.

Shows active Mitosis.

No nucleoli in the nucleus.

Fine chromatin network with few

condensation nodes found.

Hemoglobin begins to form.

Cytoplasm still Basophilic.



24/31

INTERMEDIATE NORMOBLAST:

Has a diameter of 1014 Microns.

Shows active Mitosis.

Increased Hemoglobin content in the

cytoplasm

Cytoplasm is Polychromatophilic.



25/31

LATE NORMOBLAST:

Diameter is 710 Microns.

Nucleus shrinks with condensed

chromatin.

Appears like a Cartwheel

Cytoplasm has a Eosinophilic appearance.



26/31

RETICULOCYTE:

The penultimate stage cell.

Has a fine network of reticulum like a

heavy wreath or as clumps of dots This is the remnant of the basophilic

cytoplasm, comprising RNA.

In the Neonates, Count is 26/Cu.mm.

Falls to


27/31

MATURE ERYTHROCYTE:

Biconcave disc.

No nucleus.

About One-third filled with Hemoglobin.



28/31

Regulation of Erythropoiesis

CFU

E

ProerythroblastsMature Erythrocytes

Tissue OxygenationFactors decreasing:

Hypovolemia Anemia

Poor blood flow Pulmonary Disease

ERYTHROPOIETINDecreases

Stimulates

An exampleof a

Negativefeed backmechanism


29/31

HEMOPOIESIS: REVIEW I

Hemopoiesis: Production of bloodcells.

Site: Predominantly in the BoneMarrow.

Both axial & appendicular skeletons. Erythropoiesis: Production of

Erythrocytes. Leucopoiesis: Production of

Leucocytes. Thrombopoiesis: Production of

Thrombocytes.


30/31

HEMOPOIESIS: REVIEW II

Cell lines:

Pluripotent Stem Cell

Progenitor Stem Cells: Committed

Proerythroblasts

Myeloblasts

Monoblasts

Lymphoid cellsMegakaryoblasts


31/31

hemopoesis ppt

Documents

Transcript of hemopoesis ppt