ERYTHROPOIESISERYTHROPOIESIS

DR. LAXMIKANTA SAYDR. LAXMIKANTA SAY

HAEMOPOIESISHAEMOPOIESIS

A process of origin, development and maturation of erythrocytes.

CHANGES DURING ERYTHROPOIESIS Reduction in size of cell From diameter 25 to

7.5µm Disappearance of Nucleoli & nucleus Appearance of Hemoglobin Change in staining properties of cytoplasm

DEFINITIONDEFINITION

AGE SITESEarly weeks of Embryonic life

Yolk Sac

Middle of trimester gestation

Liver & spleen and lympnodes

Last trimester of gestation Bone marrow

After Birth to 5 Years of life

All bones

5 to 20 years of life All bones except proximal portion of Humerus & Tibia

More than 20 years Marrow of membranous bones as Vertebrae , sternum, ribs& iliac

Production sites Production sites

Production sites Production sites

GENESIS OF GENESIS OF ERYTHROPOIESISERYTHROPOIESIS

Haemocytoblast (stem Cell)Haemocytoblast (stem Cell)

Cell size – 19-23 µmCell size – 19-23 µm NucleusNucleus - Very big- Very big - occupies almost whole of cell with open - occupies almost whole of cell with open

chromatinchromatin - 4-5 nucleoli- 4-5 nucleoli CytoplasmCytoplasm - Rim all around the nucleus; deep basophilic- Rim all around the nucleus; deep basophilic

Mitosis – (++)Mitosis – (++)

PRO-ERYTHROBLAST(NORMOBLAST)PRO-ERYTHROBLAST(NORMOBLAST)

Cell size - 14-19 µmCell size - 14-19 µm

Nucleus Nucleus

- very big, - very big,

- occupies ¾ of cell volume - occupies ¾ of cell volume

- 2-3 nucleoli; chromatin - 2-3 nucleoli; chromatin open open

Cytoplasm Cytoplasm

- scanty , only a rim around - scanty , only a rim around the nucleus; deep basophilicthe nucleus; deep basophilic

EARLY -NORMOBLASTEARLY -NORMOBLAST

Cell size 10-14µmCell size 10-14µm Nucleus Nucleus

- size decreases than its - size decreases than its precursor; precursor;

- chromatin further - chromatin further condensescondenses

Cytoplasm Cytoplasm

- amount increases, less - amount increases, less basophilicbasophilic

INTERMEDIATE INTERMEDIATE NORMOBLASTNORMOBLAST

Cell size - 10-14µmCell size - 10-14µm Nucleus Nucleus

-size further decrease; -size further decrease; chromatin further chromatin further condensescondenses

Cytoplasm Cytoplasm

- marked,- marked,

- polychromatophilic - polychromatophilic staining due to appearance staining due to appearance

of of haemoglobinhaemoglobin

LATE NORMOBLASTLATE NORMOBLASTEarly NormoblastEarly Normoblast

Cell size 7-10µmCell size 7-10µm Nucleus sizeNucleus size

- very small with - very small with chromatin dot chromatin dot cart cart wheel appearancewheel appearance

CytoplasmCytoplasm

- markedly increase- markedly increase HaemoglobinHaemoglobin

– – further increases in further increases in amountamount

Late NormoblastLate Normoblast

Cell size 7 – 8 µmCell size 7 – 8 µm Nucleus Nucleus

- degenerates, becomes - degenerates, becomes uniformly stained pyknoticuniformly stained pyknotic

CytoplasmCytoplasm

- further increase; more - further increase; more acidic, less basophilicacidic, less basophilic

HaemoglobinHaemoglobin

– – further increases in further increases in amountamount

RETICULOCYTESRETICULOCYTES Immature RBC slightly larger Immature RBC slightly larger

than mature RBC.than mature RBC. Cell sizeCell size - 7-8 µm, No nucleus- 7-8 µm, No nucleus - Named due to presence of - Named due to presence of

reticular network or reticular network or reticulum of disintegrated reticulum of disintegrated organelle.organelle.

CytoplasmCytoplasm - Acidophilic- Acidophilic Newborn counts 2-6%,less Newborn counts 2-6%,less

than 1% in normal adults.than 1% in normal adults.

MATURE ERYTHROCYTEMATURE ERYTHROCYTE Reticular network Reticular network

disappears & cell become disappears & cell become matures RBC & attains matures RBC & attains shape biconcave shape.shape biconcave shape.

Mature RBC is with Mature RBC is with hemoglobin & with out hemoglobin & with out nucleus.nucleus.

Requires 9 days for Requires 9 days for development & maturation development & maturation of RBC .of RBC .

Requires 7 days to the Requires 7 days to the stage of reticlocyte and 2 stage of reticlocyte and 2 days for maturation to RBC.days for maturation to RBC.

Tissue oxygenationTissue oxygenation-blood flow-blood flow

-blood hemoglobin concentration-blood hemoglobin concentration

-hemoglobin oxygen saturation-hemoglobin oxygen saturation EPO(Erythropoietin)EPO(Erythropoietin) Hematopoietic CytokinesHematopoietic Cytokines Colony stimulating factorsColony stimulating factors GM-CSF(Granulocyte macrophage colony GM-CSF(Granulocyte macrophage colony

stimulating factor)stimulating factor) Thrombopoietin and stem cell factorThrombopoietin and stem cell factor IL-1,IL-3,IL-IL-6IL-1,IL-3,IL-IL-6

CONTROL OF ERYTHROPISISCONTROL OF ERYTHROPISIS

BIO-SYNTHESIS OF HEMOGLOBINBIO-SYNTHESIS OF HEMOGLOBIN GENERAL FACTORSGENERAL FACTORS

-Erythropoietin-Erythropoietin

-Thyroxine-Thyroxine

-Hemopoietic growth factors-Hemopoietic growth factors

-Vitamins.-Vitamins.

MATURATION FACTORSMATURATION FACTORS

-Vit.B12-Vit.B12

-Intrinsic factor -Intrinsic factor

-Folic acid-Folic acid

FOR HEMOGLOBIN FOR HEMOGLOBIN FORMATIONFORMATION

- First class protein & amino - First class protein & amino acidsacids

- Iron, Copper, - Iron, Copper,

- Cobalt & Nickel- Cobalt & Nickel

VITAMINSVITAMINS

-Vit-C-Vit-C

-Riboflavin-Riboflavin

-Nicotinic acid-Nicotinic acid

-Pyridoxin-Pyridoxin

ErythropoietinErythropoietin Haemopoietin Haemopoietin or Erythrocyte stimulating factor or Erythrocyte stimulating factor Chemistry Chemistry

- glycoprotein ( 74% protein & 26% carbohydrate)- glycoprotein ( 74% protein & 26% carbohydrate)

- contains 165 aminoacids- contains 165 aminoacids

- MW. 46,000- MW. 46,000 Source of secretionSource of secretion

- interstial cells of peritubular capillaries of - interstial cells of peritubular capillaries of kidneykidney, , also in also in LiverLiver & & BrainBrain

StimulantStimulant - Hypoxia - Hypoxia ActionsActions of Erythropoietin of Erythropoietin

- production, development & release of mature RBCs.- production, development & release of mature RBCs.

EFFECT OF HYPOXIAEFFECT OF HYPOXIA

THANK YOUTHANK YOU