WEEK 5 RBCS ppt ash.ppt

8/10/2019 WEEK 5 RBCS ppt ash.ppt

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Blood and Bone Marrow

Histology Dr. ashraf

mahmoud


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Blood is a specialized type of connective tissue.

It is composed of:

A-Blood cells 45 %which include the following:1-Red blood corpuscles (erythrocytes).

2-White blood cells (leucocytes).

3- Platelets (Thrombocytes).B-Plasma55%(fluid intercellular substance).

-In man, blood volume is about 5 liters.


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The blood plasma-Plasma is an aqueous solution containingplasma proteins,inorganic salts and severalorganic compounds such as vitamins, aminoacids and hormones.

-Plasma is in constant exchange with the extracellular fluids of the body.


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-Plasma proteins are of threecategories:

1-Albumins.2-Globulins.

3-Fibrinogens.

-Albumins can bind with insoluble fattyacids helping in their transport,

-globulins form antibodies of the immune

system and-fibrinogensform fibrin of the blood clot.


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A- In the embryothey are:1-Yolk sac mesoderm during the first twomonths.

2-Liver and spleen from the second to the fifthmonth.

3-Bone marrow from the fifth month onwards.

B- In the adult, haemopoiesis occurs in:

1-Bone marrow ( myeloid tissue) mainly ofthe skull, ribs,sternum, vertebrae, pelvis andproximal ends of long bone.

2-Lymphoid tissue.


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Types of bone marrow1-Red bone marrow

Red bone marrow is present in all bones ofthe foetus and in certain bones of adults

( mentioned above ).

2-Yellow bone marrow

yelloow bone marrow is present in adult

long bonesand is characterized by a high fat

content.

Yellow marrow can be changed into red one

in times of need.


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Examinationof bone marrow

Can be done by:

1-Bone marrow sections.

2-Bone marrow smears.

3-Marrow films.


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Structure of bone marrow

(myeloid tissue)

The myeloid tissue consists of:

I-Connective tissue stroma

II-The fixed stromal cells include:

III-Free haemopoietic cells:

f


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Structure of bone marrow

(myeloid tissue)

The myeloid tissue consists of:

I-Connective tissue stroma: containing bloodsinusoids.

The stroma is made up of reticular networkcontaining blood sinusoids, venules and arterioles.

The blood sinusoids have fenestrated endothelialcells with occludent junctions in between these cells.


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II-The fixed stromal cells include:

1-Reticular cells

They are branched cells with pale nucleus and palecytoplasm. They produce reticular fibres, secreting

type III collagen.Reticular cells have some phagocytic activity andmay have a role in immunological response.

2-Fibroblasts

Secretes collagen that supports the blood vessels andthe stroma.


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3-Macrophages

They are derived from monocytes.

These macrophages have pseudopodia whichare able to extend between endothelial cells toengulf any foreign body in the blood.

4-Fat cells.

5-Osteogenic cellslining the bone trabeculae.

6-Endothelial cells lining the blood sinusoids,venules and arteriole


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III-Free haemopoietic cells:

All types of developing blood cells are

present in the meshes of the reticular

stroma.


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The pluripotential stem cells

-They are present in a pool and are able toproduce all types of blood cells.

These stem cells resemble lymphocytes with adiameter of 7 m and a large rounded nucleushaving prominent nucleoli. Their cytoplasm

contains many ribosomes but few mitochondriaand rER.


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The pluripotential stem cells proliferate and form:

I-Myeloid multipotential cells:which will become:

-Erythrocytes.

- Granulocytes.-Monocytes.

-Megakaryocytes.

II-Lymphoid multipotential cells: which willbecome: -Lymphocytes.


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II-Lymphoid multipotentialcells

which will become:

-Lymphocytes.

-These stem cells proliferate and form lesspotential cells (progenitor cell)

-Progenitor cellsare unipotential or bipotential

-Precursor cells( e.g. lymphoblasts anderythroblasts ) produce mature cells


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RED BLOOD CORPUSCLES


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RED BLOOD CORPUSCLES

RBC d Bl di Di d


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RBC and Bleeding Disorders

NORMAL

Anatomy, histology

Development

Physiology

ANEMIAS

Blood loss: acute, chronic

Hemolytic

Diminished erythropoesis

POLYCYTHEMIA

BLEEDING DISORDERS


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Peripheral Blood: Erythrocytes

RBCs constitute thelargest number ofcells in the blood

Biconcave discs

NO NUCLEUS

ContainHemoglobin

I RED BLOOD CORPUSCLES
http://www.jdaross.mcmail.com/images/erythrocytes.jpghttp://www.jdaross.mcmail.com/images/erythrocytes.jpg


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I-RED BLOOD CORPUSCLES(ERYTHROCYTES)

1-Shape

-It is round biconcavecorpuscle in side view, known

as a dumb bell shape bell shape.-Thebiconcave shape provides a large surface area

for gas exchanges.

-In the human it is round non-nucleated-Such corpuscles may coalesce together by their sideforming the rouleaux appearance.


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Abnormalities in the shape

A-Crenation:-it means loss of the water contents

from the R.B.C.resulting in decreasing itssize and irregularities in its shape.

B Heamolysis:


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B-Heamolysis:

-It means loss of the corpuscularhemoglobin as result of its rupture.

-The main causes of heamolysis are:

1-Hyponotic solutions.

2-Incompatible blood transfusion.3-Toxins.

C-Poikilocytosis:

The R.B.C takes the pear shape.D-Sickle shaped cell:

The corpuscle takes the shape of a crescent.

RBC


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RBC


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2-Size

-Diameter:7.5 micrometers with a rangebetween (6-8um).

-Thickness: 1.9 microns.


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Abnormalities in the size

A-Macrocyte:The diameter is more than 8

micrometers.

B-Microcyte:

The diameter is smaller than 6micrometers.


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C-Spherocyte:

The thickness of the corpuscle is morethan 1.9 micrometers.

D-Anisocytosis:It is variation in the size of the R.B.C. in theblood of the

same person. Such variation is detected byPrice Jones curve.

3 C t


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3-Count

-The normal count of the red blood corpuscleis always done in one cubic millimeter of

blood.

*In the male it is about 5-5.5 million /1 ul *In the female it is about 4.5 millions /1 ul.

-The red blood cells count is done by special

apparatus called heamocytometer or by the

automated methods.

Abno malities in the co nt


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Abnormalities in the count

A-Increase in the number

( Polycythaemia)

Causes: -Primary, without a definite cause.

-Secondary due to low oxygen tension.Muscular exercise.

Pregnancy.

High altitude.Heart disease.

Cold bath.

Heavy meals.

B-Decrease in the number


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B-Decrease in the number(oligocythaemia)

Causes: Hemorrhage.Heamolysis.

Idiopathic.

Aplastic due to bone marrow defect.Deficiency of one of the major factors forRBCs development e.g iron or B12.

4 C l


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4-Color-Fresh blood when spreaded appear yellowish

greenin color but thick drop of blood appearredin color due to condensation of large

number of the R.B.C. over each other.

-The color of the blood is due to the red

pigment hemoglobin which appear deeper in

the peripheral part of the corpuscle and pale inits central part due to reduced thickness of the

corpuscle.

-The normal color is called Normochromic.


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Abnormalities in the color

A-Hypochromic:

The amount of the hemoglobin is less than the

normal concentration.B-Hyperchromic:

The amount of the hemoglobin is more than

the normal concentration.C-Stippling:

Bluish dots considered as precipitation of the

the stain.

D-Polychromasia:


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D Polychromasia:

The corpuscle contains undiffused heam-oglobin, so double colors can be seen, the theblue color of the cytoplasm and the red color ofthe HB.

E-Cabot ring:

It is a remnant of the nuclear membrane.

F-Howel jolly bodies:

They are remnants of the chromatinof the nucleus.


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5-Structure


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5-Structure

-Erythrocytes have flexible cell membranes, which

contain lipids, proteins and carbohydrates.

-The membrane peripheral proteins (spectrins) are

responsible for the shape of the erythrocyte and help intheir flexibility on passing through capillaries.

-Erythrocytes contain haemoglobin 33%,water 66%and some enzymes needed for glucose metabolism.Haemoglobin is aconjugated protein formed of globinand haematin.


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-By EM, erythrocytes are highly electron densedue to their iron content.

-Haemoglobin can combine with O2 oxyhaemoglobin or CO2

carbaminohaemoglobin.

These combinations are reversible.-Haemoglobin may combine with CO carboxyhaemoglobin which is irreversible.


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6-Fate

-Normally, the life span of human erythrocytes is 120days.

- erythrocytes are removed from the circulation by

macrophages of the spleen and bone marrow.-Haemoglobinis destructed to globin and haematin.

-Haematin is furtherly broken into haemosidrin

(which is reused to form haemoglobin in the liver )and haematoidin ( bilirubin ) which is excreted in

bile.

R ti l t


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Reticulocytes

-They are immature form of erythrocytes in theblood released from the bone marrow.

-Their normal percentage in blood is about 1 %

of the circulating red blood cells.-Microscopically, they cannot be differentiatedfrom ordinary erythrocytes in a blood film.They need special incubation (supravital

staining) by brilliant cresyl blue.

-


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-Reticulocytes increase in cases ofincrease demand for erythrocytesformation from bone marrow as inhaemorrhages.

EM, their cytoplasm appears less electrondense due to less haemoglobin content.

-Reticulocytes show remnants ofribosomes, mitochondria and Golgi.

MATURATION OF RED BLOOD CELLS


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MATURATION OF RED BLOOD CELLS1-pluripotential stem cell

myeloid multipotentialcells.2- erythrocyte- colony forming cells

3-Proerythroblas

4-basophilic erythroblasts ts

5-polychromatophilic erythroblasts

6-normoblasts

7-reticulocyte

8-er throc te

ERYTHROPOIESIS


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ERYTHROPOIESISMATURATION OF RED BLOOD CELLS

1-Thepluripotential stem cellsof the bonemarrow proliferate and form myeloidmultipotentialcells.

2-These cells form the progenitor daughtercells, erythrocyte- colony forming cells

(ECFC) which differentiate intoproerythroblasts.

3-Proerythroblasts are the first recognizable


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3 Proerythroblasts are the first recognizable

cells of the erythrocytic series.

They are large cells ( 12-15 m ) with large

moderately stained nuclei having prominent

nucleoli and their cytoplasm is basophilic.

4-Proerythroblasts differentiate into basophilic

erythroblasts which is smaller ( 10-12 m )

than proerythroblast having a smaller

condensed nucleus and basophilic cytoplasm.


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5-Basophilic erythroblasts differentiateinto polychromatophilic erythroblasts

which is smaller than basophilic erythroblastswith a small more condensed nucleus.

The cytoplasm is polychromatophilic due tothe presence of polysomes ( basophilic ) andhaemoglobin ( acidophilic ).

Mitosis occurs in proerythroblasts,basophilicand polychromatophilic erythroblasts.


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6-Polychromatophilic erythroblasts

differentiates tonormoblasts

which are smaller in diameter ( 8-10 m )having darkly stained eccentric nuclei.

The cytoplasm is acidophilic due to thepresence of haemoglobin.


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7-The nucleus of normoblast

is extruded to the outside to be phagocytosed bymacrophages and the cell now is calledreticulocyte. Reticulocytes are slightly largerthan mature erythbrocutes. Their number is

1-2 % of blood erythroblasts.

They have blue network which is the remnants

of polysomes.They stain positively with the supravital stainbrilliant cresyl blue.


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8-The reticulocyteloses its polyribosomes and becomes mature

erythrocytebeing a biconcave disc-shaped full ofhemoglobin. Mature erythrocytes pass through theendothelium of blood sinusoids to the generalcirculation.

-The development of erythrocytes is under the

control of erythropietin and it needs iron, folic acidand vit. B12.

-Erythropoiesis takes about 7 days to produce

mature cells.

RBC Development


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RBC Development

Proerythroblast


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Proerythroblast

Biggest in lineage Large central nucleus

with one or two

nucleoliBasophilic cytoplasm

b/c ribosomes

Look for Golgi ghost

Basophilic Erythroblast


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Basophilic Erythroblast

Smaller thanproerythroblast

Checkerboardnucleus(heterochromatic)

Intense basophilia(lots of ribosomes!)

Proerythroblast vs Basophilic


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y pErythroblast

Polychromatophilic Erythroblast


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Polychromatophilic Erythroblast

Smaller than basophilicerythroblast

Smaller intensely

heterochromaticnucleus

Purple/lilac cytoplasm

mix of basophiliafrom ribosomes andgrowing eosinophilia

from hemoglobin

Normoblast


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Normoblast

Smaller thanpolychromatophilicerythroblast

Small, compact,

intensely stainingnucleus that is gettingready to be extruded

Eosinophilic cytoplasm

due to abundanthemoglobin


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Reticulocyte

Immature RBC thathas polyribosomes

Appear as polychrom-atophilic erythrocyteon blood smear

When stained with aspecial (supravital)stain Reticulocyte

Erythrocyte


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Erythrocyte

Smallest

Eosinophilicdue tohemoglobin

NONUCLEUS!


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Sickle Cell Disease


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Sickle Cell Disease Classic hemoglobinopathy

Normal HGB is 2 2: -chain defects(Val->Glu)

Reduced hemoglobin sickles inhomozygous

8% of American blacks are heterozygous

THALASSEMIAS


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THALASSEMIASA WIDE VARIETY of diseases involving GLOBIN

synthesis, COMPLEX genetics

Alphaor betachains deficient synthesis

involved Often termed MAJOR or MINOR, depending on

severity, silent carriers and traits are seen

HEMOLYSIS is uniformly a feature, a microcyticanemia

A crew cut skull x-ray appearance may beseen

RBC LAB


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RBC LAB

WEEK 5 RBCS ppt ash.ppt

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