BLOOD

Department of histology, cytology and embryology

2013 medical students

Kharkov National Medical University

Blood: Blood: consists ofconsists of

««CellsCells»»::• Erythrocytes (RBC)Erythrocytes (RBC)• Leucocytes (WBC)Leucocytes (WBC)• Thrombocytes Thrombocytes

(Platelets)(Platelets)

++

PlasmaPlasma (fluid intercellular space)(fluid intercellular space)

““Cells” of the BLOODCells” of the BLOOD

Blood cells. Erythrocytes

ERYTHROCYTES

Amount in blood

Men - 3.9 - 5.5 ×1012/liter

Women - 3,7-4,9 ×1012/liter

ErythrocyteErythrocyte : :

• biconcavebiconcave discdisc

withwith average diameter average diameter

~~ 7 7 µmµm ((!!!!!!))..• does not contain a does not contain a

nucleusnucleus• is is filled with filled with

hemoglobinhemoglobin - the - the oxygen binding oxygen binding protein protein

function of function of ERYTHROCYTE: :

• carrcarriesies oxygenoxygen from from the lungs to the body the lungs to the body cellscells,,

• helps in carrying of helps in carrying of COCO22 from tissues to from tissues to

the lungsthe lungs• !!! NOTE!!! NOTE: : biconcave

shape improves exchange by decreasing of diffusions distance !!!

ERYTHROCYTESerythrocytes abnormalities :

•an erythrocyte, smaller than6 µm in diameter is termed amicrocyte;•whereas an erythrocyte larger

than normal (from 9 µm to 12 µm in diameter) is termed a macrocyte

Thus a shift in size range toward smaller erythrocytes is called a microcytic condition, and toward bigger ones, a macrocytic condition.

Smears of normal blood usually exhibit an occasional erythrocyte of abnormal shape. The general term for such a cell is a poikilocyte (Gr. poikilis, manifold).

Unisocytosis and Poikilocytosis Unisocytosis and Poikilocytosis

• 1 — 1 — discocytesdiscocytes - -normocytesnormocytes; ;

• 2 — 2 — MACROCYTEMACROCYTE; ; (may (may be microcyte, 2 types of be microcyte, 2 types of

un-iso-cytosisun-iso-cytosis))

• 3,4 — 3,4 — echinocytesechinocytes; ; • 5 — 5 — stomatocytestomatocyte; ; • 6 — 6 — sferocytessferocytes..

• 3-6 - 3-6 - poikilocytosispoikilocytosis3

5

1

6

PlateletsPlatelets

PlateletsPlatelets

They areThey are::• membrane-membrane-

bound sacsbound sacs, , fragments of fragments of cells;cells;

• 2 to 5 µm in 2 to 5 µm in diameter.diameter.

PLATELETS

Platelets Play a Key Role in the Arrest of Bleeding (Hemostasis, blood clotting)

PlateletsPlatelets

PlateletsPlatelets

• Consist of 2 zones:Consist of 2 zones:• -- peripher peripheral oneal one is called is called

the the HyalomereHyalomere..• The central The central one - one -

Granulomere. . • HyalomereHyalomere is a colorless is a colorless

and homogeneous.and homogeneous.• granulomeregranulomere contains contains

azure-colored granules.azure-colored granules.

PlateletsPlatelets

• The granules contain several different The granules contain several different substancessubstances::

• thromboplastinthromboplastin – promotes blood clotting – promotes blood clotting • serotoninserotonin – elicits pain – elicits pain

• platelet-derived growth factorplatelet-derived growth factor (PDGF) - (PDGF) - stimulates tissue regeneration stimulates tissue regeneration

LeucocytesLeucocytes

• True cells, True cells, have have nucleusnucleus, organelles , organelles and inclusions in and inclusions in granulesgranules

• ALL LeucocytesLeucocytes migrare from blood to connective tissue

• NucleusNucleus containes containes two to eight two to eight lobelobess

Classification:Classification:types by presence of granulestypes by presence of granules

!!! Totally 5 types of leucocytes !!! Totally 5 types of leucocytes

GranulocytesGranulocytes • neutrophils, neutrophils, • basophils,basophils,• eosinophilseosinophils

A-granulocytesA-granulocytes• monocytes, monocytes, • lymphocyteslymphocytes

BasophilsBasophils

BasophilsBasophils

• The The basophilicbasophilic granules are large, granules are large, stain stain deep bluedeep blue to to purplepurple, ,

• and are often and are often so so numerousnumerous that that they they mask the nucleus. mask the nucleus.

• Basophils constitute only approximately 0.5% of peripheral blood leukocytes.

BasophilsBasophils

• These granules These granules contain contain histaminehistamine (cause vasodilation) (cause vasodilation) and and heparinheparin (anticoagulant). (anticoagulant).

EosinophilsEosinophils

EosinophilsEosinophils• havehave large large acidophilicacidophilic

granulesgranules which which appear appear pinkpink (or (or redred). ).

• The granules contain The granules contain digestive enzymesdigestive enzymes that that are particularly effective are particularly effective against parasitic wormsagainst parasitic worms

• These cells also These cells also phagocytize phagocytize antigenantigen-antibody -antibody complexes.complexes.

EosinophilsEosinophils EM imageEM image

NeutrophilsNeutrophils

NeutrophilsNeutrophils

• 12 to 14 µm in 12 to 14 µm in diameter.diameter.

• GranulesGranules are pale are pale staining (staining (neutralneutral))

• They play They play primary primary role in role in inflammationinflammation..

• TheyThey are capable are capable for for phagocytphagocytosis osis ofof bacteriabacteria..

The segmented nucleus of most neutrophils consists of The segmented nucleus of most neutrophils consists of two to five lobes interconnected by fine strands of two to five lobes interconnected by fine strands of chromatin. chromatin.

In mature neutrophils, sex chromatin (where present) can In mature neutrophils, sex chromatin (where present) can sometimes be seen as a separate tiny lobe known as a sometimes be seen as a separate tiny lobe known as a drumstick appendagedrumstick appendage. .

The cytoplasm of mature neutrophils contains two kinds of The cytoplasm of mature neutrophils contains two kinds of granules granules

azurophilic granules and specific granules

NeutrophilNeutrophil, phagocyte, phagocyte

LymphocytesLymphocytes

LEUKOCYTES

Lymphocytes comprise 20% to 50% of the blood leukocytes

LymphocytesLymphocytes• NNucleusucleus is very largeis very large, , almost fills the cell leaving a almost fills the cell leaving a

very thin rim of cytoplasm. very thin rim of cytoplasm. • Function - Function - immune response. immune response.

• 2 types: 2 types: • The The B-lymphocytesB-lymphocytes:: go to connective tissue to go to connective tissue to

become become PLASMA CellPLASMA Cell.. produce antibodies produce antibodies, , • The The T-lymphocytesT-lymphocytes act against virus act against virus--infected cells infected cells

and tumor cells. and tumor cells.

LymphocytesLymphocytes

MonocytesMonocytes

MonocytesMonocytes

• - - are are the the largest largest amongamong the leukocytes the leukocytes,, about 20 about 20 µm in diameter and agranular. in diameter and agranular.

• The nucleus is most often The nucleus is most often U-shapedU-shaped or orkidneykidney-b-bean ean --shapedshaped, , or C-shapedor C-shaped

• the cytoplasm is abundant and light blue.the cytoplasm is abundant and light blue.

Monocytes comprise from 3% to 11% of the blood leukocytes

MonocytesMonocytes• These cells leave the blood These cells leave the blood

stream to become stream to become macrophagesmacrophages in conn. tissin conn. tiss. .

• macrophages play a role in macrophages play a role in inflammatory and inflammatory and  immune responses immune responses. .

• are antigen-presenting cellsare antigen-presenting cells(APC)(APC)

• They are They are phagocytesphagocytes, , defend the body against defend the body against viruses and bacteria.viruses and bacteria.

Complete Blood Count (CBC)Complete Blood Count (CBC)

Characteristics AmountHematocrit men 0,39-0,49Hematocrit women 0,35-0,45RBC men 4,0-5,0 х 1012/LRBC women 3,9-4,7 х 1012/LHb men 13-16 g/dLHB women 12-14 g/dLWBC 4-9 х 109/LPlatelets 180-320 х 109/L

White Blood Cell Differential Count

Basos Eos Segs Lymphs Monos

Myelo-cytes

Meta-myelo-cytes

Bands Seg-

mented

0-1% 0,5-5%

--- --- 1-6% 47-72% 19-37% 3-11%

Blood Cell formationBlood Cell formation(haemocytopoiesis)(haemocytopoiesis)

HaemopoiesisHaemopoiesis

• During fetal development, the formation of During fetal development, the formation of blood cells (blood cells (haemopoiesishaemopoiesis) begins in) begins in thethe wall of the yolk sacwall of the yolk sac. .

• After the second month of fetal After the second month of fetal development, the development, the liverliver, and, slightly later, , and, slightly later, the the spleenspleen, become the dominant sites of , become the dominant sites of haemopoiesis.haemopoiesis.

• From the From the 6th6th month the formation of blood month the formation of blood cells occurs cells occurs in bone marrowin bone marrow,,

Haemopoietic CellsHaemopoietic Cells• There are 6 classes of There are 6 classes of

Haemopoietic CellsHaemopoietic Cells

1 class1 class• StemStem cells – 1-st class cells – 1-st class

• -- -- self-replicatingself-replicating,, which can which can generate all types of blood cells. generate all types of blood cells.

2 class2 class• Progeny of Progeny of stem cellsstem cells may develop into either may develop into either

lymphoidlymphoid semi-stem cells ( semi-stem cells (gives rise to gives rise to lymphocyteslymphocytes)) or or myeloidmyeloid semi-stem cells semi-stem cells (gives rise to the major groups of blood cells (gives rise to the major groups of blood cells otherother than lymphocytes than lymphocytes ))

Note:Note: semi-stem cells: semi-stem cells:

• - are - are particularly determinedparticularly determined cells: cells: are capable to develop are capable to develop onlyonly into into

lymphocytes lymphocytes or onlyor only into all other blood into all other blood cells.cells.

• Development of blood cells from LSC is Development of blood cells from LSC is called called lymphopoiesis.lymphopoiesis.

• Development of blood cells from MSC is Development of blood cells from MSC is called called myelopoiesismyelopoiesis..

3 class is called3 class is called

• unipotential unipotential or …or …

• hemopoietin-sensitive cells. hemopoietin-sensitive cells.

Myeloid linesMyeloid lines

Myeloid semi-stem cell forms 4 kinds of Myeloid semi-stem cell forms 4 kinds of hemopoietin-sensitive cells:hemopoietin-sensitive cells:

• Erythropoietin-sensitiveErythropoietin-sensitive cell forms cell forms the the erythroiderythroid line line

• Leukopoietin-sensitive cell forms Leukopoietin-sensitive cell forms granulocytesgranulocytes lineline

• Monopoietin-sensitive cell forms Monopoietin-sensitive cell forms monocytemonocyte - - macrophages linemacrophages line

• Thrombopoietin-sensitive cellThrombopoietin-sensitive cell forms forms megakaryocytes megakaryocytes --- --- tthrombocytehrombocyte lineline

Lines of Lines of lymphopoiesislymphopoiesis

• B- lymphopoiesis B- lymphopoiesis

• T- lymphopoiesisT- lymphopoiesis

4-th class of Haemopoietic Cells4-th class of Haemopoietic Cells

• The first recognizable, actively dividing The first recognizable, actively dividing

cells that are called cells that are called blastblast cells. cells.

4. Haemopoietic Cells4. Haemopoietic Cells

There are There are sixsix types of blast cells: types of blast cells:

• Proerythroblast or simply erythroblast;Proerythroblast or simply erythroblast;

• Myeloblast;Myeloblast;

• B- lymphoblast;B- lymphoblast;

• Megakaryoblast;Megakaryoblast;

• MonoblastMonoblast

• T- lymphoblast;T- lymphoblast;

55thth class of Haemopoietic Cells class of Haemopoietic Cells

• - cell differentiation- cell differentiation

66thth class of Haemopoietic Cells class of Haemopoietic Cells

• Mature cellMature cell - leave RBM and Thymus and - leave RBM and Thymus and go to bloodstreamgo to bloodstream

Erythroid lineErythroid line

• The first identifiable stage of The first identifiable stage of erythropoiesis is the erythropoiesis is the proerythroblastproerythroblast - a - a large, slightly basophilic cell, which large, slightly basophilic cell, which contains a large, lightly stained nulceus. contains a large, lightly stained nulceus.

ErythrocytesErythrocytes

• Proerythroblasts differentiate to: Proerythroblasts differentiate to:

• basophilic erythroblastbasophilic erythroblast, ,

• polychromatophilicpolychromatophilic and and

• orthochromic normoblastsorthochromic normoblasts. .

• The nucleus is finally extruded from the The nucleus is finally extruded from the normoblastnormoblast. .

See: Erythrocytes of frog, See: Erythrocytes of frog,

• NucleatedNucleated• Primitive!Primitive!• In human – In human –

only during only during formation, in formation, in bone marrow - bone marrow - normoblastsnormoblasts

ReticulocyteReticulocyte

• youngyoung erythrocyteserythrocytes still contain some still contain some organelles, organelles,

• … … may enter may enter circulation circulation

• … … remain for a few remain for a few days in the bone days in the bone marrow to mature to marrow to mature to erythrocyteserythrocytes

ReticulocyteReticulocyte

Erythrocyte Erythrocyte is leaving is leaving

RBMRBM

GranulocytesGranulocytes

• MyeloblastsMyeloblasts proliferate to generate proliferate to generate promyelocytespromyelocytes. .

• PromyelocytesPromyelocytes begin to accumulate begin to accumulate nonspecificnonspecific granules, but they are still able to divide. The granules, but they are still able to divide. The maturation of their progeny, maturation of their progeny,

• … … the the MyelocytesMyelocytes, young leucocytes, are , young leucocytes, are characterised by the accumulation of characterised by the accumulation of specificspecific granules and changes in nuclear morphology.granules and changes in nuclear morphology.

• MetamyelocytesMetamyelocytes have C-shaped nucleus. have C-shaped nucleus.

Blood Platelets (Thrombocytes)Blood Platelets (Thrombocytes)

• Are Are formformeded from giant myeloid cells called from giant myeloid cells called megakaryocytesmegakaryocytes (60 to (60 to 160 µm in 160 µm in diameterdiameter). ).

• Cytoplasmic processes of thCytoplasmic processes of theesse e cellcellss extend into marrow sinuses and fragment extend into marrow sinuses and fragment away. These cellular fragments are the away. These cellular fragments are the platelets or thrombocytes.platelets or thrombocytes.

• Megakaryocytes are Megakaryocytes are in turn the product of in turn the product of the differentiation of the differentiation of basophilic basophilic megakaryoblastsmegakaryoblasts. .