Transcript Blood

Kharkov National Medical University
BLOOD
Department of histology, cytology
and embryology
2013 medical students
Blood: consists of
«Cells»:
• Erythrocytes (RBC)
• Leucocytes (WBC)
• Thrombocytes
(Platelets)
+
Plasma
(fluid intercellular space)
“Cells” of the BLOOD
Blood cells. Erythrocytes
ERYTHROCYTES
Amount in blood
Men - 3.9 - 5.5 ×1012/liter
Women - 3,7-4,9 ×1012/liter
Erythrocyte :
• biconcave disc
with average diameter
~ 7 µm (!!!).
• does not contain a
nucleus
• is filled with
hemoglobin - the
oxygen binding
protein
function of ERYTHROCYTE:
• carries oxygen from
the lungs to the body
cells,
• helps in carrying of
CO2 from tissues to
the lungs
• !!! NOTE: biconcave
shape improves
exchange by
decreasing of
diffusions distance !!!
ERYTHROCYTES
erythrocytes abnormalities :
• an erythrocyte, smaller than
6 µm in diameter is termed a
microcyte;
• 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
• 1 — discocytes normocytes;
• 2 — MACROCYTE; (may
be microcyte, 2 types of
un-iso-cytosis)
• 3,4 — echinocytes;
• 5 — stomatocyte;
• 6 — sferocytes.
1
3
• 3-6 - poikilocytosis
6
5
Platelets
Platelets
They are:
• membranebound sacs,
fragments of
cells;
• 2 to 5 µm in
diameter.
PLATELETS
Platelets Play a Key Role in the Arrest
of Bleeding (Hemostasis, blood clotting)
Platelets
Platelets
• Consist of 2 zones:
• - peripheral one is called
the Hyalomere.
• The central one Granulomere.
• Hyalomere is a colorless
and homogeneous.
• granulomere contains
azure-colored granules.
Platelets
• The granules contain several different
substances:
• thromboplastin – promotes blood clotting
• serotonin – elicits pain
• platelet-derived growth factor (PDGF) stimulates tissue regeneration
Leucocytes
• True cells, have
nucleus, organelles
and inclusions in
granules
• ALL Leucocytes
migrare from blood to
connective tissue
• Nucleus containes
two to eight lobes
Classification:
types by presence of granules
!!! Totally 5 types of leucocytes
Granulocytes
• neutrophils,
• basophils,
• eosinophils
A-granulocytes
• monocytes,
• lymphocytes
Basophils
Basophils
• The basophilic
granules are large,
stain deep blue to
purple,
• and are often so
numerous that they
mask the nucleus.
• Basophils constitute
only approximately
0.5% of peripheral
blood leukocytes.
Basophils
• These granules
contain histamine
(cause vasodilation)
and heparin
(anticoagulant).
Eosinophils
Eosinophils
• have large acidophilic
granules which appear
pink (or red).
• The granules contain
digestive enzymes that
are particularly effective
against parasitic worms
• These cells also
phagocytize
antigen-antibody
complexes.
Eosinophils
EM image
Neutrophils
Neutrophils
• 12 to 14 µm in
diameter.
• Granules are pale
staining (neutral)
• They play primary
role in inflammation.
• They are capable for
phagocytosis of
bacteria.
The segmented nucleus of most neutrophils consists of
two to five lobes interconnected by fine strands of
chromatin.
In mature neutrophils, sex chromatin (where present) can
sometimes be seen as a separate tiny lobe known as a
drumstick appendage.
The cytoplasm of mature neutrophils contains two kinds of
granules
azurophilic granules and specific granules
Neutrophil, phagocyte
Lymphocytes
LEUKOCYTES
Lymphocytes
comprise 20%
to 50% of the
blood
leukocytes
Lymphocytes
• Nucleus is very large, almost fills the cell leaving a
very thin rim of cytoplasm.
• Function - immune response.
• 2 types:
• The B-lymphocytes: go to connective tissue to
become PLASMA Cell. produce antibodies,
• The T-lymphocytes act against virus-infected cells
and tumor cells.
Lymphocytes
Monocytes
Monocytes
• - are the largest among the leukocytes, about 20
µm in diameter and agranular.
• The nucleus is most often U-shaped or
kidney-bean -shaped, or C-shaped
• the cytoplasm is abundant and light blue.
Monocytes comprise from 3% to 11% of the blood
leukocytes
Monocytes
• These cells leave the blood
stream to become
macrophages in conn. tiss.
• macrophages play a role in
inflammatory
and immune responses.
• are antigen-presenting cells
(APC)
• They are phagocytes,
defend the body against
viruses and bacteria.
Complete Blood Count (CBC)
Characteristics
Hematocrit men
Hematocrit women
RBC men
RBC women
Hb men
HB women
WBC
Platelets
Amount
0,39-0,49
0,35-0,45
4,0-5,0 х 1012/L
3,9-4,7 х 1012/L
13-16 g/dL
12-14 g/dL
4-9 х 109/L
180-320 х 109/L
White Blood Cell Differential Count
Basos Eos
0-1%
0,55%
Segs
Myelocytes
Metamyelocytes
Bands
---
---
1-6%
Lymphs Monos
Segmented
47-72%
19-37%
3-11%
Blood Cell formation
(haemocytopoiesis)
Haemopoiesis
• During fetal development, the formation of
blood cells (haemopoiesis) begins in the
wall of the yolk sac.
• After the second month of fetal
development, the liver, and, slightly later,
the spleen, become the dominant sites of
haemopoiesis.
• From the 6th month the formation of blood
cells occurs in bone marrow,
Haemopoietic Cells
• There are 6 classes of
Haemopoietic Cells
1 class
• Stem cells – 1-st class
• -- self-replicating, which can
generate all types of blood cells.
2 class
• Progeny of stem cells may develop into either
lymphoid semi-stem cells (gives rise to
lymphocytes) or myeloid semi-stem cells
(gives rise to the major groups of blood cells
other than lymphocytes )
Note: semi-stem cells:
• - are particularly determined cells:
are capable to develop only into
lymphocytes or only into all other blood
cells.
• Development of blood cells from LSC is
called lymphopoiesis.
• Development of blood cells from MSC is
called myelopoiesis.
3 class is called
• unipotential or …
• hemopoietin-sensitive cells.
Myeloid lines
Myeloid semi-stem cell forms 4 kinds of
hemopoietin-sensitive cells:
• Erythropoietin-sensitive cell forms the erythroid
line
• Leukopoietin-sensitive cell forms granulocytes
line
• Monopoietin-sensitive cell forms monocyte macrophages line
• Thrombopoietin-sensitive cell forms
megakaryocytes --- thrombocyte line
Lines of lymphopoiesis
• B- lymphopoiesis
• T- lymphopoiesis
4-th class of Haemopoietic Cells
• The first recognizable, actively dividing
cells that are called blast cells.
4. Haemopoietic Cells
There are six types of blast cells:
• Proerythroblast or simply erythroblast;
• Myeloblast;
• B- lymphoblast;
• Megakaryoblast;
• Monoblast
• T- lymphoblast;
5th class of Haemopoietic Cells
• - cell differentiation
6th class of Haemopoietic Cells
• Mature cell - leave RBM and Thymus and
go to bloodstream
Erythroid line
• The first identifiable stage of
erythropoiesis is the proerythroblast - a
large, slightly basophilic cell, which
contains a large, lightly stained nulceus.
Erythrocytes
• Proerythroblasts differentiate to:
•
•
•
•
basophilic erythroblast,
polychromatophilic and
orthochromic normoblasts.
The nucleus is finally extruded from the
normoblast.
See: Erythrocytes of frog,
• Nucleated
• Primitive!
• In human –
only during
formation, in
bone marrow normoblasts
Reticulocyte
• young erythrocytes
still contain some
organelles,
• … may enter
circulation
• … remain for a few
days in the bone
marrow to mature to
erythrocytes
Reticulocyte
Erythrocyte
is leaving
RBM
Granulocytes
• Myeloblasts proliferate to generate
promyelocytes.
• Promyelocytes begin to accumulate nonspecific
granules, but they are still able to divide. The
maturation of their progeny,
• … the Myelocytes, young leucocytes, are
characterised by the accumulation of specific
granules and changes in nuclear morphology.
• Metamyelocytes have C-shaped nucleus.
Blood Platelets (Thrombocytes)
• Are formed from giant myeloid cells called
megakaryocytes (60 to 160 µm in
diameter).
• Cytoplasmic processes of these cells
extend into marrow sinuses and fragment
away. These cellular fragments are the
platelets or thrombocytes.
• Megakaryocytes are
in turn the product of
the differentiation of
basophilic
megakaryoblasts.