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Erythrocytes aka RBC

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Erythrocytes aka RBC s Laboratory Procedures Acanthocytes (Spur Cells) The term acanthocyte is derived from the Greek word acanthi meaning thorn ... – PowerPoint PPT presentation

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Title: Erythrocytes aka RBC


1
Erythrocytes aka RBCs
  • Laboratory Procedures

2
What is Blood?
  • Whole Blood fluid and cells
  • Fluid Component PLASMA
  • Cellular Component
  • Erythrocytes (RBC)
  • Leukocytes (WBC)
  • Thrombocytes (Platelets)

3
How Are These Cells Produced?
  • Hematopoesis the production of blood cells and
    platelets.
  • Erythropoesis the production of erythrocytes
    (RBC)
  • In juveniles, blood produced in liver, spleen,
    thymus and bone marrow.
  • In adults, primary site of erythropoesis is in
    the bone marrow.
  • During times of hematopoetic stress, the slpeen
    and liver may produce RBC

4
Leukopoiesis the production of leukocytes or
WBC Thrombopoiesis the production of
thrombocytes or platelets
5
All of these cells come from ONE CELL!!
STEM CELL
Proteins called Cytokines are responsible in
determining the fate of all stem cells.
6
These cytokines determine in the cell will be
either Myeloid Erythroblasts Erythrocytes
(Erythropoietin) Megakaryocytes
Platelets Myeloblasts Leukocytes / Monocytes
7
Cellular Maturation Diagram
8
Blood Composition
  • Separates into three components
  • Red Blood Cells (RBCs)
  • White Blood Cells and platelets (buffy coat)
  • Plasma
  • Bottom 1/3 to ½ of tube contains the heaviest of
    cellular material (the RBCs).

9
HematocritPCV (Packed Cell Volume)
  • To determine hematocrit, whole blood is
    centrifuged to pellet the red blood cells.
  • Plasma remains on the top of the red cells.
  • The fraction of blood that is packed is the
    hematocrit and is read as a percentage.

10
Hemoglobin (Hgb)
  • Normal values are usually 1/3 of the hematocrit.
  • Each hemoglobin molecule has 4 heme units
    attached to globulins.
  • Abnormal heme groups, cannot carry oxygen.
  • Carboxyhemaglobin- Hgb has a higher affinity for
    CO than O2.
  • Bright red blood
  • Methemoglobin- The Fe molecule is oxidized to
    Fe3.
  • Blood becomes brown.
  • Tylenol toxicity in cats.

11
Hemoglobin Molecule
12
Red Blood Cells
  • Function
  • Carry oxygen to the tissues
  • Oxygen must be carried at enough pressure to
    permit rapid diffusion of oxygen.
  • The RBC is a vehicle for hemoglobin which is the
    carrier molecule for oxygen.
  • The sigmoid shape of curve is a result of the
    cooperative binding from the 4 hemoglobin
    molecules.

13
Erythrocytes
The morphological features of mature red blood
cells of dogs, cats, horses, and ruminants are
generally very similar in that they all lack
nuclei, stain reddish to reddish-orange.
Erythrocytes are biconcave discoid-shaped
cells.
14
The major differences are in the size of the red
blood cells and the degree of central
pallor. Listed from largest to smallest in size
are Dog Cat Horse Cow Sheep Goat
15
Erythrocytes
  • Maturation of a RBC.
  • Only occurs in the bone marrow of normal adult
    animals.
  • Occurs in the spleen and liver of the fetus.
  • Maturation time usually takes 5 days.
  • Regulated by erythropoietin (EPO) which is
    increased in the presence of hypoxia.
  • In most species, the kidney is the sensor organ
    and major site of EPO.

16
Red Blood Cells (Erythrocytes)
  • No nucleus due to have to fold and squeeze
    through tight spaces.
  • Normocytes- cells look normal

17
Erythrocyte Life Span
  • Dog- 110 days
  • Cat- 70 days
  • Cow- 160 days
  • Horse- 145 days
  • Man- 120 days
  • Mouse- 30 days

18
Erythrocyte Life Span
  • Stem Cell ? Rubriblast ? Prorubricyte ?
    Metarubricyte ? Rubricyte ? Reticulocyte ? RBC
  • Rubricyte- nucleated RBC releases in severe
    anemia.
  • No more mitotic division takes place after this
    stage.
  • .

19
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20
Normal Erythrocytes
  • Morphologic features vary from species to species
  • Dogs Biconcave disk shape with central pallor
  • Cats Generally round with little central
    pallor.
  • Birds Contain a nucleated RBC

21
Categories of Erythrocyte Characteristics
  • 1. Cell arrangement on the blood film.
  • 2. Size
  • 3. Color
  • 4. Shape.
  • 5. Presence of structures on erythrocytes

22
Cell Arrangement on Blood Film
  • Rouleaux
  • Rouleaux formation is a group of erythrocytes in
    stacks. This can be a sign of increased
    fibrinogen or globulin concentration secondary to
    inflammation.
  • It can also be an artifact seen in blood that is
    held too long before preparing the blood slide or
    in blood that has been refrigerated.

Can be a normal occurence!!
Most Commonly Seen in Horses!!!
23
Cell Arrangement Continued
  • Agglutination
  • Agglutination, which appears as rouleaux, occurs
    in immune-mediated disorders. An antibody coats
    the cell causing bridging or clumping.
  • If you add a drop of saline to a drop of blood
    rouleaux formation will disperse and
    agglutination will not

24
Size
  • Terms
  • Anisocytosis
  • Variations in size
  • Can indicate anemia
  • Macrocytosis
  • Larger than normal cell size
  • Liver disease or Vitamin B12 deficiency
  • Microcytosis
  • Smaller than normal cell size
  • Iron deficiency

25
MCV
  • Mean Corpuscular Volume
  • Describes cells as normocytic, microcytic, or
    macrocytic. Calculates the average volume of
    rbcs.
  • MCV(Hematocrit x 10)/RBC count in millions
  • Normal 66-77

26
Color
  • Polychromasia (polychromatophilic)
  • Polychromatic erythrocytes exhibit a bluish tint.
    The tint is due to a small amount nucleus
    retained in the cytoplasm. These are young cells
    and may appear as a reticulocyte
  • Hypochromasia
  • is a decrease in color, due to a decreased
    staining intensity caused by insufficient
    hemoglobin within the cell.
  • Iron deficiency is the most common cause.
  • Hyperchromasia (hyperchromatophilic)
  • refers to cell that appears darker than normal
    cells. This gives the appearance that the cell
    is over saturated with hemoglobin. The
    erythrocyte has a fixed maximum capacity for
    hemoglobin and over saturation can NOT occur.

27
MCHC
  • Mean Corpuscular Hemoglobin Concentration
  • describes cells as normochromatic or
    hypochromatic.
  • MCHC (Hgb)/(Hct) x 100
  • Normal is 31-36
  • (we will come back to this calculation again)

28
Polychromasia
29
Hypochromasia
Usually associated with iron deficiency. Especiall
y in Llamas
30
Hypochromasia continued
  • Hypochromatic should be differentiated from cells
    with the center punched out. A punched out
    appearance can be an artifact due to improper
    smear technique

31
Hyperchroasia
32
Shape
  • Poikilocytosis
  • Poikilocytosis is a major deviation in the normal
    shape of the erythrocyte. The term
    poikilocytosis is an umbrella term that is used
    for any and all abnormally shaped erythrocytes
    and does not suggest a specific diagnosis

33
Schistocytes (Fragmented Cells)
  • Also known as poikilocytes.
  • RBCs with abnormal shape.
  • Formed as a result of shearing of the cell by
    fibrin strands. This occurs when red blood cells
    rapidly pass through microvasculature that is
    lined or meshed with strands.
  • They are observed in fragmentation hemolysis
    caused by DIC, vascular neoplasia, endocarditis,
    and possibly iron deficiency anemia.

34
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35
Acanthocytes (Spur Cells)
  • The term acanthocyte is derived from the Greek
    word acanthi meaning thorn Acanthocytes are
    cells with five to ten irregular, blunt,
    finger-like projections.
  • The projections with vary in width, length and
    surface distribution. These cells are seen in
    animals with altered lipid metabolism such as
    cats with hepatic lipidosis or dogs with liver
    disease.

36
Acanthocytes Continued
37
Echinoctyes (Burr Cell)
  • Echinocytes have multiple, small, delicate
    regular shaped spines evenly distributed around
    the cell and are indistinguishable from
    artificially crenated cells.

38
Echinoctyes Continued
  • Echinocyte formation can be artificial, often
    seen with slow drying blood films or if the EDTA
    tube was underfilled. This artifact is then
    termed crenation.
  • Echinocytes have been associated with renal
    disease, lymphosarcoma and rattlesnake bites in
    dogs.
  • They can be seen after exercise in horses.

39
Crenation
  • Identified as the presence of many irregular
    membrane projections involving most RBCs.
  • It is usually an artifact due to slow drying of
    the blood film.
  • Commonly observed in pig blood but can be seen in
    any species.

40
Drepanocytes (Sickle cell)
  • These cells are crescent shaped with pointed
    ends.
  • Drepanocytes are often seen in normal blood of
    deer and goats. It is thought to be a result of
    low oxygen tension.

41
Drepanocyte contd
42
Keratocyte (Helmet/Blister Cells)
  • Also called blister cells or bite cells.
    Keratocytes are associated with trauma especially
    cellular damage from contact with fibrin strands.

43
Prekeratocytes
  • Cells with pseudovacuoles are called blister
    cells or pre-keratocytes.

44
Spherocytes
  • Cells have a spheroid shape instead of the usual
    biconcave disk shape.
  • Have reduced cell membrane and are hypochromatic.
  • Seen most frequently in autoimmune hemolytic
    anemia (AIHA). When WBC partially remove
    antibody-coated membranes.
  • Usually seen in dogs.

45
Stomatocytes
  • The appearance of stomatocytes with their oval or
    rectangular central pallor has been compared to
    a smiling face, a fish mouth, and a coin slot.
  • Stomatocytes are associated with an hereditary
    condition but are also seen in liver disease,
    acute alcoholism (humans), and electrolyte
    imbalances.

46
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47
Anulocytes
  • These are bowl shaped erythrocytes that form as a
    loss of membrane flexibility that does not allow
    the cell to return to a normal shape after
    passing through a capillary. They can occur due
    to lowed hemoglobin concentration or as an
    artifact.

48
Dacryocytes (tear drop cells)
  • These tear drop shaped cells are seen in
    myeloproliferative diseases. These cells can be
    produced as an artifact but can be identified by
    the direction of their tail

49
  • Dacryocytes produced as an artifact have their
    tails pointing in the same direction.

50
Target Cells and Folded Cells aka Codocytes
  • Two types of cells observed mainly in dogs.
  • Represent cells with an outfolding of the rbc
    membrane.
  • The cell membrane is thin and flimsy.
  • Can be associated with liver dz and
    reticulocytosis.

51
Target Cells (Mexican Hat Cells)
  • Also called codocytes
  • Thin, bell-shaped cells
  • Centrally stained area
  • May be seen as
  • artifacts when smears
  • made in high humidity
  • or if blown dry.
  • Can indicate liver disease or hemoglobinopathies.

52
Target Cells
53
Howell-Jolly Bodies
  • Nuclear remnants observed in young erythrocytes.
  • Often observed in cats and horses.
  • Can be seen in regenerative anemic animals.
  • Also may be seen with splenic disease or in an
    animal with the spleen removed.

54
Nucleated Red Blood Cells (NRBCs)
  • Nucleated red blood cells (NRBC) usually
    represent early release of immature red blood
    cells during anemia.
  • These are nuclear remnants seen in young
    erythrocytes during a response to anemia.

55
Nucleated Erythrocytes
  • Metarubricytes are sometimes found in the
    peripheral blood.
  • Usually observed with regenerative anemias.
  • May be found in non-regenerative states such as
    lead poisoning and hypoxia.

56
Basophilic Stippling
  • Observed in RBCs that contain abnormal
    aggregation of RNA.
  • Can be observed in cases of heavy metal poisoning
    with non-regenerative anemias or intense
    erythrogenesis in dogs, cats, and ruminants.

57
Heinz Bodies
  • Particles of denature hemoglobin protien.
  • They stain with new methylene blue and appear as
    colorless bumps with quick stain.
  • May be caused by oxidant drugs and chemicals.
  • Normal cat blood may have 2-3.
  • Spleen recognizes as abnormal and starts to lyse
    the cells.

58
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59
Reticulocytes
  • These are immature red blood cells that contain
    organelles (ribosomes) that are lost in the
    mature cell. Cats have two forms of
    reticulocytes.
  • The aggregate form contains large clumps of
    reticulum.
  • The punctate form, unique to cats, contains two
    to eight singular granules

60
Reticulocytes in the Peripheral Blood
  • Non-nucleated cell containing RNA which can be
    easily seen when stained with methylene blue.
  • Hallmark of erythrocyte regenerative response.
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