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253 Cards in this Set
- Front
- Back
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HEMATOPOIESIS
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There are three types of cellular elements in the blood:
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Platelets are actually cell fragments – do not contain a true nucleus.
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Each of these cellular elements has its own function, differs morphologically from each other and has its own life span
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What are the three types of cellular elements in the blood?
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Leukocytes – WBCs
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Thrombocytes – platelets
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What are Pluripotent stem cells ?
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Cells that are able to develop into several cell lines
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Hematopoietic cells
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Derived from pluri potent stem cells the y divide and differentiate into different progenitor cells for each cell line
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Also, what does it function to do?
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These tissues and organs are involved in the production, maturation, and destruction of blood cells.
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Origin of Hematopoiesis: Embryo
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Yolk sac then liver
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Origin of Hematopoiesis: 3-7 months
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spleen
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Origin of Hematopoiesis: 4-5 months
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Marrow cavity especially granulocytes and platelets
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Origin of Hematopoiesis 7 months
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marrow cavity- erythrocytes
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Origin of Hematopoiesis birth
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mostly the bone marrow spleen and liver when neeeded
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Origin of Hematopoiesis adult
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Bone marrow of skull ribs sternum vertebral column and proximal ends of femur
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Number of red blood cells are affected by
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Changeds in plasma volume
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Erythropoietin is scretid by the __1___ in response to ___2__that is detected by the cells of the ____1____ it stimulates the ___3___(substance in a structure) to produce rbc’s
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1)KIDNEY
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Erythropoisis can be also incouraged by these systems:
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WHAT ARE THE COMMON CELL STRUCTURES?
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Plasma membrane
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Size: 4 to 20 mm in diameter
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Cytoplasm:
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Relatively small amount
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May have perinuclear halo
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Nongranular
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Nucleus: Relatively large, round
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Has visible nucleoli (1-2) and indistinct chromatin strands
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Stains reddish blue or reddish purple
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N/C ratio 8:1
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It is very hard to distinguish the rubriblast from the myeloblast. The rubriblast is usually slightly larger than the myeloblast, and has more cytoplasm that stains a deeper blue.
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Size:
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Cytoplasm: Intensely blue
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as it is accumulating more RNA but may have a pinkish tinge reflecting the amount of Hb present
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Non-granular
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Nucleus: Relatively large
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N/C ratio 6:1
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Chromatin pattern starts to coarsen
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If present, nucleoli usually are not visible.
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This cell is slightly smaller than the rubriblast.
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Size:
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Cytoplasm:
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More cytoplasm than previous stage
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Stains blue gray to pink gray due to increase in Hb production. Late stages, pink-gray is the predominant color.
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Nucleus:
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Non-granular chromatin is thickened and irregularly condensed.
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Parachromatin is visible.
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N/C ratio is 4:1
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Nucleoli are no longer visible.
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Size:
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Cytoplasm:
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Predominantly pink due to increased Hb synthesis
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May still contain some amount of blue due to RNA.
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Non-granular
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Nucleus:
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N/C ratio is about 1:2
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Small pyknotic nucleus (blue-black mass with no structure)
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This stage is incapable of further DNA synthesis. This degenerated nucleus is destined to be extruded and will be phagocytized.
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Size:
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7 to 10mm in diameter – just slightly larger than mature RBC
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Cytoplasm:
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Pink to slightly pinkish gray
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Using a supravital you can see a fine basophilic reticulum of RNA.
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Nucleus:
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none present
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A reticulocyte is released in 2 to 3 days from the marrow and circulates for 1 or 2 days before maturing into an erythrocyte
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Reticucyte in new methyl blue stain
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Size:
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6 to 8 mm
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Cytoplasm:
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Pink in color
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Nucleus:
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These are biconcave disks.
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ABNORMAL HEMOGLOBINS
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RED BLOOD CELL MORPHOLOGY
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Average diameter of the RBC is 6-8 mm
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Average volume (MCV) is 90 fL. (10-15).
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Normal human MCV is 80 – 100 fL.
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The area of central pallor is approx. 2-3mm in diameter.
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Normal RBC is about the same size as a small lymphocyte.
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When inspecting a blood smear for abnormal morphology 2 criteria must be met:
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Is the abnormal morphology seen in every field to be examined?
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Is the morphology pathologic and not artificially induced?
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If these criteria are met, then the reviewer must make an assessment of anisocytosis and poikilocytosis.
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Variation in the size of RBCs (from the normal RBC).
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In scanning a peripheral smear, a reviewer takes into account the percentage of cells that vary in size in at least 10 oil immersion fields.
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variation from the normal RBC shape
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Normal = 5% of cells differ in size or shape from normal RBC
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In humans may be defined as cells approximately 9 mm or larger in diameter, having an MCV of greater than 100 fL (normal MCV = 80-100 fL).
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Macrocytes should be evaluated for shape (oval vs. round), color (red vs. blue), pallor (if present) and the presence or absence of inclusions.
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In humans are defined as small cells having a diameter of less than 6mm and an MCV of less than 80 fL.
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When developing erythroid cells are deprived of any of the “essentials” in Hb synthesis the result is increased cellular divisions, consequently a smaller cell in peripheral blood.
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Hb synthesis involves multiple steps and microcytosis develops from (1) ineffective iron utilization, absorption, or release; and (2) decreased or defective globin synthesis.
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MCV
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Dog 60-77
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Cat 39-55
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Horse 37-58.5
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Cow 40-60fL
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Any RBC having a central area of pallor of greater then 3 mm is said to be hypochromic.
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Direct relationship between the amount of Hb deposited in the RBC and the appearance of the RBC when properly stained.
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Any irregularity in Hb synthesis will lead to some degree of hypochromia.
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Most clinicians choose to assess hypochromia based on the MCHC (mean corpuscular Hb content), which by definition measure Hb content in a given volume of RBCs (100mL).
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Not all hypochromic cells are microcytic.
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Target cells possess some degree of hypochromia and some macrocytes and normocytes can be distinctly hypochromic.
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The most common cases of hypochromia are seen in patients with iron-deficiency anemia.
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When RBCs are delivered to the peripheral circulation prematurely, their appearance in the Wright stained smear is distinctive.
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RBCs showing polychromatophilia are gray-blue in color and are usually larger than normal RBCs.
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The basophilia of the RBC is the result of residual RNA involved in Hb synthesis.
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Polychromatophilic macrocytes are actually reticulocytes; however, the reticulum cannot be seen without supravital staining.
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It is not uncommon to find a few polychromatophilic cells in a normal peripheral blood smear, since regeneration of RBCs is ongoing.
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1% of new RBCs (retics) are put into circulation daily.
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Any clinical condition in which the marrow is stimulated, particularly RBC regeneration, will produce a polychromatophilic blood picture and the reticulocyte count will increase proportionately.
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The mechanism of targeting is related to excess membrane cholesterol and phospholipid and decreased Hb.
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These are associated with liver disease, hypothyroidism, iron deficiency, and chronic disease.
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They are found in small numbers in normal blood.
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They appear smaller than the normal RBC and their Hb content seems to be relatively concentrated.
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Because there is no visible central pallor, they are easily distinguished in a peripheral smear.
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Their shape change is irreversible.
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These cells are associated with hemolytic anemia, and immune mediated diseases
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On an air-dried smear this is shown as a “slit-like” area of central pallor.
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Certain chemical agents may induce Stomatocytosis and these changes are reversible.
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Stomatocytes are more often artifical than a true manifestation of a particular disease process.
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These may be found in liver disease.
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They are usually artifacts in animals and are not clinically significant.
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This is a cell of normal or slightly reduced size possessing three to eight spicules of uneven length distributed along the edge of the cell membrane.
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The uneven projections of the acanthocyte are rather pointed. These cells are found in severe liver disease in animals.
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Fragmentation may be defined as “loss from the cell of a piece of membrane that may or may not contain hemoglobin.”
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Fragmented as it travels through the capillaries of the spleen.
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Helmet or bite cells
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Pulmonary emboli and disseminated intravascular coagulation (DIC).
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Schistocytes are the extreme form of RBC fragmentation. Whole pieces of RBC membrane appear to be missing and very bizarre RBCs are apparent. These may be seen in cases of severe burns, hemolytic uremic syndrome (E-coli), DIC, trauma, and altered vascular flow.
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Blunt spicules evenly distributed over the surface of the RBC and usually artificial due to faulty drying of the blood smear.
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Also be due to dehydration of the patient.
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Confirm by making a new smear with a fresh sample of blood.
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Burr cells (keratocytes) are RBCs with uniformly spaced, rounded spicules on their outer edges.
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These cells occur in kidney disease (uremia), severe burns, and liver disease.
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Tear Drop Cells (Dacrocytes)
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A cell with one pointed extremity in the shape of a drop.
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Seen in myelofibrosis of the bone marrow, thalassemia, and certain types of anemias.
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Normally seen in birds, Llamas.
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RBCs that contain ribosomes can potentially form stippled cells.
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These are present as many coarse or fine, purple-staining granules in the RBC.
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The granules result from aggregation of ribosomes and are found in lead poisoning and anemias with impaired Hb synthesis.
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In dogs they are seen with lead toxicity, cats these are present with normal erythrogenesis and in ruminants basophilic stippling is a sign of intense erythrogenesis.
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These are nuclear remnants containing DNA.
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They’re 1 to 2 mm in size and may appear or doubly in an eccentric position on the edge of the cell membrane.
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They are thought to develop in times of accelerated or abnormal erythropoiesis.
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These may be seen following splenectomy, and hemolytic anemias.
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Seen in certain types of anemias
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Formed as a result of denatured or precipitated Hb.
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Large inclusions that are rigid and severely distort the cell membrane.
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Not visible in Wright’s stain but may be seen with supravital staining such as crystal violet and brilliant cresyl blue.
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In cats these are called ER bodies – erythrocyte refractile bodies.
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They can be caused by toxins, oxidants, but most commonly are caused by acetaminophen.
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Cats form these more readily than other species due to the chemical properties of their Hb.
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A sick cat may have 10 to 20% of their RBCs containing nonspecific Heinz bodies.
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These are often confused with RBC inclusions.
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Compare the platelet with those in surrounding field. Also, there is generally a non-staining halo surrounding the platelet when it is positioned on top of the RBCs.
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These RBCs look like stacked coins.
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This may be due to an artifact (delay in smearing blood once the drop has been placed on slide) or may be due to the presence of high concentrations of abnormal globulins or fibrinogen.
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Normal in cats and horses.
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Found in patients who have a cold agglutinin or autoimmune hemolytic anemia (one of the most common types of anemia found in dogs).
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These RBCs are clumped rather than stacked.
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When agglutination of RBCs is seen on the smear, the sample should not be run through an automatic analyzer.
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Characterized by destruction of circulating RBCs e.g. blood parasites, chemicals, drugs and immune-mediated disorders
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RBCs become coated with antibodies, intravascular lysis
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Autoimmune
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Caused by: heartworm disease, Lymphoma, Lupus erythematosus, Drug induced immune mediated hemolysis.
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Spherocytes
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Coomb’s test- direct antiglobulin test
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Circulating oxidants act on rbc hgb
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Oxidation of globin leads to precipitation and the formation of Heinz bodies
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Ingestion of onions, acetaminophen
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Precipitates of oxidized hgb
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More common in cats than dog
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Haemobartonellosis felis
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On rbc surface as small basophilic rods or ring forms
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Primary or secondary disease
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Pg 51, 52
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Haemobartonellosis canis
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Multiple chains on the rbc surface
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pg 53
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Tick borne protozoan
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Babesia canis
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Intravascular hemolytic anemia
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Intraerythrocytic teardrop shaped organisms
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Pg 54
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Decrease in rbc life span
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Inherited in Beagles and Basenjis
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Anemia develops as age increases
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Chronic, regenerative
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pg 55
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Regenerative Anemia: Hemolytic Disease: Phosphofructokinase Deficiency
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Rare inherited only Springer Spaniels
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Microangiopathic hemolysis
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DIC, glomerulonephritis
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Heart worms, traumatic heart disease
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Schistocytes – fragmented rbcs
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Non-regenerative Anemia's
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Maturation Defect Anemias: Nuclear Defect (Megaloblastic anemia)
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Maturation Defect Anemias: Cytoplasmic Defect
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Cell line fail to mature and divide normally while cytoplasmic maturation
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Nuclear/cytoplasmic asynchrony
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Large cells, megaloblasts, irregular chromatin clumps
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Reduced DNA synthesis, decreased B12 or folate
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BM hypercellular
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Hypersegmented neutrophils
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Toy poodles normal
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Pg 57, 58
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Failure to form hgb.
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Hypercellular BM, build up of precursors
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Rbcs produced but smaller due to deficient Hgb
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Iron deficiency, Lead poisoning, B6 deficiency
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Hypochromic, microcytic
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Granulocytic Hyperplasia
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Anemias with Selective Erythroid Hyperplasia
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Anemias with generalized marrow hyperplasia
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Anemia of inflammatory disease
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Normocytic, normochromic
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Infections, immune disorders
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Pg 61
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Hypoproliferative anemias Anemias with Selective Erythroid Hyperplasia
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Reduced erythropoietin- renal disease, hypothyroidism
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Reduced oxygen demand and utilization
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Selective destruction of rbc precursors, in BM
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Pg 62
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Severe anemia, leukopenia, thrombocytopenia, pancytopenia
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Etiology:
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Toxic or immune mediated
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Myelophthisic- replacement by abnormal cells
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Infections- FeLV, ehrlichiosis
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Pg 63, 65
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