Test on Hematology Flashcards
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What type of tissue is blood?
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connective
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What are the three main functions of blood?
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transportation, regulation, protection
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What are the protection factors of blood?
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WBCs and clotting factor
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What hormone in males stimulates erythropoesis? (this explains why males have a higher hematocrit than females)
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testosterone
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What is not included in the formed elements of blood?
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plasma
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What is contained in the buffy coat?
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WBCs and platelets
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What is the hematocrit?
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% of total blood volume occupied by RBCs
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The following does what to the buffy coat layer: infection, inflammation, dehydration, cancer, leukemia?
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increases buffy coat layer
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Where do microfilaria occur in centrifuge tube of blood?
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above buffy coat
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What constitutes plasma?
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mostly water, but also plasma proteins
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What is the function of plasma proteins?
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maintain water balance between intra- and extracellular fluid components via oncotic pressure
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Where are plasma proteins derived from?
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liver (most) and WBCs
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What plasma proteins are derived from WBCs?
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gamma globulins
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What plasma protein transports lipids?
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albumins
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What plasma protein is involved with clotting?
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fibrinogen
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As plasma protein concentration is relatively stable, what is the usual concentration in 100ml of fluid?
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7g
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During inflammation or an animal bleeding, what happens to PCV and [PP]?
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PCV is normal (slightly reduced because of increased protein and same volume of blood) and PP is increased (because trying to make more clotting factors)
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If an animal is dehydrated, what happens to the PCV and [PP]?
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Both increased (because there is less water available and therefore concentrations of both increase)
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In what instance will [PP] be decreased?
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end-stage liver disease (because liver no longer producing plasma proteins)
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All formed blood elements originate from what?
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pluri-potent stem cells
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What are the two stem lines produced by pluripotent stem cells?
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myeloid and lymphoid
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What do myeloid stem cells differentiate into?
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RBCs, platelets, monocytes, granulocytes
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What do lymphoid stem cells differentiate into?
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B and T lymphocytes
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Where are the major sites of erythropoesis in adults?
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flat bones
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Where does hemopoeisis occur in fetuses?
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spleen, liver, thymus, yolk sac, lymph nodes, red bone marrow, lymphoid tissue
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Where does hemopoeisis of adults occur?
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red bone marrow and lymphoid tissue
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What is the significance of CSFs (colony stimulating factors)?
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Promote hemopoeisis
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What is hemopoeisis?
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blood cell replacement (not just RBCs)
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Where is erythropoietin formed?
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kidney
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Where is thrombopoietin formed?
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liver
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What general percentage of body weight is used to determine the volume of blood in an animal?
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7%
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True or False: Cats have a higher than normal blood volume and dogs have a lower than normal.
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False (switched)
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What type of horse has a higher than normal blood volume compared to average?
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warm-blooded horses
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What is the volume of blood in a cold-blooded stallion weighing 700kg?
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49L (700kg x 7/100 = 49 L)
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How much blood can safely be withdrawn from a patient? Healthy donor?
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1% BW; 2% BW
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When performing fluid replacement therapy, how much can safely be infused into severely dehydrated animal?
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7% BW over an hour (next 24 hours, infuse another 7%)
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What is erythron?
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RBCs and precursors
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What are circulating corpuscles which contain oxygen carrying hemoglobin?
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erythrocytes
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What is the main function of RBCs?
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gas exchange
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What are characteristics of RBCs that are measured in mammals to determine healthiness?
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shape, size, concentration, content, metabolism
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A nearly saturated solution of hemoglobin = what percentage of RBC?
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33%
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Compared to mammal RBCs, what is different about reptiles/amphibians/birds RBCs?
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nucleated, larger, oval, non-functional mitochondria
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What is different about camelid RBCs?
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oval in shape
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What is the normal shape of mammal RBCs?
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round
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Where are RBCs produced in bony fish?
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spleen and liver
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Where are RBCs produced in cartilaginous fish?
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within circulation
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What animal has no RBCs at all?!
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Antarctic Icefish
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What is significant about the repair process of RBCs?
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does not exist
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How long do RBCs survive on average?
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4-5 months
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In health and throughout every day life, approximately what percentage of RBCs die/are removed and have to be replaced?
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1%
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For RBCs with a shorter lifespan, what changes about the percentage of RBCs that die and are replaced per day?
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increases
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What causes damaged RBCs to be recognized as foreign bodies?
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antigenic groups
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Where do damaged RBCs most often rupture (what organ)?
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spleen
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Where is present in the spleen that allows RBCs to be recycled and absolved?
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macrophages
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What system allows the selective removal of damaged RBCs in spleen, liver, bone marrow?
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mononuclear-phagocytic system
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What is the recycled globin from RBCs used for?
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protein synthesis
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What (after iron removal) is converted to bilirubin by macrophages during RBC breakdown?
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protoporphyrin
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What happens to iron after recycling by macrophages performing RBC breakdown?
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binds to plasma protein to form transferrin
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What binds with erythroblastic receptors to release iron into blast cells for hemoglobin synthesis?
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transferrin
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When iron is released into the liver, it binds to an intracellular protein to form what?
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ferritin
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What is the iron-transport form?
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transferrin
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What is the iron-storage form?
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ferritin
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What happens if ferritin stores are full?
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stored as hemosiderin in liver, pancreas, heart, can lead to toxic liver damage
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What is the disease associated with hemosiderin (nearly insoluble)?
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hemosiderosis (iron-storage disease in birds/reptiles)
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What birds suffer most often from iron-storage disease (especially in captivity)?
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toucans
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Can an animal recover from hemosiderosis?
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Not usually (can bleed animal to help)
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What controls erythropoeisis?
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tissue oxygenation
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What are immature RBCs?
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reticulocytes
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What are the precursors of reticulocytes?
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rubriblast
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How long does it take to get from stem cell to reticulocyte?
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4-5 days
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How long does it take for a reticulocyte to mature into a erythrocyte?
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1-2 days
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What is the normal reticulocyte count in blood?
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1-2%
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In what animals are there no reticulocytes when healthy?
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horses and ruminants
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Erythropoeisis requires adequate supplies of what?
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iron, folic acid, Vit B (2,6,12)
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Can a reticulocyte make hemoglobin?
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No (happens when maturing before this stage)
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What are ways to strongly stimulate erythropoeisis?
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blood loss, increased elevation
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When erythropoeisis is strongly stimulated, what happens to the number of reticulocytes? What is this called?
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increases; reticulocytosis
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In dogs, what is the percentage of reticulocytes during reticulocytosis?
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25%
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Full replacement of RBCs after a challenge takes approximately how many days?
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14
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Which are larger: RBC or reticulocyte? Why?
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reticulocyte because it contains remnants of nucleus
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In extreme cases of blood loss and reticulocytosis, what can be seen in blood and can turn the buffy coat pink?
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RBC precursors (metarubricytes, rubricytes, rubriblasts)
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Can immature precursos of RBCs participate in oxygen-carrying?
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Yes (still making hemoglobin, but there is enough to carry and deliver oxygen!)
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True or False: horses do not show reticulocytosis.
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true
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True or false: ruminants show mild responses of reticulocytosis.
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true
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What kind of reticulocytes are we looking for in a blood smear (especially in cats)?
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aggregate (lots of granules)
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What are the three parameters measured with erythron evaluation?
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hematocrit, RBC count, hemoglobin content
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How do you determine Hb content?
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by color (darker=more, lighter=less)
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What is the difference between hematocrit and RBC count?
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hematocrit is % of RBCs present in whole blood; RBC count is number of RBCs in whole blood
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What is the general value of Hb content?
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12-15g Hb/dL blood
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What three primary values are used to calculate RBC parameters?
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hematocrit, RBC count, Hb content
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What describes the volume of one erythrocyte?
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MCV (mean corpuscular volume in femtoliter)
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What describes the hemoglobin content in a deciliter of RBCs?
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MCHC (mean corpuscular hemoglobin concentration in %)
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What can cause a microcytic evaluation of MCV?
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iron deficiency
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What is a normal MCV called?
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normocytic
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What is a smaller than normal MCV called?
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microcytic
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What is a larger than normal MCV called?
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macrocytic
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What causes macroctic evaluations of MCV?
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immature RBC presence
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What is a normal MCHC called?
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normochromic
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What is a low MCHC called?
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hypochromic
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What is a high MCHC called?
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hyperchromic
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What is a normochromic MCHC value?
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33%
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What can cause hypochromic MCHCs?
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iron deficiency, immature RBCs
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What can cause hyperchromic MCHCs?
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hemolytic sample
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What is the deficiency of oxygen carrying capacity?
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anemia
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What are the classifications of anemia based on causes?
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hemorrhagic, hemolytic, dsyhemopoeitic
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Extensive blood loss is what type of anemia?
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hemorrhagic
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Ruptured RBCs is what type of anemia?
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hemolytic
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Malfunction with the production of RBCs is what type of anemia?
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dyshemopoeitic
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What are the classifications of anemia based on bone marrow response?
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regenerative, non-regenerative
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What type of anemia involves the animal compensating for deficiency by producing more RBCs?
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regenerative
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What type of anemia involves the animal having normocytic and normochromic evaluations?
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non-regenerative
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How can you determine if an animal is in regenerative anemia?
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RBCs will be different sizes
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If an animal suffers from acute blood loss, what hormones come into effect in the kidney?
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aldosterone and ADH
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How long does it take for the body to replace fluids lost in a hemorrhagic anemia?
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2 days
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Directly after hemorrhage, what will PCV and [PP] show?
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normal results
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A few days after hemorrhage, what will PCV, [PP], MCV, MCHC, and Hb content show?
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decreased PCV, Hb content, and [PP] MCV and MCHC will be normal
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After a hemorrhage, when does erythropoeisis begin?
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immediately after accident
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After a hemorrhage, how long does it take for the MCV to show macrocytic values? Why?
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~3 days; takes that long for precursors to mature into reticulocytes
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What are the parameters in hemolytic anemia?
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normocytic, hyperchromic, regenerative
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What type of anemia involves something being wrong at the level of hemopoeisis?
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dyshemopoeitic anemia
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In dyshemopoeitic anemia due to nutritional deficiencies where cells cannot produce enough Hb and keep on dividing, what are the parameters?
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non-regenerative, microcytic, hypochromic
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What is the most common type of dyshemopoeitic anemia?
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anemia of chronic disorders
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What are the parameters for dyshemopoeitic anemia due to chronic disorders like cancer?
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normocytic, normochromic, non-regenerative
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True or False: Hemorrhagic and hemolytic anemias can become chronic disorders and lead to exhaustion of iron stores after long stimulation and eventually become non-regenerative anemias.
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True
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What is polycythemia?
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increase in RBC numbers
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Primary polycythemia is a rare disorder. What is it and it what animals is it normal in?
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uncontrolled RBC production; normal in sight hounds
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What is secondary polycythemia?
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increase in RBC numbers due to oxygen deficiency from underlying cause (cancer, high altitudes, lung disease)
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What is transient polycythemia and it what animals is it seen in?
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Spleen contraction due to excitement and exercise which releases more mature RBCs and increases PCV; seen in horses, cats, sight hounds
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What is not a true polycythemia, but is caused by dehydration and therefore all blood components become more concentrated?
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relative polycythemia
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Do animals have blood groups?
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yes
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What kind of blood system is present in cats?
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A - B system
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In North America, almost 99% DSH cats are what blood type?
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A
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In Europe, what percentage of DSH cats are type A?
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50%
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In purebred cats like the persian, what is the blood type ratio?
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1:1 (50% A and 50% B)
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What are the highly antigenic blood types in dogs?
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1.1, 1.2, 7
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What animals carry natural antibodies in their blood circulating? What significance is this?
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humans and cats; react very quickly to wrong blood type
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How can giving the wrong blood type to a cat lead to acute renal failure?
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agglutination of invading RBCs, blockage of capillaries, shcok, precipitation of excess Hb after rupture of RBCs, renal blockage, renal failure
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If a dog is given the wrong blood type for the first time, what happens? Second time?
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mild, delayed reaction; full blown immune response
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What is the determination of the RBC antigens present in an individual?
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blood typing
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What is the ideal donor dog?
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one without antigens 1.1, 1.2, and 7
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When cross-matching blood, how can you determine if there will be a major reaction?
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expose donor's RBCs to recipient's plasma and observe for agglutition
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When cross-matching blood, how can you determine if there will be a minor reaction?
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expose recipient's RBCs to donor's plasma and observe for agglutition
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If there is a minor reaction when cross matching blood types, what can be done to allow the blood to be used to avoid a minor reaction?
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remove plasma and replace with saline
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What is hemostasis?
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sequence of responses that stops bleeding
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What are three ways to describe hemostasis?
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fast, localized, carefully controlled
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What are the five steps of hemostasis?
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vascular spasm, platelet plug formation (primary hemostasis), blood clot formation (secondary hemostasis), healing, clot removal (fibrinolysis)
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What is primary hemostasis?
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platelet plug formation
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What is secondary hemostasis?
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blood clot formation
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What is fibrinolysis?
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clot removal
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What is the shape of platelets?
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flat, round to oval, enucleate
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What is different about the platelets of birds and reptiles compared to mammals?
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nucleated
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What is different about the size of platelets when compared to RBCs?
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about half the size
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What is the normal concentration of platelets in a microliter of blood?
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150,000-300,000 platelets per microliter
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What is the half-life of platelets?
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10 days
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Where are platelets derived from?
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bone marrow megacaryocytes (pluripotent -> myeloid -> CFU ->megakaryoblast -> megakaryocyte ->platelets)
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What stimulates the production of platelets and is produced by the liver?
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thrombopoietin
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What are the functions of platelets (four)?
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release of chemicals that promote vasospasm, formation of platelet plugs, release of factors that promote coagulation, healing processes
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When does vasospasm occur after vessel injury?
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immediately
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What causes vasospasm immediately after vessel injury?
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endothelin release from damaged cells
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What causes vasospasm later after vessel injury?
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thromboxane A2 and serotonin from platelets
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What is primary hemostasis?
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platelet plug formation
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What is released by damaged endothelial cells?
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vWF (von Willebrand Factor)
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When endothelial and plasma vWF bind to damaged cell membranes and collagen fibers, what binds to the now expressed receptor sites?
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platelets
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What happens when platelets bind to receptor sites at areas of damaged tissues?
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send out pseudopodia to interact with other platelets
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What do platelets release once bound to receptor sites of damaged tissue to stimulate vasospasm?
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serotonin and thromboxane a2
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What is released from platelets to attract more?
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ADP and thromboxane a2
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What is released from platelets to promote adhesion?
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ADP and fibronectin
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For clotting to happen, what mineral must be present along with platelet factors?
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calcium
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For a minor injury, how long does it take for a loose platelet plug to seal injury site?
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1-2 minutes
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With larger injuries, the clotting cascade is activated concurrently to stabilize the platelet plug with what?
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fibrin strands
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What is secondary hemostasis?
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clot formation (coagulation)
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Clot formation involves cascades of chemical reactions leading to the formation of strong ___ threads within the platelet plug, which gives it more strength.
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fibrin
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What are the two pathways which lead to the formation of a prothrombin-activator complex?
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extrinsic and intrinsic
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What converts fibrinogen to fibrin?
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thrombin
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What converts prothrombin to thrombin?
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prothrombin-activator complex
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Which of the coagulation pathways is tissue based?
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extrinsic
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Which of the coagulation pathways is plasma based?
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intrinsic
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In the intrinsic pathway, what activates plasma factor XII which leads to the formation of the prothrombin activator complex?
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negative charges on outside of cell
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Which coagulation pathway is faster?
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extrinsic
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Which coagulation pathway is not present in birds?
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intrinsic
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What is a plasma protein from the liver that is from the globulin family and attaches itself to activated platelets to form the prothrombin activator complex?
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prothrombin
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What is the cofactor of prothrombin?
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vit K
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What encourages the intrinsic/extrinsic pathways of blood coagulation and stimulates fibrin formation?
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thrombin
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How long after injury does it take for bleeding to be stopped by coagulation?
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3-6 minutes
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How long does it take for the clot to retract from a minor injury?
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30 minutes
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The blood fluid that remains after hemostasis is called what?
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serum
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Serum is plasma minus what?
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clotting factors
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Fibrin provides scaffolding for what cells to promote wound healing?
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fibroblasts
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What are fibroblasts stimulated by?
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platelet derived endothelial growth factor
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What is fibrinolysis?
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clot removal
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1-2 days after clot formation, what does the injured tissue and endothelium release very slowly which activates a proteolytic enzyme meant to denature the clot?
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t-PA (tissue-plasminogen activator)
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What does t-PA do?
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changes plasminogen to plasmin
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What does plasmin do?
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hydrolyses fibrin fibers and clotting factors
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What is created by plasmin?
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FDPs (fibrin degradation products)
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What removes FDPs?
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macrophages
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What factors prevent unnecessary hemostasis?
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smoothness of endothelial cells, prostacyclin (secreted by endothelial cells) and Nitric Oxide which inhibit adhesion
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What prevents excessive clot formation?
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fibrin binds thrombin to limit positive feedback, anti-thrombin III deactivates clotting factors, heparin from amst cells combins with anti-thrombin III to augment effectiveness.
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What is used for in vitro anticoagulation?
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calcium binding agents, heparin
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What is used for in vivo anticoagulation?
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heparin, vit K antagonists, NSAIDs
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Why is it important that calcium binding agents are used for anticoagulants?
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Because prevents calcium from binding to platelet factors to avoid coagulation
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Can we use calcium binding agents in vivo?
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NO - fatal to animal to remove calcium from body
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Why can we use Vitamin K antagonists in vivo as anticoagulants?
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Cofactor of prothrombin, prevents coagulation
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If a dog is suspected to have a bleeding disorder, what can be used to determine whether issue is initially with platelets?
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platelet count
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How do you test whether issue is with von Willebrand factor and platelets?
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Muscosal bleeding time
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What is the muscosal bleeding time test?
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Make minute incision into skin or mucosa and stop time when bleeding stops (want to be 1-5 minutes)
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What test for determining extent of bleeding disorders involves measuring clot formation in citrated plasma after addition of tissue factor, platelet factors, and calcium?
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OSPT (one stage prothrombin time)
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What does the OSPT test measure?
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extrinsic and common pathway of clotting mechanism
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What three things are necessary to add when performing the OSPT and why?
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Calcium (because citrate removed calcium), platelet factors (to rule out whether they are interferring with tests), and tissue factors (because clean venipuncture would mean none is brought into sample)
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What is the expected time of OSPT?
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<10 seconds
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IF the OSPT test is prolonged, what factors are possibly messed up?
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plasma factors, fibrinogen, and thrombin
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What test involves measuring clot formation after clean venipuncture in citrated plasma and addition of contact activator, platelet factors, and calcium?
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APTT (activated partial thromboplastin time)
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If OSPT = prolonged, APTT = normal, where is issue?
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extrinsic pathway plasma factors
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If APTT = prolonged, OSPT = normal, where is issue?
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intrinsic pathway plasma factors
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If APTT and OSPT = normal, where is issue?
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common pathway (fibrinogen and thrombin)
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What is thrombocytopenia?
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decreased production or increased destruction or consumption of thrombin
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What are coagulopathies?
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bleeding disorders
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What is the most common bleeding disorder in animals due to genetic lack/insufficiency in vWF where platelets fail to adhere to injury sites?
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von Willebrand's Disease
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What breed of dog most often has von Willebrand Disease with 70% prevalence?
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Dobermans
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What is a vitamin K antagonist in rat poisons which impairs liver synthesis of several clotting factors?
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coumarin
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What are genetic deficiencies in a clotting factor?
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hemophilias
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What is clotting in an unbroken blood vessel (due to stasis, atherosclerosis, trauma, parasites, tumors, etc)?
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thrombosis
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What thrombosis in cats is due to myocardial diseases where clot becomes lodged at caudal trifurcation where aorta diverges into iliac arteries?
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saddle thrombus (aortic thromboembolism)
