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124 Cards in this Set
- Front
- Back
Where is bone marrow primarily found?
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long and flat bones
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Name products of marrow hematopoiesis?
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-RBCs - oxygen delivery to tissues
-WBCs - host defense - Platlets - hemostasis |
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How many days from stem (rhubroblast) cell to reticulocyte release?
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5
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What happens with erythropoiesis?
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start with large blast cells; cells become smaller with maturation and divisions; increased hemoglobin
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What starts with an early rubricyte?
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hemoglobin synthesis starts
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What happens with a late rubricyte?
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- critical hemoglobin concentration is reached
- shuts off cell division -continues to mature |
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What happens with a metarubricyte?
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- nucleus is small and pyknotic
- ready to extrude nucleus |
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What happens with a reticulocyte (polychromatophilic RBC)?
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-nucleus is extruded
-contains residual RNA and organelles -released into marrow sinus (except horse) -the residual organs give it a bluish color -increases numbers indicate a response |
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Explain the process of reticulocyte release.
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-micrates through endothelial cells into venous sinuses
-matures 24 hours in blood -spleen pits the organells |
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What stain is used for reticulocyte ID?
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New methylene blue stain
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Explain the characteristics of a mature RBC.
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-no RNA
-gains full hemoglobin -loses blue grey color |
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What is the life span of a mature RBC?
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70-160 days (about 100)
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What characterizes anemia?
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-decrease in:
(1) #RBC/microL; (2) hemoglobin/dl; (3) %PCV (Hct) -RBC loss or destruction > production |
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What is the body's response to anemia?
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-anemia decreases oxygen carrying capacity
-renal hypoxia causes EPO release from cortex -EPO stimulates: erythrocyte progenitors, hemoglobin production and early marrow release -takes 2-3 days |
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What does EPO stimulate?
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erythrocyte progenitors, hemoglobin production and early marrow release
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What does anemia describe?
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a data abnormality, NOT a diagnosis or a disease
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What does the RBC indice mean: MCV
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mean corpuscular volume - used in classification of anemia
-average volume of red cells |
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What does the RBC indice mean: MCH
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mean corpuscular hemoglobin - used in classification of anemia
-mean amount of hemoglobin per cell |
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What does the RBC indice mean: MCHC
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mean corpuscular hemoglobin concentration - used in classification of anemia
-mean concentration of hemoglobin per cell |
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How is MCV measured?
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by instrument
-calculated by HCT X 10 / RBC |
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Where are the values MCV, MCH, and MCHC found?
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on CBC data sheets
-calculated using RBC, HGB, and HCT |
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If a patient is anemic and MCV is < the reference interval what is this called?
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Microcytic anemia - cells average smaller than normal
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If a patient is anemic and MCV is within the reference interval what is this called?
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Normocytic anemia - cells have average normal volume
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If a patient is anemic and MCV is > the reference interval what is this called?
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Macrocytic anemia - increased number of reticulocytes
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Give an example of a cause of microcytic anemia. Explain.
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Iron deficiency
-hemoglobin synthesis needs iron -critical (HGB) reached late rubricyte (normal) -results in extra (5th rubricyte division -smaller cells in circulation |
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Give an example of a macrocytic anemia. Explain.
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Regenerative anemia - reticulocytes present
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Which is more accurate, MCH or MCHC?
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MCHC --> mean concentration of hemoglobin/cell
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What is the difference between MCH and MCHC?
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MCH - mean AMOUNT of hemoglobin/cell
MCHC - mean concentration of hemoglobin/cell |
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What are the values of MCH, MCV, and MCHC in the case of reticulocytosis?
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-MCH is normal
-MCV is increased -MCHC is decreased |
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What is the term if MCH or MCHC is < the reference range?
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hypochromic - iron def. or less HGB/cell
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What is the term if MCH or MCHC is in the reference range?
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Normochromic
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What is the term is MCH or MCHC is > the reference range?
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hyperchromic - FAKE
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What does a hyperchromic result usually mean?
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FAKE - indicates RBC lysis (introvascular hemolysis or poor sample handling)
-can mean presence of Heinz bodies |
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How are anemias classified?
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(1) Size (MCV) --> macrocytic, normocytic or microcytic
(2) Classify as to hemoglobin (MCH, MCHC) --> hyperchromic, normochromic, hypogromic (3) reticulocyte count -->regenerative or non-regenerative |
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How many reticulocytes are normally in a canine and what type?
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1% - aggregate - all are counted
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How many reticulocytes are normally in a feline and what type?
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0.4%
-2 types: (1) aggregate (counted) (2) punctate (not counted) |
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Where are reticulocytes found in the horse?
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they are not - absent in health and in anemias because complete bone marroe maturation of RBCs in bone marrow
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What are 3 major causes of anemia?
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(1) blood loss - acute/chronic; internal/external
(2) hemolysis - inra or extra vascular (3) lack of production |
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Non-regenerative anemia is often a result of what?
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production failure - BM
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What are the most likely causes of regenerative anemia?
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Lysis>Loss
-can tell by plasma proteins |
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What happens when epinephrine is released?
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-spleen contracts
-releases HCT (80%) and platelets (1/3 of ciruclating platelets stored in spleen) |
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What happens with fluid therapy hours to days later?
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-dilutes cells and proteins --> anemia and hypoproteinemia
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How long does it take reticulocytosis to develop?
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-2-3 days
-max of 7-10 days because it takes 5 days for stem cells to develop |
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How long does it take for reticulocytosis to resolve?
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1-2 weeks
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What are signs of regeneration?
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(1) macrocytosis (increased MCV)
(2) hypochromia (decreased MCHC) (3) reticulocytosis ($) hypercellular bone marrow |
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How is metarubricytosis classified?
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appropriate (nRBCs with reticulocytosis)
or inappropriate (nRBCs without reticulocytosis) |
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What is the most common cause of iron def?
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chronic hemorrhage
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How many divisions occur when there is an iron deficiency?
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5 b/c longer to reach critical HB
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What are typical findings of an animal with chronic hemorrhage?
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-anemia (microcytic, hypochromic, less regenerative)
-panhypoproteinemia -thrombocytosis |
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If anemia is regenerative, what two types could it be?
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loss or lysis
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Blood loss can be ..
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acute/chronic
or internal/external |
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Hemolysis can be...
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intravascular or extravascular
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Non-regenerative anemia can be caused by what?
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lack of production
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What are 2 rule outs for microcytosis?
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(1) iron deficiency
(2) portosystemic shunts (asian breed dogs) |
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What are reasons for macrocytosis?
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regneration; agglutination
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What is a reason for hypochromasia?
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low iron
reticulocytosis (because less hemoglobin per cell) |
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What is a reason for hyperchromasia?
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artifact; hemolysis
Heinz Body anemia Hemolytic Anemia |
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Can intra and extravascular hemolysis occur at the same time?
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yes
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What is a normal % of RBCs that are destroyed and made at the same time?
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1%
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Where are RBCs phagocytosed by macrophage?
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-in spleen or liver - normal is 1%
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What phagocytoses RBCs and what happens after this is done?
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-macrophages
- and then lysed and digested in the phagosome |
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After RBC are lysed, what happens to hemoglobin?
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-it is digested to (1) globin and (2) heme
(1) globin--> amino acids (2) heme --> iron (recycled) and bilirubin (another tour) |
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Once bilirubin goes into the blood, it is bound to what?
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albumin as unconjugated bilirubin
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Once bilirubin goes into the blood, what happens?
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bound to albumin (unconjugated) --> goes to hepatocyte (glucuronide conjugation) --> conjugated bilirubin is excreted into the bile --> bile does to SI to help with digestion
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What is happening if you see bilirubin increased?
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hemolysis
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Why does extravascular hemolysis occur?
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-accelerated RBC phagocytosis by splenic macrophages (more common) or liver (less common); the macrophages line the sinusoids
-macrophages detect an abnormality on RBC membrane surface |
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Give an example of what type of RBCs may be phagocytosed by macrophages thus causing extravascular hemolysis.
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antibody on RBC, RBC parasite or Heinz Body
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When a RBC is phagocytosed partially, what re-forms?
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a spherocyte
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RBC phagocytosis results in what?
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RBC destruction (hemolysis_ - regenerative
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Spherocytes (partial phagocytosis) represents what?
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RBC targeting
-spherocytes are more likely to be phagocytosed |
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What are possible lab findings of hemolysis anemia?
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-hyperbilirubinemia
-moderate to marked reticulocytosis (iron is being recycled) -positive direct antiglobulin test - detects antibody -autoagglutination -abnormal RBCs on smear - hemic parasites, heinz bodies |
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What does the following test show/detect?
(1) Positive Direct Antiglobuilin Tests (Coomb's) (2) autoagglutination |
(1) detects anti-RBC antibodies and complement bound to RBC surface --> IMHA (primary or secondary)and indicated hemolytic anemia
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What does the following test show/detect?
(2) autoagglutination |
(2) Anti-RBC IgM or IgG (red cells cluster as grapes); infers hemolytic anemia (also will get increased MCV)
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In what species is rouleaux normal?
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-equine
-this must be disdinguished from autoagglutination (red cells stack like coins) |
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Why is Rouleaux abnormal in most species?
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-most species have a negatively charged surface membrane that repels other neighbors
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What is a possible cause of Rouleaux and why?
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-inflammation increases proteins in blood and coats surface nonspecifically (fibrinogen)
-this masks the negative charges and therefor no longer repels each other |
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How do you tell the difference between Autoagglutination and rouleaux?
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-dilute with saline 1:10
-wet mount, rouleaux disperses and autoagglutination remains |
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What is it called when bilirubin spills into the urine?
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bilirubinuria
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What does hyperbilirubinemia mean?
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hemolysis - pathologic
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What are signs of regeneration?
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-macrocytosis - increased MCV
-hypochromia - decreased MCHC -reticulocytosis -increased target cells -hypercellular bone marrow - erthroid hyperplasia |
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What are target cells?
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-bull's eye pattern
-occur in regenerative anemia because they have skipped a division and are therefore bigger cells with an increased surface volume |
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What type of reticulocyte count is preferred?
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absolute-->
% x RBC (millions) = reticulocyte # |
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What is normoblastemia?
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nRBCs in ciruclation (metarubricyes) - 1/100 WBC
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What is the difference between appropriate and inappropriate metarubricytosis?
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-appropriate metarubricytosis -- nRBC with lots of polychromasia (reticulocytes)
-inappropriate metarubricytosis - increased nRBC without regeneration (or even without anemia) |
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What are some causes of metarubricytosis?
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-severe hypoxia
-heavy metal toxicosis -bone fractures infiltrative bone marrow disease (leukemia) -extramedullary hematopoiesis - from spleen -heat stroke -sepsis |
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What occurs with slow onset of anemia due to chronic blood loss?
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adaptation to lowered oxygen
-increased 2,3 DPG (not cow or cat) -increased erythropoiesis |
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What does chronic blood loss cause?
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-depleted iron stores (external or internal) - GI, urinary are most common
-most common cause of iron def (esp young animals because they already have a low iron diet) |
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What type of anemia is caused by iron def?
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-microcytosis and hypochromasia
-regenerative initially and then non-regenerative eventually -increased RBC fragility - less deformable |
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Where is iron stored?
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BM, liver, spleen
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What are (4) typical findings with chronic blood loss?
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(1) anemia --> microcytic, hypochromic, regeneration, then less so
(2) panhypoproteinemia - all proteins lost with RBCs (3) thrombocytosis - reactive cytokine-mediated (4) characteristic RBC poikilocytosis -- different shapes of RBCs |
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Hyperbilirubinemia means what?
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hemolysis - pathologic
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Bilirubin that spills into the urine, bilirubinuria is normal (in small amounts) for what species?
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dogs
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What are causes of hemolysis?
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extra-vascular
-intra-vascular -overlap of the two |
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What does oxidative damage cause?
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-intravascular and extravascular hemolysis
-denatures hemoglobin -denatures hemoglobin and hemoglobin precipitates and aggregates forming heinz bodies -heinz bodies and eccentrocytes |
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What animal is more susceptible to heinz bodies?
why? |
-cats are more susceptible because not removed as effectively by the spleen; hemoglobin conformation is different
-5% heinz bodies is normal in cats |
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What are heinz bodies?
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-HGB precipitates under cell membrane after oxidative damage that is irreversible
-this causes a membrane abnormality -splenic macrophages "pit" the Heinz bodies -OR in more severe cases, Heinz bodies weaken the RBC membrane and the cells lyse in circulation -this causes RBC ghosts due to increased membrane fragility |
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What are some causes of oxidative damage that eventually cause heinz bodies?
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onions, garlic, acetaminophin, zinc, red maple; cats are more susceptible
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What happens with intravascular hemolysis?
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-red cells are lysed in circulation and spill out the hemoglobin
-cause hemoglobinemia --> instead of clear, you see a red tinged plasma because there is hemoglobin free in circulation |
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With intravascular hemolysis, what it the relationship of HGB X 3 to PCV?
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HGB X 3 > PCV
-they normally are about equal to each other -MCHC is also increased |
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Why is it important with intravascular hemolytic anemia to tie up the free hemoglobin?
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(1) need to conserve the Fe (HGB --> heme --> Fe and bilirubin
(2) hemoglobin can be toxic to renal tubules (the Fe in it) - more in horses and people |
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What does Fe in the renal tubules cause?
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-causes redox reactions
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What recovers and binds free hemoglobin as a result of intravascular hemolysis
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-the haptoglobin recovery system (the liver produces the haptoglobin)
-haptoglobin binds free hemoglobin -the hemoglobin-haptoglobin complex is huge and it is taken up by the hepatocyte |
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Describe the signs of intravascular hemolysis.
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-acute
-may present BEFORE regeneration -hemoglobinemia -+/- hemoglobinuria if severe -hyperbilirubinemia -bilirubinuria |
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Describe extravascular hemolysis.
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-chronic
regenerative response -normal or increased plasma proteins -+/-hyperbilirubinemia if acute or severe |
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What do you call increased PCV?
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Erthrocytosis or polycythemia
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What are some examples of relative polycythemia?
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-hemoconcentration (dehydration, fluid shifts
-redistribution (excitement) |
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What are some examples of absolute polycythemia?
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Primary - polycythemia vera (neoplasia)
- secondary - increased EPO |
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What is the number one WBC is a cow and rabbit?
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lymphocyte
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What is used to count leukocytes?
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electronic particle counter
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What is used for a differential white cell count?
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absolute count = Total WBC x %
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What does a left shift mean?
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increased numbers of band neutrophils
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What is the difference of where RBCs and WBCs work?
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RBCs - inside vessels (oxygen transport)
WBCs - at tissue level |
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What is the function of leukocytes?
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-fight pathogens --> infectious agents (bacterial, virus, rickettsial)
-neutrophils are the first line of defense |
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The total number of blood neutrophils consists of what?
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circulating neutrophil pool and marginal neutrophil pool
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Name three types of neutrophilia?
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(1) excitement/physiological/epinephrine
(2) stress/corticosteroids (3) inflammation |
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What other changes occur with neutrophilia caused by excitement/physiological?
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-mature neutrophilia
-lymphocytosis -erythrocytosis -thrombocytosis |
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Why does erythrocytosis and thrombocytosis occur with neutrophilia caused by excitement?
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-splenic contraction - increased hematocrit and oxygen carrying capacity (epinephrine response)
-platelets |
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How long does epinephrine neutrophilia last and what type of neutrophilia is it?
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-transient - 20 minutes
-increased heart rate, blood flow |
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Why does neutrophilia truly occur with excitement?
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-normally just circulating neutrophils are sampled from a population, but when epinephrine is excreted, blood speeds up and the marginal neutrophils join the circulating neutrophils
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What is seen on a stress leukogram?
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-leukocytosis
-neutrophilia -LYMPHOPENIA -Monocytosis -Eosinopenia (maybe) |
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What is the difference in length between neutrophila caused by epinephrine and stress?
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-Epinephrine: short term, transient, 20 mintues
- stress/steroid: long term, severe, hours - days |
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What are causes of a stress leukogram?
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-severe physical or emotional stress
-hyperadrenocorticism -iatrogenic |
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What causes the neutrophilia due to stress?
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-decreased margination
-increased bone marrow release |
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How long do neutrophils stay in the factory and how many divisions take place?
warehouse? |
-2.5 days with 5 divisions
-2.5 days |