Erythron and Hematology Practice Flashcards

Vocabulary flashcards covering the erythron, CBC parameters, RBC indices, types of anemia, polycythemia, and erythrocyte morphology based on the lecture notes.

RBC Count

The number of erythrocytes in a specific volume of blood, typically measured via an automated cell counter.

Hemoglobin (HGB)

The amount of hemoglobin in a specific volume of blood, measured using a spectrophotometer (Hemoglobinometer).

PCV / HCT

The percentage of blood volume occupied by Red Blood Cells (RBCs), often determined by centrifugation.

MCV (Mean Corpuscular Volume)

Measures the average size of RBCs, calculated using the formula: $MCV = \frac{PCV \times 10}{RBC\text{ count}}$. It classifies cells as microcytic, normocytic, or macrocytic.

MCHC (Mean Corpuscular Hemoglobin Concentration)

Measures the hemoglobin concentration within RBCs using the formula: $MCHC = \frac{HGB \times 100}{PCV}$. It classifies cells as hypochromic or normochromic.

Macrocytosis ($\uparrow MCV$)

An increase in mean corpuscular volume often caused by reticulocytosis, agglutination, or specific breeds like Poodles.

Microcytosis ($\downarrow MCV$)

A decrease in mean corpuscular volume often associated with iron deficiency, portosystemic shunts, or Akita/Shiba breeds.

Agglutination

Irregular, grape-like clusters of RBCs caused by antibodies binding adjacent erythrocytes; this persists even after saline dilution.

Rouleaux Formation

Linear stacking of RBCs resembling a stack of coins due to increased plasma proteins; this disperses after saline dilution.

Anemia

A condition characterized by a decreased RBC count, hemoglobin concentration, or PCV, resulting in reduced oxygen delivery to tissues.

Polycythemia

A condition characterized by an increased RBC count, hemoglobin, and PCV.

Erythropoietin (EPO)

A hormone released by the kidneys in response to renal hypoxia that stimulates the bone marrow to increase erythropoiesis.

Regenerative (Responsive) Anemia

Anemia characterized by active bone marrow erythropoiesis, polychromasia, and reticulocytosis, typically evident after $2\text{--}3$ days.

Non-Regenerative (Non-Responsive) Anemia

Anemia where there is inadequate erythropoiesis or a bone marrow disorder, characterized by an absence of reticulocytosis.

Polychromasia

The presence of immature RBCs (polychromatophils) with blue-gray cytoplasm on a blood smear (using Wright, Giemsa, or Diff-Quik stains) due to residual RNA.

Reticulocyte

Immature RBCs containing residual RNA visible as a reticular blue network when stained with a supravital stain such as New methylene blue.

Hemorrhagic Anemia

Anemia caused by the loss of whole blood, often resulting in persistent hypoproteinemia.

Hemolytic Anemia

Anemia caused by increased RBC destruction, leading to a decreased RBC lifespan.

Extravascular Hemolysis

RBC destruction occurring in the spleen and liver macrophages, often characterized by spherocytes and autoagglutination.

Intravascular Hemolysis

RBC lysis occurring within the blood vessels, often resulting in hemoglobinemia, hemoglobinuria, and the presence of ghost cells.

Relative Polycythemia

An increase in PCV where total red cell mass is normal; causes include hemoconcentration (dehydration) or redistribution (splenic contraction).

Absolute Polycythemia

An increase in total red cell mass with normal plasma volume and protein, categorized as Primary (Polycythemia Vera) or Secondary (driven by EPO).

Spherocytes

Small, dense RBCs lacking central pallor, commonly associated with Immune-mediated hemolytic anemia (IMHA).

Schistocytes

Fragmented RBCs commonly seen in conditions like DIC, vasculitis, or heartworm disease.

Heinz bodies

Denatured hemoglobin within RBCs resulting from oxidative injury.

Howell-jolly bodies

Small, round nuclear remnants found within erythrocytes.

Dacrocytes

Erythrocytes with a teardrop-shaped morphology.

Echinocytes

Spiculated RBCs with uniform, short projections across the cell surface.

Acanthocyte

RBCs with irregular, finger-like projections.

Eccentrocyte

A red blood cell where the hemoglobin has shifted to one side, typically due to oxidative damage.

Hypochromasia

A decrease in hemoglobin concentration within RBCs, leading to an enlarged area of central pallor.