Comprehensive Hematology and Hemostasis Practice Flashcards

A set of 100 vocabulary flashcards reviewing hematology, blood cell development, hemoglobin dynamics, laboratory testing, leukocyte disorders, leukemias, and primary/secondary hemostasis based on comprehensive lecture transcript notes.

Hypovolemia

A state of decreased blood volume resulting from conditions such as blood loss, loss of plasma, or severe dehydration.

Hypervolemia

A state of increased blood volume, which can be caused by conditions such as blood transfusion.

Thixotropic gel

An inert material that undergoes a temporary change in viscosity during centrifugation to serve as a separation barrier between the liquid (serum or plasma) and cellular components.

Ethylenediamine tetraacetic acid (EDTA)

An anticoagulant that removes ionized calcium ($Ca^{2+}$) through an irreversible chelation process, forming an insoluble calcium salt to prevent clotting.

Platelet satellitosis

An in vitro phenomenon where platelets adhere around neutrophils in blood anticoagulated with EDTA, leading to a falsely decreased automated platelet count.

Sodium citrate

An anticoagulant used in light blue top tubes for coagulation studies that functions by binding calcium to form a soluble complex.

Heparin

A natural acid mucopolysaccharide anticoagulant that prevents clotting by inactivating thrombin and other coagulation factors.

Retrogression

The developmental process of replacing active red bone marrow with adipocytes (yellow marrow), restricting active marrow in adults to flat bones and proximal long bones.

Medullary hematopoiesis

Blood cell production and development that takes place within the bone marrow cavity, serving as the primary site in healthy adults.

Extramedullary hematopoiesis (EMH)

The formation and activation of blood cells outside the bone marrow, occurring mainly in the liver and spleen during bone marrow dysfunction or excessive demand.

M:E Ratio

The ratio of myeloid to erythroid precursor cells in the bone marrow, which normally varies from $1.5:1$ to $3.3:1$ in healthy adults.

Osteoblasts

Bone-forming cells in the bone marrow that exhibit a water-bug or comet appearance and are frequently confused with plasma cells.

Osteoclasts

Large, multinucleated bone-resorbing cells present in the bone marrow that are frequently mistaken for megakaryocytes.

Erythropoietin (EPO)

A glycoprotein growth factor produced by the peritubular cells of the kidney that acts as the primary humoral regulator of erythropoiesis.

Pronormoblast

The earliest morphologically recognizable erythroid precursor, characterized by a large nucleus with fine chromatin, 1 to 2 nucleoli, an N:C ratio of $8:1$, and deeply basophilic cytoplasm.

Basophilic normoblast

An erythroid precursor stage lasting slightly over 24 hours, featuring an N:C ratio of $6:1$, partially clumped chromatin forming a wheel-spoke pattern, and rich blue cytoplasm.

Polychromatophilic normoblast

An erythroid precursor stage characterized by gray-blue cytoplasm containing pink hemoglobin and blue ribosomes, absence of nucleoli, and an N:C ratio decreasing from $4:1$ to $1:1$.

Orthochromic normoblast

The final nucleated stage of erythropoiesis, characterized by a pyknotic condensed nucleus, salmon-pink cytoplasm, and inability to undergo cellular division.

Pyrenocyte

The enveloped extruded nucleus ejected from an orthochromic normoblast, which is subsequently engulfed and digested by bone marrow macrophages.

Reticulocyte

An immature, non-nucleated erythrocyte that contains residual ribosomal RNA, which precipitates as a blue meshwork or dots when stained with a supravital dye.

Stress reticulocytes

Larger, polychromatic reticulocytes prematurely released from the bone marrow into peripheral circulation during severe anemia to compensate for red cell loss.

Asynchronous erythropoiesis

A maturation imbalance where nuclear and cytoplasmic development progress at different rates, such as cytoplasm lagging in iron deficiency or nucleus lagging in vitamin B12/folate deficiency.

Spectrin

A major cytoskeletal peripheral protein in the erythrocyte membrane that provides shape, flexibility, and deformability essential for cell survival in microvasculature.

Embden-Meyerhof pathway

The major non-oxidative, anaerobic glycolytic pathway in red blood cells that metabolizes $90\%$ of cellular glucose to generate 2 net molecules of ATP.

Pyruvate kinase deficiency

The most common enzyme deficiency of the Embden-Meyerhof glycolytic pathway, leading to diminished ATP production and nonspherocytic hemolytic anemia.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency

The most common RBC enzyme defect worldwide, impairing the hexose monophosphate shunt and exposing hemoglobin and membrane lipids to oxidative damage.

Methemoglobin reductase pathway

An erythrocyte metabolic pathway that utilizes NADH generated by glycolysis to keep hemoglobin iron reduced in its functional ferrous ($Fe^{2+}$) state.

Rapaport-Luebering pathway

A metabolic shunt off the Embden-Meyerhof pathway responsible for generating $2,3\text{-BPG}$, which regulates oxygen release from hemoglobin to tissues.

P50 value

The partial pressure of oxygen at which hemoglobin is $50\%$ saturated with oxygen, normally $26.52\,mmHg$ in whole blood under standard physiological conditions.

Bohr effect

The physiological influence of pH and carbon dioxide concentration on hemoglobin's affinity for oxygen, facilitating oxygen release in tissues.

Extravascular hemolysis

The destruction of senescent or abnormal red blood cells outside blood vessels, primarily via phagocytosis by macrophages in the spleen and liver.

Intravascular hemolysis

The breakdown and fragmentation of red blood cells directly within the circulating blood, releasing free hemoglobin into plasma.

Haptoglobin

An acute-phase plasma transport protein that binds free hemoglobin released during intravascular hemolysis to prevent renal loss of iron.

Protoporphyrin IX

An organic tetrapyrrole ring structure that combines with a central atom of divalent ferrous iron ($Fe^{2+}$) to form heme.

Aminolevulinic acid (ALA) synthase

The rate-limiting mitochondrial enzyme that initiates heme biosynthesis by condensing glycine and succinyl-CoA into aminolevulinic acid.

Ferrochelatase

The mitochondrial enzyme, also known as heme synthase, that inserts ferrous iron ($Fe^{2+}$) into the protoporphyrin IX ring during the final step of heme synthesis.

Oxyhemoglobin

The relaxed (R) state form of hemoglobin bound with oxygen, predominantly present in arterial circulation.

Deoxyhemoglobin

The tensed (T) state form of hemoglobin lacking oxygen, predominantly present in venous circulation.

Carboxyhemoglobin

A hemoglobin derivative formed by binding carbon monoxide, which exhibits over 200 times higher affinity for CO than oxygen and imparts a brilliant cherry-red color to blood.

Methemoglobin

A non-functional hemoglobin variant containing oxidized ferric iron ($Fe^{3+}$) that cannot transport oxygen and causes a chocolate-brown discoloration of blood.

Sulfhemoglobin

An irreversible, non-functional hemoglobin derivative containing sulfur that cannot be reduced back to hemoglobin and imparts a greenish-black color to blood.

Ferritin

The primary water-soluble intracellular storage protein complexed with ferric ($Fe^{3+}$) iron, serving as an acute-phase reactant and key index of body iron stores.

Hemosiderin

A water-insoluble, degraded form of ferritin found in macrophages of the liver, spleen, and bone marrow that stains positive with Perl's Prussian blue.

Hepcidin

A liver-synthesized peptide hormone that functions as the master regulator of systemic iron metabolism by inducing internal degradation of ferroportin.

Ferroportin

The sole known cellular transmembrane protein responsible for exporting iron across cell membranes from enterocytes, macrophages, and hepatocytes into plasma.

Hereditary hemochromatosis

An autosomal recessive genetic disorder characterized by abnormally high gastrointestinal iron absorption, leading to progressive iron overload, bronze skin, and organ failure.

Corrected WBC count

A calculated leukocyte adjustment used when 5 or more NRBCs per 100 WBCs are seen on a differential smear, preventing false overestimation of the total leukocyte count.

New Methylene Blue

The preferred supravital stain used to precipitate residual ribosomal RNA in living reticulocytes into a visible blue network or dots.

Miller disk

A specialized calibrated microscope eyepiece grid containing a small square (B) that is $1/9$ the area of the large square (A), used to standardize manual reticulocyte counts.

Reticulocyte Production Index (RPI)

A calculated index adjusting reticulocyte percentage for anemia and maturation time; a value greater than 3 indicates an adequate bone marrow response.

Cyanmethemoglobin method

The reference photometric laboratory method for measuring total hemoglobin, wherein blood is diluted in Drabkin's reagent and measured at a wavelength of $540\,nm$.

Drabkin's reagent

A hemoglobin assay reagent composed of potassium ferricyanide, potassium cyanide, non-ionic detergent, and dihydrogen potassium phosphate.

Trapped plasma

The small amount of plasma remaining enclosed within the packed erythrocyte column following centrifugation during microhematocrit determination.

Mean Cell Volume (MCV)

An erythrocyte index calculated as $\frac{Hct}{RBC\,ct} \times 10$, representing the average volume of individual red blood cells in femtoliters ($\text{fL}$).

Mean Cell Hemoglobin (MCH)

An erythrocyte index calculated as $\frac{Hb}{RBC\,ct} \times 10$, representing the average weight of hemoglobin per red blood cell in picograms ($\text{pg}$).

Mean Cell Hemoglobin Concentration (MCHC)

An erythrocyte index calculated as $\frac{Hb}{Hct} \times 100$, representing the average concentration of hemoglobin in a given volume of packed red blood cells in $\text{g/dL}$.

Red Cell Distribution Width (RDW)

The coefficient of variation of red blood cell volume expressed as a percentage, serving as an automated quantitative measurement of anisocytosis.

Zeta potential

The net negative charge on the surface of mature red blood cells caused by sialic acid groups, which naturally repels adjacent erythrocytes in plasma.

Rouleaux formation

The stacking arrangement of erythrocytes resembling rolls of coins, promoted by elevated positive plasma acute-phase proteins that diminish the zeta potential.

Electrical impedance

The Coulter counting principle based on measuring increases in electrical resistance created when a cell suspended in a conductive diluent passes through a small aperture.

Romanowsky stain

A polychrome stain defined as containing methylene blue (or its oxidation products) and an acidic halogenated fluorescein dye such as eosin.

Anisocytosis

A general hematologic term referring to an abnormal variation in the size of red blood cells on a peripheral blood smear.

Poikilocytosis

A general hematologic term referring to an abnormal variation in the shape of red blood cells on a peripheral blood smear.

Hereditary Spherocytosis

A congenital disorder caused by defects in RBC membrane skeletal proteins like spectrin or ankyrin, producing dense, round spherocytes with increased osmotic fragility.

Acanthocyte

A dense, spherical erythrocyte with 3 to 12 irregular, thorny projections, associated with abetalipoproteinemia, severe liver disease, and McLeod syndrome.

Echinocyte

An erythrocyte exhibiting short, blunt, regularly spaced spicules over its entire surface, commonly seen in uremia, pyruvate kinase deficiency, or as a drying artifact.

Codocyte (Target cell)

An erythrocyte featuring a central area of hemoglobin surrounded by a clear ring and outer hemoglobin rim, associated with liver disease and thalassemias.

Schistocyte

A fragmented red blood cell resulting from mechanical shear injury against microvascular fibrin strands, characteristic of MAHA, DIC, and TTP.

Dacryocyte

A teardrop- or pear-shaped red blood cell formed when erythrocytes are squeezed through fibrous marrow spaces or the spleen, typical of primary myelofibrosis.

Howell-Jolly bodies

Smooth, round nuclear remnants composed of DNA that stain dark blue-purple on Wright-stained smears, seen post-splenectomy and in megaloblastic anemia.

Basophilic stippling

Coarse or fine dark blue-purple punctate granules distributed throughout the cytoplasm of erythrocytes, caused by aggregated ribosomes and RNA in lead poisoning.

Heinz bodies

Inclusions formed by denatured, precipitated hemoglobin attached to the inner RBC membrane, visible only with supravital stains in G6PD deficiency.

Pappenheimer bodies

Irregular clusters of small, light-to-dark blue iron granules situated near the cell periphery that stain positive with Perl's Prussian blue.

Cabot rings

Red-to-purple loop-like or figure-eight ring structures in erythrocytes composed of remnants of the mitotic spindle microtubules.

Ringed sideroblast

An abnormal nucleated erythroid precursor containing excess non-heme iron particles accumulated in a collar around the nucleus within mitochondria.

Sickle cell anemia

A homozygous structural hemoglobinopathy ($Hb\,SS$) caused by a point mutation replacing glutamic acid with valine at position 6 of the $\beta$-globin chain.

Hb C disease

A homozygous hemoglobinopathy caused by substituting lysine for glutamic acid at position 6 of the $\beta$-globin chain, forming hexagonal dark crystals inside RBCs.

Alpha thalassemia

A quantitative globin defect caused by deletions or mutations affecting one or more of the four $\alpha$-globin genes on chromosome 16.

Hb H disease

An $\alpha$-thalassemia condition caused by deletion of 3 $\alpha$-globin genes, leading to formation of unstable $\beta_4$ tetramers that yield a golf-ball appearance on supravital stain.

Beta thalassemia major

A severe quantitative globin disorder caused by mutations in both $\beta$-globin genes on chromosome 11, resulting in severe anemia, skeletal deformities, and transfusion dependency.

Granulocyte Colony-Stimulating Factor (G-CSF)

The primary hematopoietic growth factor and cytokine responsible for stimulating the proliferation, differentiation, and maturation of granulocytes.

Myeloblast

The first morphologically identifiable granulocytic precursor in bone marrow, characterized by a large nucleus, fine chromatin, 2 to 5 nucleoli, and an N:C ratio of $4:1$.

Promyelocyte

A granulocytic precursor stage featuring a round nucleus with a paranuclear halo (hof) and the active synthesis of primary non-specific azurophilic granules.

Myelocyte

The final stage in the granulocytic series capable of cell division (mitosis) and the first stage to synthesize secondary specific granules.

Metamyelocyte

A non-dividing granulocytic precursor characterized by an indented or kidney-bean-shaped nucleus and the onset of tertiary granule synthesis.

Band cell

A mature-stage leukocyte precursor featuring an elongated curved C- or S-shaped nucleus without thin segmenting nuclear filaments.

Segmented neutrophil

A mature phagocytic granulocyte with 2 to 5 nuclear lobes connected by thin chromatin filaments, serving as the predominant WBC in adult peripheral blood.

Eosinophil

A mature granulocyte characterized by bilobed nuclei and large, refractile reddish-orange secondary granules containing major basic protein.

Basophil

The least common circulating leukocyte, containing dark purple to blue-black water-soluble granules rich in histamine and heparin that may obscure the nucleus.

Monocyte

The largest normal cell in peripheral blood, featuring blue-gray ground-glass cytoplasm, fine azure dust, folded nucleus, and strong positive non-specific esterase activity.

Pelger-Huët anomaly

An autosomal dominant disorder characterized by failure of neutrophil nuclear segmentation, producing bilobed pince-nez or unsegmented nuclei.

Döhle bodies

Small, pale blue cytoplasmic inclusions in neutrophils composed of remnant ribosomal RNA strands, seen in severe infections and inflammatory states.

Alder-Reilly anomaly

An inherited lysosomal storage disorder characterized by prominent, dense azurophilic granules in all leukocyte lines due to mucopolysaccharide accumulation.

Chédiak-Higashi syndrome

An autosomal recessive disease caused by LYST gene mutations, resulting in giant abnormal lysosomal granules, partial albinism, and severe immunodeficiency.

Auer rods

Reddish, needle-like azurophilic inclusions in blast cytoplasm formed by fused primary granules, characteristic of acute myeloid leukemia.

Reed-Sternberg cell

A giant binucleated lymphoid cell with prominent eosinophilic owl's-eye nucleoli, serving as the diagnostic histologic hallmark of Hodgkin lymphoma.

Philadelphia chromosome

A reciprocal translocation between chromosomes 9 and 22, $t(9;22)$, creating the $BCR-ABL1$ fusion gene characteristic of Chronic Myelogenous Leukemia.

Primary hemostasis

The initial rapid physiological response to vascular injury involving vasoconstriction, platelet adhesion, and aggregation to form a temporary platelet plug.

Von Willebrand factor (vWF)

A plasma glycoprotein synthesized by endothelial cells and megakaryocytes that anchors platelets to exposed subendothelial collagen via GP Ib/IX/V.

Prothrombin Time (PT)

A screening assay that measures the clotting time of extrinsic and common coagulation pathways (Factors VII, X, V, II, and I) in plasma.