Introduction to Hematology Flashcards

Vocabulary practice flashcards covering fundamental hematology topics, including blood composition, acute phase reactants, RBC indices, cell morphology, inclusions, white blood cell types, and blood grouping.

Serum

Blood plasma minus the clotting factors, derived from a blood specimen that has not been anti-coagulated.

Acute Phase Reactants (APRs)

Substances (usually proteins) that change their serum concentration by >25% in response to inflammatory cytokines such as IL-1, IL-6, and TNF\text{\alpha}.

Negative Acute-Phase Proteins

Plasma proteins (such as albumin, pre-albumin, transferrin, and antithrombin) that decrease during inflammation, possibly to conserve amino acids for producing positive acute-phase proteins.

Heme Unit

A complex composed of four pyrrole rings (protoporphyrin) held together by one atom of iron in its reduced (ferrous, $\text{Fe}^{+2}$) form.

Hemoglobin Molecule

A red blood cell protein composed of 4 globin polypeptide subunits and 4 heme units, capable of binding up to 4 molecules of $\text{O}_2$.

Bilirubin

A waste product derived from the cleaved protoporphyrin complex during hemoglobin degradation that is excreted rather than recycled.

Mean Corpuscular Volume (MCV)

A standard CBC index measuring average red blood cell volume, where values below normal indicate microcytosis and values above normal indicate macrocytosis.

Red Cell Distribution Width (RDW)

An erythrocyte index that measures variation in RBC size; an elevated RDW indicates anisocytosis (a divergent population of red blood cells of different sizes).

Mean Cell Hemoglobin Concentration (MCHC)

An index correlating red blood cell hemoglobin content with cell volume, normally valued at $34 \pm 2\,\text{g/dl}$.

Poikilocytosis

The presence of abnormally shaped red blood cells on a blood smear.

Macroovalocytes

Large, oval-shaped red blood cells characteristic of a megaloblastic process caused by vitamin B12 or folic acid deficiency.

Spherocytes

Hyperchromic, spherical red blood cells lacking central pallor, associated with hereditary spherocytosis (due to spectrin deficiency) and autoimmune hemolytic anemia.

Schistocytes

Fragmented erythrocytes caused by mechanical destruction within vascular spaces, seen in hemolytic anemia, TTP, DIC, or prosthetic heart valves.

Tear Drop Cells

Abnormally shaped erythrocytes commonly found in extramedullary hematopoiesis (EMH) occurring in response to bone marrow failure.

Hypochromasia

A condition where the central zone of pallor in red blood cells exceeds one-third of the cell's diameter, as seen in iron deficiency anemia.

Rouleaux

Stacked chains of red blood cells caused by increased serum proteins (such as fibrinogen and globulins), which accelerate erythrocyte sedimentation rate (ESR).

Reticulocytes

Immature, non-nucleated red blood cells containing a reticular network of residual ribosomal RNA that circulate for approximately one day before full maturation.

Howell-Jolly Bodies

Red blood cell cytoplasmic inclusions consisting of nuclear chromatin (DNA) remnants, indicating functional or structural asplenia.

Basophilic Stippling

Small peripheral dots in red blood cells representing ribosomal precipitates, seen in lead poisoning, heavy metal toxicity, thalassemias, and alcohol abuse.

Heinz Bodies

Red blood cell inclusions formed from denatured hemoglobin, characteristically seen in G6PD deficiency.

Döhle Bodies

Light blue-gray, oval basophilic inclusions in the peripheral cytoplasm of neutrophils, representing remnants of the rough endoplasmic reticulum.

Band Cell

An immature neutrophil with a uni-lobar nucleus, whose presence in elevated numbers in peripheral blood indicates bone marrow stress or infection.

Hyper-segmented Neutrophil

A neutrophil possessing five or more nuclear lobes, classically observed in megaloblastic processes caused by vitamin B12 or folate deficiency.

Leukemoid Reaction

A severe non-leukemic elevation in white blood cell count exceeding $50,000/\mu\text{L}$, usually caused by major infection or inflammation.

NAACP Mnemonic

A mnemonic for the differential diagnosis of eosinophilia: Neoplastic, Asthma, Allergic reactions, Collagen vascular disease, and Parasites.

Natural Killer (NK) Cells

Large granular lymphocytes of the innate immune system that detect and eliminate tumor cells and virally infected cells by scanning cell surfaces.

Atypical Lymphocytes

Large lymphocytes with expanded cytoplasm and prominent nucleoli, seen in conditions like infectious mononucleosis and leukemia.

Monocytes

The largest circulating white blood cells, featuring a folded ("butt-shaped") nucleus, which migrate into tissues to become macrophages or histiocytes.

Platelets (Thrombocytes)

Anuclear cytoplasmic fragments originating from megakaryocytes in the bone marrow that degranulate to initiate clotting and tissue repair.

D Antigen

A major subtype of Rh antigens that defines Rh positive status; exposure to it in Rh-negative individuals leads to the production of anti-D IgG antibodies.

RhoGAM

An anti-Rh antibody administered to Rh-negative mothers to prevent B-lymphocyte sensitization against the D antigen and avoid fetal hemolytic disease.

Smudge Cells

Damaged lymphocytes undergoing apoptosis visible on blood smears from patients with B-cell chronic lymphocytic leukemia (CLL).

Hemozoin

An insoluble crystalline pigment formed by the Plasmodium parasite to detoxify consumed hemoglobin heme, which is ingested by monocytes during malaria.