Hematology and Erythropoiesis Vocabulary Flashcards

Comprehensive set of vocabulary flashcards covering red blood cell maturation, blood composition, hematopoiesis, red cell membrane dynamics, and erythrocyte destruction pathways based on the lecture notes.

Pronormoblast (Rubriblast)

The earliest morphologically recognizable red cell precursor, measuring $20\text{--}25\,\text{um}$ in diameter with a large nucleus containing $0\text{--}2$ nucleoli, a narrow dark blue cytoplasm rim, and a nuclear to cytoplasmic ratio of $8:1$.

Basophilic Normoblast

A red cell precursor measuring $16\text{--}18\,\text{um}$ in diameter with dense chromatin clumps, no nucleoli, deep blue cytoplasm with a perinuclear halo, and a nuclear to cytoplasmic ratio of $6:1$.

Polychromatophilic Normoblast

A red cell precursor measuring $12\text{--}14\,\text{um}$ in diameter with coarse chromatin, a thick nuclear membrane, and a widening cytoplasm with a lilac tint due to early hemoglobinization; nuclear to cytoplasmic ratio ranges from $2:1$ to $4:1$.

Orthochromatic Normoblast (NRBC)

A red cell precursor measuring $10\text{--}12\,\text{um}$ in diameter with a small condensed nucleus that is ultimately ejected, leaving a wide rim of pink cytoplasm; nuclear to cytoplasmic ratio ranges from $1:2$ to $1:3$.

Howell Jolly Bodies

Nuclear fragments occasionally remaining in the cytoplasm following the ejection of the nucleus from an orthochromatic normoblast.

Reticulocyte

An anucleate cell measuring $8\text{--}10\,\text{um}$ in diameter with faintly basophilic cytoplasm containing precipitated ribosomes visible with new methylene blue stain; remains in bone marrow for approximately $2\,\text{days}$ before entering peripheral circulation.

Mature Erythrocyte

A biconcave, anucleate cell measuring $7\text{--}8\,\text{um}$ in diameter with orange-pink cytoplasm, a pale central area occupying one-third of the cell area, and a mean corpuscular volume of $80\text{--}100\,\text{fl}$.

Hematology

A discipline derived from the Greek haima (blood) and logos (discourse), encompassing all blood cells, plasma composition, cellular fluids, and coagulation mechanisms.

Formed Elements

The cellular component of whole blood, making up about $45\%$ of total volume, comprising red blood cells ($43\%$), white blood cells ($1\%$), and platelets ($1\%$).

Buffy Coat

The narrow middle layer formed upon blood centrifugation containing white blood cells and platelets, located between the top plasma layer and bottom red cell layer.

Pluripotent Stem Cell

An unspecialized cell capable of self-renewal or differentiating into either the lymphoid lineage or a multipotent lineage for granulopoiesis, erythropoiesis, and thrombopoiesis.

Primary Lymphoid Tissues

Anatomical sites consisting of the bone marrow and thymus where T cell and B cell development takes place.

Secondary Lymphoid Tissues

Peripheral lymphoid organs consisting of the spleen and lymph nodes.

Medullary Hematopoiesis

The production and development of blood cells taking place inside the extravascular red marrow of the bone marrow.

Extramedullary Hemopoiesis

The formation and development of normal blood cells occurring outside the bone marrow, primarily in the liver and spleen.

Plasma

The straw-colored liquid component of blood constituting $55\%$ of total volume, made of $92\%$ water, $7\%$ proteins, and $1\%$ solutes with a pH of $7.35\text{--}7.45$.

Serum

The liquid portion left behind after blood is permitted to clot, which does not contain clotting factors.

Erythrocyte Membrane Composition

A complex phospholipid bilayer structure composed of $52\%$ protein, $40\%$ lipid, and $8\%$ carbohydrate.

Hexose Monophosphate Shunt

An auxiliary pathway responsible for $5\text{--}10\%$ of glucose metabolism in red blood cells that utilizes the enzyme glucose-6-phosphate dehydrogenase (G6PD).

Erythropoietin (EPO)

A heavily glycosylated hormone ($40\%$ carbohydrate, $165$ amino acids) produced $90\%$ in the renal peritubular complex and $10\%$ in the liver to stimulate red blood cell production during tissue hypoxia.

Hemostasis

The physiological mechanism responsible for maintaining blood as a fluid within circulation while forming a clot to stop bleeding upon blood vessel injury.

Ineffective Erythropoiesis

The normal intramedullary destruction process where $10\text{--}15\%$ of developing erythroblasts die inside the bone marrow and are ingested by macrophages prior to maturation.

Megaloblastic Erythropoiesis

An abnormal red cell maturation pattern caused by vitamin B12 or folic acid deficiency, characterized by defective DNA synthesis where nuclear maturation lags behind cytoplasmic hemoglobinization.

Megalocyte

An abnormally large red blood cell measuring $9\text{--}12\,\text{um}$ in diameter resulting from megaloblastic maturation.

Extravascular Destruction

The primary pathway accounting for $90\%$ of old red blood cell removal, performed by macrophages in the spleen, liver, and bone marrow.

Intravascular Destruction

The pathway accounting for $10\%$ of red blood cell destruction, occurring through cell membrane damage and lysis directly inside vascular channels.

Thrombopoietin

A specific hematopoietic growth factor cytokine that stimulates the proliferation and maturation of platelets.

Cluster Designations (CD)

Monoclonal antibody surface markers identified via flow cell cytometry, such as CD4 and CD8, used to characterize specific cells and monitor HIV progression.