Hematopoiesis and Bone Marrow Flashcards

Vocabulary flashcards covering key hematology concepts, cell differentiation stages, leukocyte types, and bone marrow components based on the lecture notes.

Hematology

The study of blood, including blood cells (RBCs, WBCs, platelets) and plasma, which makes up approximately $8\%$ of total body weight with an average volume of $4\text{--}6\,\text{L}$.

Segmented Neutrophil

A mature granulocyte containing 2 to 5 nuclear lobes connected by thin filaments.

Band Neutrophil

An immature granulocyte characterized by a single nuclear lobe with an indentation greater than half the width of the nucleus, where the margin can be traced continuously from one side to the other without filaments.

Eosinophil

A granulocyte featuring a blue-reddish, coarsely clumped nucleus (typically banded or bi-lobed) and cytoplasm packed with large, uniform, evenly dispersed orange-red secondary granules.

Basophil

A granulocyte containing large, dark blue-black, water-soluble secondary granules of varying number and shape that obscure a blue-reddish nucleus.

Hematopoiesis

The process of cellular blood production and development.

Extramedullary Hematopoiesis

Blood cell production taking place outside the bone marrow, specifically in the liver and spleen, during times of increased cell demand.

Reticulocyte

A diffusely basophilic erythrocyte containing residual RNA that stains in a filamentous formation when stained with New Methylene blue.

Erythropoietin

A hormonal glycoprotein growth factor produced by the kidney during tissue hypoxia or anemia to stimulate erythropoiesis.

Erythrocyte

A mature, anucleate, biconcave red blood cell measuring $6\text{--}9\,\mu\text{m}$ with a volume of $90\,\text{femtoliters}$ that functions to transport oxygen to tissues and carbon dioxide away from tissues.

Myelopoiesis

The process of production and maturation of granulocytes (neutrophils, eosinophils, and basophils).

Mitotic Pool

A granulocyte bone marrow pool consisting of stem cells, myeloblasts, promyelocytes, and myelocytes that are actively dividing.

Maturation Pool

A granulocyte bone marrow pool consisting of metamyelocytes and bands where cell division and DNA synthesis have ceased.

Storage Pool

A bone marrow pool containing mature granulocytes held in reserve before release into circulation.

Circulating Pool

The pool of mature granulocytes circulating freely in the blood stream, representing half of the granulocytes released from the bone marrow.

Marginating Pool

The pool of mature granulocytes lining the vessel walls of organs such as the spleen, liver, and lungs, representing half of the granulocytes released from the bone marrow.

Mast Cell

A tissue basophil formed when circulating basophils migrate into tissues, containing larger secondary granules.

Monocyte

The largest cell in peripheral circulation, characterized by a folded/convoluted nucleus with lacy chromatin and dull gray-blue cytoplasm with a ground-glass appearance.

Histiocyte

A tissue macrophage derived from monocytes that cleanses hematopoietic tissue and acts as a central storage macrophage delivering iron to developing erythroblasts.

Plasmacyte

An end-stage B lymphocyte with deep blue cytoplasm and an eccentric nucleus that synthesizes immunoglobulins.

Flame Cell

A plasma cell characterized by reddish cytoplasm, associated with the synthesis of Immunoglobulin A (IgA).

Thrombopoietin

The growth factor that stimulates megakaryocyte production and platelet release.

Megakaryocyte

The largest cell in the bone marrow, which produces platelets by fragmenting its cytoplasm around its outer edges.

Platelet

An anucleate cytoplasmic fragment of a megakaryocyte measuring $1\text{--}4\,\mu\text{m}$ with light blue cytoplasm and small reddish granules, responsible for maintaining hemostasis.

Cytokines

Soluble factors including colony-stimulating factors, growth factors, and interleukins that regulate cell proliferation, differentiation, maturation, and survival.

Cluster Designation

A nomenclature system used to classify cell antigens and cell surface markers using monoclonal antibodies.

Hematogones

Normal B-lymphocyte progenitor cells in bone marrow whose morphologic features resemble leukemic lymphoblasts.

Erythropoietic Island

A distinct anatomical structure in the bone marrow consisting of a central storage macrophage surrounded by a cluster of maturing erythroblasts.

Osteoblast

A bone matrix-synthesizing cell found in bone marrow, containing fine chromatin, prominent nucleoli, and a detached perinuclear halo.

Osteoclast

A large, multinucleated bone-remodeling cell in the bone marrow containing an uneven number of separated oval nuclei, blue granules, and frayed cytoplasmic margins.

Myeloid to Erythroid Ratio

The numerical ratio comparing all granulocytes and their precursors to all nucleated red blood cells and their precursors in the bone marrow, with an average normal value of $3.1$.