Hematopoietic Cells, Disorders & Hemostasis – Review Flashcards

A comprehensive set of question-and-answer flashcards covering hematopoiesis, white-cell disorders, anemias, and hemostatic abnormalities for exam preparation.

Who is referred to as the "father of hematology" and what key protein did he isolate?

William Hewson; he isolated fibrinogen (called it coagulable lymph).

Which hematologist developed the hematocrit tube still used today and authored the first clinical hematology textbook?

Maxwell Myer Wintrobe.

From which two common progenitors do all blood cells arise?

Common myeloid progenitor and common lymphoid progenitor derived from hematopoietic stem cells.

Name two central and two peripheral lymphoid organs.

Central: bone marrow, thymus. Peripheral: lymph nodes, spleen (liver also prenatal).

Where in bone marrow are megakaryocytes and erythroblasts typically located?

Megakaryocytes near sinusoids; erythroblasts near 'nurse' macrophages.

What are the two main populations of stem cells found in bone marrow niches?

Hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs).

Which growth factor is primarily responsible for erythrocyte production?

Erythropoietin (Epo).

During fetal development, which organs are major sites of hematopoiesis after the yolk sac phase?

Liver and spleen.

What is leukopenia?

A decrease in the number of white blood cells in the blood.

Define leukocytosis.

An increase in the number of white blood cells, often reactive to inflammation or infection.

What is the most common cause of agranulocytosis?

Drug toxicity from agents such as alkylating agents and antimetabolites used in cancer therapy.

Below what absolute neutrophil count do serious infections become most likely?

Below 500 neutrophils per mm³.

Name four factors that influence the peripheral leukocyte count.

Size of precursor/storage pools, rate of release from marrow, proportion in marginal pool, rate of extravasation into tissues.

What is lymphadenitis?

Inflammatory enlargement of lymph nodes, which can be acute or chronic.

Which virus is frequently associated with hemophagocytic lymphohistiocytosis (HLH)?

Epstein-Barr virus (EBV).

List the four major categories of white-cell neoplasms.

Acute leukemias, chronic leukemias, Hodgkin lymphomas, non-Hodgkin lymphomas.

What distinguishes acute from chronic leukemia in terms of cell maturity?

Acute: accumulation of immature blasts; Chronic: proliferation of more mature, differentiated cells.

Which leukemia is most common in children and often involves NOTCH1 or PAX5 mutations?

Acute Lymphoblastic Leukemia (ALL).

What cell type is characteristic on peripheral smear in Chronic Lymphocytic Leukemia?

Smudge cells (fragile mature B-cells).

Which acute myeloid leukemia subtype with t(15;17) carries a high risk of DIC and is treated with ATRA?

Acute Promyelocytic Leukemia (APML).

Which lymphoma shows a nodular pattern with centrocytes and is associated with t(14;18) BCL2 overexpression?

Follicular lymphoma.

What is the most common non-Hodgkin lymphoma and what gene is frequently rearranged?

Diffuse Large B-Cell Lymphoma (DLBCL); BCL6 gene.

Which aggressive B-cell tumor is characterized by a MYC translocation and "starry sky" histology?

Burkitt lymphoma.

Name the giant tumor cells pathognomonic for classical Hodgkin lymphoma.

Reed-Sternberg cells.

Which plasma-cell neoplasm presents with lytic bone lesions, M-protein spike and Bence Jones proteins?

Multiple myeloma.

What classic peripheral smear finding is seen in multiple myeloma due to high immunoglobulin levels?

Rouleaux formation of red blood cells.

List the three principal diagnostic modalities for hematologic malignancies.

Morphology (smear/biopsy), immunophenotyping (flow cytometry/IHC), cytogenetics (FISH, PCR).

Define anemia.

Reduction in total red-cell mass or hemoglobin leading to decreased oxygen-carrying capacity.

What are the four main etiologic mechanisms leading to anemia?

Impaired production, blood loss, increased destruction (hemolysis), or combinations thereof.

Which lab finding usually rises in hemolytic anemia due to increased marrow response?

Reticulocyte count.

Iron accumulation in tissues secondary to hemolysis is called what?

Hemosiderosis.

Which sickle-cell crisis results from splenic congestion with red cells?

Sequestration crisis.

What genetic defect produces sickle cell disease?

Point mutation in β-globin producing hemoglobin S.

In adult males, what is the normal reference range for hemoglobin?

13.6–17.2 g/dL.

Purpura and petechiae are typical of defects in which hemostatic component?

Platelet or primary hemostatic defects.

Which inherited bleeding disorder stems from deficiency of Factor VIII?

Hemophilia A.

How is thrombocytopenia defined numerically?

Platelet count <150,000 /µL (clinically often <100,000 /µL significant).

Name three common causes of acquired thrombocytopenia.

Viral infections, drug-induced marrow suppression, nutritional B12 or folate deficiency (among others).

What triad of laboratory/clinical features typifies disseminated intravascular coagulation (DIC)?

Widespread microvascular thrombosis, consumption of platelets/coagulation factors, and simultaneous bleeding.

List four common triggers for DIC.

Sepsis, major trauma, certain cancers, obstetric complications.

At what platelet count is thrombocytosis defined?

450,000 /µL.

Which two gene mutations are most frequently seen in essential thrombocythemia?

JAK2 and CALR mutations.

What drug class is first-line in treating APML by inducing differentiation of blasts?

All-trans retinoic acid (ATRA).

Which immunophenotypic markers define CLL B-cells?

CD5 and CD23 positivity.

What is Richter syndrome?

Transformation of CLL into an aggressive large-cell lymphoma (usually DLBCL).

How does leukemic infiltration typically manifest in acute leukemias?

Marrow failure with anemia, thrombocytopenia, neutropenia; sometimes organ infiltration or mediastinal mass (T-ALL).

Which lymphoma subtype has strong association with EBV and jaw involvement in endemic areas?

Endemic Burkitt lymphoma.

What cytokine pathway activation is common to many classical Hodgkin lymphoma cases?

NF-κB pathway activation.

What blood smear finding suggests AML and is MPO positive?

Auer rods in myeloblasts.

Which factor primarily stimulates platelet production from megakaryocytes?

Thrombopoietin (TPO).

What lab test differentiates hemophilia (intrinsic pathway defect) from extrinsic pathway disorders?

Prolonged activated partial thromboplastin time (aPTT) with normal PT.

Which form of thrombocytopenia is caused by antibodies against platelets?

Immune Thrombocytopenic Purpura (ITP).

Why can splenectomy produce secondary thrombocytosis?

Loss of platelet reservoir causes more platelets to remain in circulation.

Which anemia type is characterized by microcytosis with low reticulocyte index?

Iron deficiency anemia.

Name two hyperproliferative macrocytic anemias due to vitamin deficiency.

Vitamin B12 deficiency and folate deficiency anemias.

What physiologic cardiac change compensates for chronic anemia?

Increased heart rate and stroke volume producing hyperdynamic circulation.

Which diagnostic hallmark differentiates hemolytic from non-hemolytic anemias early?

Elevated reticulocyte count (appropriate response).

What is the key histologic cell arrangement in bone marrow biopsies of multiple myeloma?

Sheets of monoclonal plasma cells replacing normal marrow.