The Hematopoietic and Lymphoid Systems Practice Flashcards

Comprehensive vocabulary flashcards covering the hematopoietic and lymphoid systems, including anemias, leukemias, lymphomas, and coagulation disorders.

Haemopoietic stem cell

A stem cell capable of self-renewal and differentiation into all blood cell lineages in the bone marrow.

Lymphoid stem cell

A precursor cell that gives rise to T lymphocytes, B lymphocytes, and NK cells.

Erythroid stem cell

A stem cell lineage that specifically leads to the production of Erythrocytes.

Megakaryocyte

A large bone marrow cell responsible for the production of platelets.

Anemia

A reduction of blood oxygen carrying capacity, often associated with abnormal hemoglobin, reduced red blood cell count, or structural red blood cell abnormalities.

Mean corpuscular volume (MCV)

A red blood cell index used in a CBC to classify anemia based on the average size of the cells.

Mean corpuscular hemoglobin (MCH)

A red blood cell index measuring the average mass of hemoglobin per red blood cell.

Mean corpuscular hemoglobin concentration (MCHC)

A blood index measuring the average concentration of hemoglobin in a given volume of packed red blood cells.

Serum ferritin

A laboratory test used to assess iron stores in the body, specifically used to evaluate iron deficiency anemia.

Total Iron Binding Capacity (TIBC)

A lab test that measures the blood's capacity to bind iron with transferrin, used in the assessment of iron deficiency anemia.

Reticulocyte count

A measurement used to assess the bone marrow's response to anemia by counting immature red blood cells.

Coombs test

A laboratory test used to evaluate immune-mediated hemolysis in cases of suspected hemolytic anemia.

Hemoglobin electrophoresis

A laboratory technique used to identify different types of hemoglobin, essential for diagnosing thalassemia and sickle cell disease.

Osmotic fragility test

A genetic/laboratory test used specifically for the diagnosis of hereditary spherocytosis.

Philadelphia chromosome

A specific cytogenetic abnormality, identified as $t(9,22)$, found in Chronic Myelogenous Leukemia (CML).

Serum protein electrophoresis

A laboratory test used to detect abnormal protein levels, specifically utilized for diagnosing multiple myeloma.

Prothrombin Time (PT/INR)

A coagulation test used to evaluate the extrinsic pathway of the coagulation cascade.

Activated Partial Thromboplastin Time (aPTT)

A coagulation test used to evaluate the intrinsic pathway of the coagulation cascade.

D-dimer

A laboratory marker used to detect the presence of fibrin degradation products, often elevated in disseminated intravascular coagulation (DIC).

Plasma

The fluid component of blood.

Erythrocytes

Red blood cells responsible for transporting oxygen from lungs into peripheral tissues.

Leukocytes

White blood cells, which include neutrophils, eosinophils, basophils, monocytes, and lymphocytes.

Thrombocytes

Also known as platelets; blood components essential for hemostasis and thrombus formation.

Yolk sac

The primary site of hematopoiesis in the embryo.

Liver and Spleen

The primary sites of hematopoiesis during the fetal stage of development.

Adult hematopoietic bones

Bones such as the vertebrae, ribs, sternum, pelvis, and calvarium where blood cell production occurs in adults.

Hemoglobin molecule

A complex molecule consisting of four heme groups and four globins.

Aplastic anemia

A form of anemia caused by bone marrow failure and decreased hematopoiesis.

Myelophthisic anemia

A type of decreased hematopoiesis anemia caused by the displacement of marrow by tumors or other lesions.

Megaloblastic anemia

A form of anemia caused by deficiencies in Vitamin $B_{12}$ or folic acid, leading to abnormal red blood cell maturation.

Iron Deficiency Anemia

The most common form of anemia, characterized as hypochromic and microcytic.

Hypochromic

A term describing red blood cells that have decreased hemoglobin content, appearing paler than normal.

Microcytic

A term describing red blood cells that are smaller than the normal size.

Pernicious anemia

A specific type of Vitamin $B_{12}$ deficiency caused by a lack of gastric intrinsic factor or atrophic gastritis.

Intracorpuscular hemolytic anemia

Red blood cell destruction caused by structural abnormalities such as sickle cell anemia, thalassemia, or hereditary spherocytosis.

Extracorpuscular hemolytic anemia

Red blood cell destruction caused by external factors such as antibodies, infectious agents (malaria), or mechanical factors (DIC, prosthesis).

Hereditary Spherocytosis

A genetic defect in encoding ankyrin or the alpha/beta chain of spectrin, leading to the formation of spherocytes.

Spherocytes

Spherical-shaped red blood cells found in the peripheral blood of patients with hereditary spherocytosis.

Sickle Cell Anemia

A hemoglobinopathy caused by genetic abnormalities leading to hemoglobin polymerization and cell sickling.

Thalassemia

A group of genetic disorders characterized by abnormal hematopoiesis and imbalances in globin chain synthesis (alpha or beta).

Autoimmune hemolytic anemia

An immune-mediated destruction of red blood cells caused by autoantibodies.

Polycythemia Vera

A primary polycythemia characterized by atypical hematopoietic cell precursors and decreased erythropoietin.

Secondary polycythemia

An increase in red blood cells caused by hypoxia (heart/lung disease, high altitude) or excess erythropoietin production from tumors or kidney diseases.

Leukopenia

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

Leukocytosis

An increase in the total number of white blood cells in the peripheral blood.

Leukemia

A malignant disease involving white blood cell precursors in the bone marrow and peripheral blood, characterized by immature cells.

Lymphoma

Malignant diseases of lymphoid cells predominantly involving the lymph nodes.

Non-Hodgkin’s lymphoma (NHL)

One of the two large categories of lymphoma, which can involve lymph nodes, spleen, thymus, or extranodal sites.

Hodgkin’s lymphoma

A clinical and pathological category of lymphoma distinguished from non-Hodgkin's lymphoma.

HTLV-1

A virus known to be a causative agent in the pathogenesis of certain leukemias and lymphomas.

Epstein-Barr Virus (EBV)

A virus associated with the etiology of certain lymphomas.

t(8,14)

A specific chromosomal translocation associated with Burkitt’s lymphoma.

Acute lymphoblastic leukemia (ALL)

A type of leukemia characterized by a rapid increase in immature lymphoid cells.

Acute myelogenous leukemia (AML)

A type of leukemia involving rapid growth of myeloid precursor cells.

Chronic myelogenous leukemia (CML)

A slow-growing leukemia of the myeloid lineage often associated with the Philadelphia chromosome.

Chronic lymphocytic leukemia (CLL)

A slow-growing leukemia characterized by an excess of mature-appearing but dysfunctional lymphocytes.

Multiple Myeloma

A malignant disease of plasma cells in the bone marrow, often causing lytic bone lesions and hypercalcemia.

Lytic lesions

Punched-out holes in the bone caused by the proliferation of malignant plasma cells in multiple myeloma.

Intrinsic pathway

The coagulation cascade pathway involving factors XII, XI, IX, and VIII, measured by aPTT.

Extrinsic pathway

The coagulation cascade pathway involving tissue factor and factor VII, measured by PT.

Factor VIII

The specific clotting factor that is deficient in Hemophilia A.

Factor IX

The specific clotting factor that is deficient in Hemophilia B.

Hypersplenism

A condition leading to the increased removal and destruction of platelets in the spleen.

Disseminated intravascular coagulation (DIC)

A complex disorder involving the excessive consumption of clotting factors and platelets, leading to both thrombi and bleeding.

Thrombasthenia

A congenital disorder characterized by defective platelet function.

Hemostasis

The process involving vascular factors, platelet factors, and coagulation factors to maintain blood in a fluid, clot-free state or to stop bleeding.

Fibrinolysis

The enzymatic breakdown of fibrin in blood clots, primarily mediated by plasmin.

Thrombin

The enzyme generated in the common pathway that converts fibrinogen (Factor I) into a fibrin clot.

Lymphopenia

A reduction in the number of lymphocytes in the peripheral blood.

Lymphocytosis

An increase in the number of lymphocytes in the peripheral blood.

Stroma

The supportive framework of the bone marrow where hematopoietic stem cells reside.

What is the composition of peripheral blood?

Peripheral blood consists of plasma (about 55% of blood volume), which contains water, electrolytes, proteins, hormones, and waste products, and formed elements (about 45% of blood volume), including erythrocytes (red blood cells), leukocytes (white blood cells), and thrombocytes (platelets).

What is anemia?

Anemia is a reduction of blood oxygen carrying capacity, often associated with abnormal hemoglobin, reduced red blood cell count, or structural red blood cell abnormalities.

What are the three major forms of anemia?

1. Iron Deficiency Anemia: Caused by insufficient iron leading to decreased hemoglobin production.

2. Megaloblastic Anemia: Resulting from deficiencies in Vitamin $B_{12}$ or folic acid, affecting red blood cell maturation.

3. Aplastic Anemia: Caused by bone marrow failure and decreased hematopoiesis, leading to reduced blood cell production.

What are the causes of Iron Deficiency Anemia?

Iron Deficiency Anemia can be caused by insufficient dietary iron intake, blood loss (e.g., menstruation, gastrointestinal bleeding), or increased iron requirements during growth and pregnancy.

What are the typical findings of Iron Deficiency Anemia?

Typical findings include microcytic and hypochromic red blood cells, low serum ferritin, low hemoglobin levels, and an increased Total Iron Binding Capacity (TIBC).

What are the causes of Pernicious Anemia?

Pernicious Anemia is mainly caused by a deficiency of intrinsic factor due to autoimmune gastritis, leading to an inability to absorb Vitamin $B\_{12}$ from the gastrointestinal tract.

What are the typical findings of Pernicious Anemia?

Typical findings include macrocytic red blood cells, high levels of serum homocysteine and methylmalonic acid, and low Vitamin $B\_{12}$ levels.

What are the three forms of hereditary anemia?

1. Sickle Cell Anemia: Caused by a genetic mutation leading to hemoglobin polymerization, resulting in abnormal sickle-shaped red blood cells.

2. Thalassemia: A group of genetic disorders characterized by imbalanced globin chain synthesis, leading to ineffective erythropoiesis and hemolytic anemia.

3. Hereditary Spherocytosis: Caused by defects in red blood cell membrane proteins, leading to the formation of spherocytes and increased hemolysis.

Discuss the pathogenesis of Sickle Cell Anemia.

In Sickle Cell Anemia, a single nucleotide mutation in the HBB gene leads to the production of abnormal hemoglobin (HbS). Under low oxygen conditions, HbS polymerizes, causing red blood cells to deform into a sickle shape, which obstructs blood flow, leading to pain and organ damage due to vaso-occlusive crises.

Discuss the pathogenesis of Thalassemia.

Thalassemia results from mutations affecting the production of alpha or beta globin chains. A reduced production of one globin chain results in imbalanced hemoglobin synthesis, leading to microcytic anemia, increased red blood cell destruction, and ineffective erythropoiesis.

Discuss the pathogenesis of Hereditary Spherocytosis.

Hereditary Spherocytosis is caused by mutations in genes coding for proteins involved in red blood cell membrane integrity, such as ankyrin or spectrin. This leads to a weakened membrane and causes red blood cells to adopt a spherical shape, making them more prone to hemolysis, especially in the spleen.

What is intrinsic hemolytic anemia?

Intrinsic hemolytic anemia is caused by defects within the red blood cells themselves due to genetic abnormalities, leading to their premature destruction. Examples include sickle cell anemia, thalassemia, and hereditary spherocytosis.

What is extrinsic hemolytic anemia?

Extrinsic hemolytic anemia is caused by factors outside the red blood cells that lead to their destruction. This can result from autoimmune disorders, infections, or mechanical factors such as prosthetic heart valves.

What are the main causes of intrinsic hemolytic anemia?

Main causes include:

• Genetic defects: Sickle cell anemia, thalassemia, hereditary spherocytosis.

• Membrane defects: Abnormalities affecting red blood cell shape and survival.

• Enzyme deficiencies: Such as G6PD deficiency, leading to red blood cell vulnerability.

What are the main causes of extrinsic hemolytic anemia?

Main causes include:

• Immune-mediated destruction: Autoimmune hemolytic anemias caused by antibodies targeting red blood cells.

• Infections: Such as malaria, where parasites invade red blood cells.

• Mechanical destruction: Caused by conditions like disseminated intravascular coagulation (DIC) or prosthetic heart valves.

What are common laboratory findings in intrinsic hemolytic anemia?

Common findings include:

• Reticulocytosis: Increased reticulocyte count as the bone marrow responds to anemia.

• Positive direct Coombs test: In autoimmune cases.

• Decreased haptoglobin: Reflecting hemoglobin release into circulation.

What are common laboratory findings in extrinsic hemolytic anemia?

Common findings include:

• Reticulocytosis: Due to increased compensatory erythropoiesis.

• Increased lactate dehydrogenase (LDH): From cell breakdown.

• Positive Coombs test: If autoimmune hemolysis is involved.

What are the possible causes of Aplastic Anemia?

Aplastic Anemia can be caused by:

• Autoimmune disorders: Such as systemic lupus erythematosus (SLE) or rheumatoid arthritis.

• Exposure to toxins: Chemicals like benzene or drugs (e.g., chloramphenicol).

• Viral infections: Infections such as hepatitis, Epstein-Barr virus (EBV), or human immunodeficiency virus (HIV).

• Genetic conditions: Disorders like Fanconi anemia or dyskeratosis congenita.

What are the associated bone marrow biopsy findings in Aplastic Anemia?

Bone marrow biopsy in Aplastic Anemia typically shows:

• Hypocellular marrow: A reduction in hematopoietic cells, leading to increased fatty infiltration.

• Lack of hematopoietic stem cells: Decreased numbers of red blood cell, white blood cell, and platelet precursors.

• Presence of normal stroma: The supportive tissue appears intact but lacks cellularity.

What is Polycythemia Vera?

Polycythemia Vera is a primary polycythemia characterized by atypical hematopoietic cell precursors and decreased erythropoietin. It results in an increase in red blood cell mass and can lead to complications like thrombosis.

What is Secondary Polycythemia?

Secondary Polycythemia is an increase in red blood cells caused by hypoxia (due to heart/lung disease or high altitude) or excess erythropoietin production from tumors or kidney diseases. It is a physiological response to increased oxygen demand.

What are the main differences between Polycythemia Vera and Secondary Polycythemia?

1. Cause:

   • Polycythemia Vera: A primary disorder of the bone marrow.

   • Secondary Polycythemia: A response to external factors (e.g., hypoxia).

2. Erythropoietin Levels:

   • Polycythemia Vera: Typically low.

   • Secondary Polycythemia: Usually high or normal depending on the cause.

3. Clinical Features:

   • Polycythemia Vera: May present with symptoms of hyperviscosity such as headaches, dizziness, and increased risk of thrombotic events.

   • Secondary Polycythemia: Symptoms related to underlying condition causing hypoxia.

What are the laboratory findings in Polycythemia Vera?

Laboratory findings in Polycythemia Vera typically include:

• Increased hemoglobin and hematocrit levels.

• Low serum erythropoietin.

• JAK2 V617F mutation presence in most cases.

What are the laboratory findings in Secondary Polycythemia?

Laboratory findings in Secondary Polycythemia typically include:

• Increased hemoglobin and hematocrit levels.

• High or normal serum erythropoietin levels depending on the underlying cause.

• Often associated with underlying conditions such as chronic hypoxia.

What is leukocytosis?

Leukocytosis is an increase in the total number of white blood cells (leukocytes) in the peripheral blood, often indicative of an underlying condition such as infection or inflammation.

What is leukopenia?

Leukopenia is a decrease in the number of white blood cells (leukocytes) in the peripheral blood, which can increase the risk of infections and may result from various medical conditions or treatments.

What is lymphocytosis?

Lymphocytosis is an increase in the number of lymphocytes, a subtype of white blood cells, often seen in viral infections, lymphocytic leukemia, or chronic inflammatory conditions.

What is lymphopenia?

Lymphopenia is a decrease in the number of lymphocytes in the peripheral blood, which can result from conditions such as autoimmune diseases, infections, or treatment-related factors like chemotherapy.

What are possible causes of leukocytosis?

Possible causes of leukocytosis include:

• Infections: Bacterial, viral, or fungal infections.
• Inflammation: Conditions such as rheumatoid arthritis or inflammatory bowel disease.
• Stress: Physical or emotional stress can transiently elevate white blood cell counts.
• Leukemia: Malignancies involving white blood cells.