Hematopoiesis
What are the primary sites of hematopoiesis in the human body during different life stages
In the fetus, hematopoiesis occurs in the yolk sac, liver, and spleen. After birth, it primarily occurs in the bone marrow. In adults, hematopoiesis mainly takes place in the axial skeleton
What are the main types of white blood cells, and what are their primary functions?
The main types are neutrophils (phagocytosis of pathogens), lymphocytes (adaptive immune response), monocytes (differentiate into macrophages), eosinophils (combat parasitic infections), and basophils (involved in allergic reactions).
What are the key steps in the coagulation cascade?
The coagulation cascade involves vascular spasm, platelet plug formation, and the activation of clotting factors leading to the conversion of fibrinogen to fibrin, stabilizing the clot.
What are the common types of anemia, and how are they classified?
Common types include iron deficiency anemia, vitamin B12 deficiency anemia, folate deficiency anemia, and hemolytic anemia, classified based on their underlying causes and pathophysiology
What are the major blood groups, and how are they determined?
The major blood groups are A, B, AB, and O, determined by the presence or absence of specific antigens (A and B) on the surface of red blood cells.
Describe the process of erythropoiesis and the role of erythropoietin.
Erythropoiesis is the production of red blood cells (RBCs) from hematopoietic stem cells in the bone marrow. Erythropoietin, produced by the kidneys in response to low oxygen levels, stimulates the differentiation of progenitor cells into erythrocytes.
Describe the structure and function of red blood cells.
Red blood cells (erythrocytes) are biconcave discs that lack a nucleus and organelles. Their primary function is to transport oxygen from the lungs to tissues and carbon dioxide from tissues to the lungs.
Describe the differences between intrinsic and extrinsic pathways of coagulation.
The intrinsic pathway is activated by damage to blood vessels and involves factors present in the blood, while the extrinsic pathway is triggered by tissue factor released from damaged tissues.
What are the laboratory findings associated with iron deficiency anemia?
Laboratory findings typically include low hemoglobin and hematocrit, low serum ferritin, low serum iron, high total iron-binding capacity (TIBC), and microcytic, hypochromic red blood cells on a peripheral blood smear.
Describe the process of blood typing and crossmatching prior to transfusion.
Blood typing involves mixing a patient's blood with anti-A and anti-B antibodies to determine the blood group. Crossmatching tests the compatibility of donor and recipient blood by mixing them and observing for agglutination.
What are the key differences between myeloid and lymphoid lineages in hematopoiesis?
Myeloid lineage gives rise to red blood cells, platelets, and most white blood cells (e.g., neutrophils, eosinophils, basophils, monocytes). Lymphoid lineage produces lymphocytes (T cells, B cells, and natural killer cells).
What is the role of platelets in hemostasis?
Platelets adhere to damaged blood vessels, aggregate to form a temporary plug, and release substances that promote coagulation and vasoconstriction, contributing to hemostasis.
What role do platelets play in primary hemostasis?
Platelets adhere to exposed collagen at the injury site, become activated, and aggregate to form a temporary platelet plug, initiating the hemostatic process.
How do leukemias differ from lymphomas in terms of pathophysiology and clinical presentation?
Leukemias are characterized by the proliferation of abnormal hematopoietic cells in the bone marrow and peripheral blood, leading to cytopenias. Lymphomas involve the proliferation of lymphoid tissue, presenting as lymphadenopathy, splenomegaly, and systemic symptoms.
What are the risks associated with blood transfusions, and how can they be minimized?
Risks include transfusion reactions (e.g., hemolytic, allergic), infections, and transfusion-related acute lung injury (TRALI). Minimization strategies include careful blood typing, crossmatching, and using leukoreduced blood products.
How do stem cells differentiate into various blood cell types?
Hematopoietic stem cells undergo a series of differentiation steps influenced by growth factors and cytokines, leading to the formation of progenitor cells that further differentiate into specific blood cell types.
How do neutrophils respond to infection, and what is their lifespan?
Neutrophils migrate to sites of infection, where they phagocytize pathogens and release enzymes. Their lifespan is typically 5-7 days in circulation and shorter in tissues.
How does the body regulate coagulation to prevent excessive bleeding or thrombosis?
The body regulates coagulation through anticoagulant proteins (e.g., antithrombin, protein C), fibrinolysis (the breakdown of clots), and maintaining a balance between pro-coagulant and anti-coagulant factors.
What are the clinical features and laboratory findings of thrombocytopenia?
Clinical features may include easy bruising, petechiae, and prolonged bleeding. Laboratory findings typically show a low platelet count, and further tests may be needed to determine the underlying cause.
What is the role of antibodies in transfusion reactions?
Antibodies in the recipient's plasma can react with incompatible antigens on transfused red blood cells, leading to agglutination, hemolysis, and potentially severe transfusion reactions.
What factors can influence hematopoiesis, and how do they affect blood cell production?
Factors include hormones (e.g., erythropoietin), cytokines (e.g., interleukins), nutritional status (e.g., iron, vitamin B12, folate), and pathological conditions (e.g., inflammation, infection)
What are the differences between T cells and B cells in the immune response?
T cells are primarily involved in cell-mediated immunity, recognizing and destroying infected or cancerous cells, while B cells are responsible for humoral immunity, producing antibodies that neutralize pathogens.
What are the clinical implications of inherited coagulation disorders, such as hemophilia?
Inherited coagulation disorders can lead to excessive bleeding, easy bruising, and complications during surgery or trauma, requiring careful management and treatment.
How do hemolytic anemias differ in their mechanisms and laboratory findings?
Hemolytic anemias can be classified as intrinsic (e.g., hereditary spherocytosis, sickle cell disease) or extrinsic (e.g., autoimmune hemolytic anemia). Laboratory findings may include elevated indirect bilirubin, low haptoglobin, and reticulocytosis.
Describe the differences between whole blood, packed red blood cells, and plasma transfusions.
Whole blood contains all components of blood, including red cells, white cells, platelets, and plasma. Packed red blood cells (PRBCs) are concentrated red cells with most plasma removed, used primarily for anemia. Plasma transfusions provide clotting factors and are used in cases of coagulopathy or liver disease.
Whole blood contains all components of blood, including red cells, white cells, platelets, and plasma. Packed red blood cells (PRBCs) are concentrated red cells with most plasma removed, used primarily for anemia. Plasma transfusions provide clotting factors and are used in cases of coagulopathy or liver disease.