MLT GlobeHematology: Hematopoiesis & general hematology
38 Hematology MCQs on Hematopoiesis & general hematology with answers and explanations.
Which statement about reticulocytes in a healthy adult is FALSE?
Normal reticulocytes are roughly 0.5–2.5% of red cells; 10% would indicate marked marrow response. They lack a nucleus but retain RNA, visible with supravital stains.
How long does a normal red cell survive in the circulation?
Normal erythrocytes survive about 120 days before splenic macrophages remove them. Shortened survival defines hemolysis.
In chronic hemolysis or marrow fibrosis, which organ most commonly resumes blood cell production outside the marrow?
Extramedullary hematopoiesis occurs mainly in the liver and spleen, the fetal sites of blood formation, causing hepatosplenomegaly.
In an adult, which type of bone marrow actively produces blood cells?
Red marrow is hematopoietically active; yellow marrow is mainly fat but can revert under stress. Gelatinous change reflects starvation, not activity.
Around the middle of fetal life, which organ is the main site of blood cell production?
The hepatic phase dominates from about the second to sixth fetal month, before the marrow takes over late in gestation.
Which is the earliest morphologically recognizable cell in the granulocyte series?
Granulocyte maturation proceeds from myeloblast to promyelocyte, myelocyte, metamyelocyte, band and segmented cell.
Which is the last nucleated stage before the nucleus is extruded in red cell development?
The sequence is pronormoblast, basophilic, polychromatic and orthochromatic normoblast; the orthochromatic cell then extrudes its nucleus to become a reticulocyte.
When monocytes leave the blood and settle in tissues, what do they become?
Monocytes mature into tissue macrophages that phagocytose and present antigen. Monoblasts are marrow precursors; mast cells come from a separate progenitor.
Histologically, blood is classified as which basic tissue type?
Blood is a specialized connective tissue: cells suspended in a fluid extracellular matrix (plasma), and derived from mesenchyme.
Which hormone, made mainly by the kidney, stimulates red cell production in the bone marrow?
Peritubular kidney cells release erythropoietin in response to hypoxia, stimulating erythroid progenitors. Thrombopoietin, made in the liver, drives platelet production.
Which feature distinguishes a mature circulating red cell from a leukocyte?
Normoblasts extrude their nucleus in the marrow, so mature erythrocytes are anucleate. Adult red cells are made in marrow, not the spleen; phagocytosis and plug formation belong to leukocytes and platelets.
Production of granulocytes and monocytes in the bone marrow is specifically termed:
Myelopoiesis covers granulocyte and monocyte formation from myeloid progenitors. Leukopoiesis is the broader term for all white cell production, including lymphopoiesis.
Many red cell blood group antigens are membrane proteins carrying carbohydrate chains. Such proteins are called:
Glycoproteins such as glycophorins and band 3 dominate membrane proteins and carry antigens like MN. Lipoproteins transport lipids in plasma.
Normal red cells survive in the circulation for approximately:
Aged red cells are removed mainly by splenic macrophages after about 120 days. Shortened survival defines hemolysis.
In a healthy adult, active hematopoiesis is found mainly in:
After childhood, red marrow retracts to the axial skeleton and proximal femur and humerus. Liver and spleen are fetal sites; the yolk sac is embryonic.
The normal adult spleen weighs approximately:
A normal spleen weighs about 150–250 g and is not palpable. It must enlarge substantially, commonly to about twice normal size, before it can be felt below the costal margin.
Which feature is NOT an adaptation that helps red cells carry gases and pass through capillaries?
Mature red cells lack mitochondria and rely on glycolysis, so they do not consume the oxygen they carry. Losing the nucleus, a biconcave shape and flexibility aid gas exchange and passage.
Fever and acidosis move the oxygen dissociation curve to the right. What does this mean?
A right shift (higher P50) reflects lower oxygen affinity, aiding delivery; causes include raised CO2, H+, temperature and 2,3-BPG. A left shift, as with HbF, means tighter binding.
Which feature of normal mature red cells most directly limits their lifespan to about 120 days?
Without a nucleus or ribosomes, red cells cannot replace aging enzymes and membrane proteins, so they gradually lose deformability and are removed by the spleen.
Which erythroid precursor has cytoplasm that stains mostly pink-orange due to near-complete hemoglobinization?
As hemoglobin accumulates and RNA falls, cytoplasm shifts from deep blue to grey to pink-orange. The orthochromatic stage is the most hemoglobinized nucleated precursor.