Intro to Clinical Medicine | 2025/2026 | 50+ Questions | Hematopoiesis, Anemia, Polycythemia, B12 Deficiency

This document provides a detailed and updated review of over 50 exam-style questions with 100% verified correct answers, intended for Intro to Clinical Medicine Exam 1 in the 2025/2026 academic year. It delivers essential foundational knowledge for medical learners, focusing on blood cell formation, diagnostic markers, and clinical consequences of hematologic disorders. The content begins with a structured explanation of hematopoiesis, tracing the origin of blood cells from pluripotent stem cells in the bone marrow to differentiated myeloid and lymphoid lineages. Students are guided through developmental locations from fetal life (yolk sac, spleen) to adult sites like the axial skeleton, as well as the roles of RBCs, platelets, and WBCs. Key disorders are addressed with clarity: Aplastic anemia: its causes, clinical features (fatigue, infections, bleeding), pancytopenia, bone marrow findings (hypocellularity), and treatment options including immunosuppressants, transfusions, and bone marrow transplant. Polycythemia vera: a myeloproliferative disorder causing elevated RBC counts, thrombotic risks (CVA, MI), hypercellular marrow, and first-line treatments such as phlebotomy and aspirin. Anemia: classifications include microcytic (e.g., iron deficiency, lead poisoning), macrocytic (e.g., B12 or folate deficiency), and normocytic types. Diagnostic markers like reticulocyte count, TIBC, ferritin, transferrin, and homocysteine are used to assess etiology and severity. Vitamin B12 (cobalamin) deficiency and pernicious anemia are highlighted with their neurologic implications, Schilling test interpretation, and associated lab values. Additionally, this guide emphasizes clinical integration through pathophysiologic mechanisms, lab interpretation, and high-yield associations—making it ideal for multiple-choice test prep and foundational clinical reasoning. Best suited for: Medical students (MD/DO) in preclinical or clinical years PA and NP students in early systems-based or hematology modules Nursing students reviewing blood disorders or preparing for pathophysiology exams Anyone preparing for NBME-style exams, USMLE Step 1/2, or internal assessments Keywords: hematopoiesis, pluripotent stem cells, aplastic anemia, pancytopenia, reticulocyte count, polycythemia vera, phlebotomy, thrombotic risk, anemia types, microcytic anemia, macrocytic anemia, iron deficiency, B12 deficiency, cobalamin, homocysteine, Schilling test, transferrin, ferritin, hypovolemia, erythropoiesis, intrinsic factor