NSG 3800 Adult Health and 3850 Patho Lecture Notes 2026

Anemia Patho Deep Dive Friday, January 02, 2026 4:31 PM • Hematopoiesis is a two-stage process that involves mitotic division (proliferation) and maturation (differentiation). • Each type of blood cell has stem cells that undergo mitosis when stimulated by a specific biochemical signal, indicating that the number of circulating cells has decreased. • Medullary or bone marrow hematopoiesis continues throughout life and can be accelerated by several mechanisms, including: • (1) an increase in differentiation of daughter cells, (2) an increase in number of stem cells, and (3) conversion of yellow (fatty) bone marrow (which does not produce cells) to red marrow (which does produce cells). • Marrow conversion(making RBC) is stimulated by erythropoietin, which is the hormone from the kidney that stimulates erythrocyte production. • In adults, extramedullary hematopoiesis, or production of blood cells in tissue other than bone, is usually due to disease. • Red cell development from pluripotential stem cells in the bone marrow is stimulated by a hormone growth factor called erythropoietin. • Erythropoietin is secreted into the bloodstream by kidney cells in response to low oxygen tension in the blood. • Red cell production requires adequate amounts of several nutrients, particularly iron, vitamin B12, and folate. • Lack of intrinsic factor inhibits absorption of B12 from the small intestine and is a risk factor for anemia. • • Hemoglobin is the major component of red cells. Hemoglobin Hgb Male: 14-18 g/dL Female: 12-16 g/dL Pregnant: 11 g/dL Hematocrit HCT Male: 42-52% Female: 37-47% Pregnant: 33% • • • Red cells rely on glycolysis for energy production because they do not contain mitochondria. • As energy production declines because of red cell aging and loss of essential glycolytic enzymes, the cell swells, is trapped in the spleen, and is removed from the circulation. • Red cell degradation releases bilirubin, a toxic substance that is conjugated in the liver and excreted in urine and bile.