Increase in size of cells → increase in size of organ (no change in cell number) ● Mechanism: ○ Increased synthesis of structural proteins & organelles ○ Activation of growth factors (e.g., TGF-β, IGF-1) and signaling pathways (e.g., PI3K/AKT, G-protein–coupled receptors) ● Causes: ○ Increased workload (e.g., skeletal muscle in exercise) ○ Hormonal stimulation (e.g., uterus in pregnancy) Hypertrophy ● Morphology: ○ Enlarged cells with increased cytoplasmic volume ○ Increased nuclear size (DNA synthesis without cell division) ● Consequences: ○ Initially adaptive, improves function ○ Prolonged hypertrophy → functional decline, cell injury, organ failure Hypertrophy Physiological Hypertrophy Pathological Hypertrophy Normal adaptive response Occurs due to disease or abnormal stress Examples: Skeletal muscle enlargement in athletes Uterine smooth muscle hypertrophy during pregnancy (estrogen stimulation) Examples: Left ventricular hypertrophy in chronic hypertension Pyloric stenosis.. explain