Increase in the size of the organ or tissue due to increase in the size of the cells

WHAT CAUSES HYPERTROPHY?

Due to increase in the functional demand/workload

1.PHYSIOLOGICAL

• Hypertrophy of skeletal muscles- Ex- bulging muscles of athletes
• Hypertrophy of the smooth muscles- Ex- growth of the the uterus during pregnancy from estrogenic stimulation

PATHOLOGICAL

• Hypertrophy of cardiac muscle – left ventricular hypertrophy or damaged valves ( aortic stenosis, mitral incompetence)
• Hypertrophy of smooth muscle– hypertrophy of the urinary bladder in response to urethral obstruction ( prostrate hyperplasia) and hyperplasia of the stomach due to pyloric stenosis .

Mechanism of hypertrophy –

It occurs due to synthesis of the cellular proteins .

Mechanism involved in the hypertrophy of cardiac muscle-

Physiological hypertrophy– Due to increase in the workload causes mechanical stretch of the myocardium.

Pathological hypertrophy– due to to growth factors and hypertrophy agonists-

1. Growth factors – TGF – beta, insulin growth factor ( IGF -1) , Fibroblast growth factor (FGF)

2. Hypertrophy agonists- alpha-adrenergic agonists , endothelin-I , angiotensin -II , Nitric oxide (NO) and bradykinin

Source – Harshmohan ( textbook of pathology) and Ramdas Nayak