hypertrophy

all year i have been hearing the word "hypertrophy" being thrown around but never really understood what it meant. myocardial hypertrophy in simple terms is an enlarged heart. renal hypertrophy is an enlarged kidney. hypertrophy is when cells grow in size in response to a stressor. for example, when someone has uncontrolled high blood pressure for a long period of time, the heart muscle responds by enlarging. this enlargement happens because each cell grows bigger, not because more cells are present. similarly, when we work out, our skeletal muscles enlarge. we can feel a bulging calf on a runner not because they have developed more muscle cells but because each of their cells (and the organelles within the cells) have swelled so that they can work more efficiently. another example of this is when a person donates a kidney to someone in need of a transplant. their one remaining kidney hypertrophies to accommodate filtering all of the blood on its own. smart cells we have!

biceps hypertrophy in response to lifting weight