Hypertrophy
Some cells like adipocytes (fat cells) get larger by expanding outward while filling up with more lipid contents, while myocytes (muscle cells) can fuse with other myocytes to form huge myotube cells. Organs or tissues can grow larger due to the enlargement of their component cells. One of the most common and visible forms of normal, organ hypertrophy occurs in skeletal muscles in response to strength training or bodybuilding.