Compensatory growth is a type of regenerative growth that can take place a number of human organs after the organs are either damaged, removed, or cease to function. Additionally, increased functional demand can also stimulate this growth in tissues and organs. The growth can be a result of increased cell size (compensatory hypertrophy

Hypertrophy

Hypertrophy is the increase in the volume of an organ or tissue due to the enlargement of its component cells. It should be distinguished from hyperplasia, in which the cells remain approximately the same size but increase in number...

) or an increase in cell division

Cell division

Cell division is the process by which a parent cell divides into two or more daughter cells . Cell division is usually a small segment of a larger cell cycle. This type of cell division in eukaryotes is known as mitosis, and leaves the daughter cell capable of dividing again. The corresponding sort...

 (compensatory hyperplasia

Hyperplasia

Hyperplasia means increase in number of cells/proliferation of cells. It may result in the gross enlargement of an organ and the term is sometimes mixed with benign neoplasia/ benign tumor....

) or both. For instance, if one kidney

Kidney

The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...

 is surgically removed, the cells of other kidney divide at an increased rate. Eventually, the remaining kidney can grow until its mass approaches the combined mass of two kidneys. Along with the kidneys, compensatory growth has also been characterized in a number of other tissues and organs including:

• the adrenal glands
• the heart
• muscles
• the liver
• the lungs
• the pancreas (beta cells and acinar cells)
• the mammary gland
• the spleen (where bone marrow and lymphatic tissue undergo compensatory hypertrophy and assumes the spleen function during spleen injury)
• the testicles
• the thyroid gland

A large number of growth factor

Growth factor

A growth factor is a naturally occurring substance capable of stimulating cellular growth, proliferation and cellular differentiation. Usually it is a protein or a steroid hormone. Growth factors are important for regulating a variety of cellular processes....

s and hormone

Hormone

A hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In essence, it is a chemical messenger that transports a signal from one...

s are involved with compensatory growth, but the exact mechanism is not fully understood and probably varies between different organs. Nevertheless, angiogenic growth factors

Angiogenesis

Angiogenesis is the physiological process involving the growth of new blood vessels from pre-existing vessels. Though there has been some debate over terminology, vasculogenesis is the term used for spontaneous blood-vessel formation, and intussusception is the term for the formation of new blood...

 which control the growth of blood vessel

Blood vessel

The blood vessels are the part of the circulatory system that transports blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and...

s are particularly important because blood flow significantly determines the maximum growth of an organ.

Compensatory growth

Compensatory growth (organism)

Compensatory growth, also known as catch-up growth and compensatory gain, is an accelerated growth of an organism following a period of slowed growth, particularly as a result of nutrient deprivation. Oftentimes, the body weights of animals who experience nutritional restriction will over time...

may also refer to the accelerated growth following a period of slowed growth, particularly as a result of nutrient

Nutrient

A nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment. They are used to build and repair tissues, regulate body processes and are converted to and used as energy...

deprivation.