Compensatory growth (organ) explained

Compensatory growth is a type of regenerative growth that can take place in a number of human organs after the organs are either damaged, removed, or cease to function.^[1] Additionally, increased functional demand can also stimulate this growth in tissues and organs.^[2] The growth can be a result of increased cell size (compensatory hypertrophy) or an increase in cell division (compensatory hyperplasia) or both.^[3] For instance, if one kidney is surgically removed, the cells of the other kidney divide at an increased rate.^[1] Eventually, the remaining kidney can grow until its mass approaches the combined mass of two kidneys.^[1] Along with the kidneys, compensatory growth has also been characterized in a number of other tissues and organs including:

• The adrenal glands^{[4] [5]}
• The heart^{[5] [6]}
• Muscles^[5]
• The liver^{[5] [7]}
• The lungs^[8]
• The pancreas (beta cells and acinar cells)^[7]
• The mammary glands^[5]
• The spleen (where bone marrow and lymphatic tissue undergo compensatory hypertrophy and assumes the spleen function during spleen injury)^[5]
• The testicles^[5]
• The thyroid gland^{[5] [9]}
• The turbinates of the nose

A large number of growth factors and hormones are involved with compensatory growth, but the exact mechanism is not fully understood and probably varies between different organs.^[1] Nevertheless, angiogenic growth factors which control the growth of blood vessels are particularly important because blood flow significantly determines the maximum growth of an organ.^[1]

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

See also

• Hyperplasia
• Hypertrophy
• Cellular adaptation

Notes and References

1. Book: Widmaier, E. P.. Raff, H.. Strang, K. T.. amp. Vander's Human Physiology: The Mechanisms Of Body Function. limited. 10th. McGraw-Hill Companies. Boston, Mass. 383. 2006. 978-0-07-282741-5.
2. Goss . R. . Kinetics of Compensatory Growth . The Quarterly Review of Biology . 40 . 123–146 . 1965 . 2 . 14338253 . 10.1086/404538. 19069765 .
3. Web site: compensatory growth (biology) -- Britannica Online Encyclopedia . 10 June 2011 .
4. Book: Swale Vincent. Internal secretion and the ductless glands. 10 June 2011. 1912. Arnold. 150.
5. Book: Francis Delafield. Theophil Mitchell Prudden. A text-book of pathology with an introductory section on post-mortem examinations and the methods of preserving and examining diseased tissues. 10 June 2011. 1907. William Wood and Company. 61–62.
6. Book: M. I. Gabriel Khan. Encyclopedia of heart diseases. 10 June 2011. 5 December 2005. Academic Press. 978-0-12-406061-6. 493–494.
7. Book: Anthony Atala. Principles of regenerative medicine. 10 June 2011. 2008. Academic Press. 978-0-12-369410-2. 101–102.
8. Rannels . D. . Role of physical forces in compensatory growth of the lung . The American Journal of Physiology . 257 . 4 Pt 1 . L179–L189 . 1989 . 10.1152/ajplung.1989.257.4.L179 . 2679138.
9. Book: Harold Clarence Ernst. The Journal of medical research. 10 June 2011. 1919. 199.