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Encyclopedia > Hyperplasia

Hyperplasia (or "hypergenesis") is a general term referring to the proliferation of cells within an organ or tissue beyond that which is ordinarily seen in e.g. constantly dividing cells. Hyperplasia may result in the gross enlargement of an organ, the formation of a benign tumor, or may be visible only under a microscope. Hyperplasia is considered to be a physiological response to a specific stimulus, and the cells of a hyperplastic growth remain subject to normal regulatory control mechanisms. This stands in contrast to neoplasia (the process underlying cancer and some benign tumors), in which genetically abnormal cells proliferate in a non-physiological manner which is unresponsive to normal stimuli.[1] For malignant tumors specifically, see cancer. ... A thin section of lung tissue stained with hematoxylin and eosin. ... This article or section does not cite any references or sources. ... Neoplasia (new growth in Greek) is abnormal proliferation of cells in a tissue or organ. ... Cancer is a class of diseases or disorders characterized by uncontrolled division of cells and the ability of these to spread, either by direct growth into adjacent tissue through invasion, or by implantation into distant sites by metastasis (where cancer cells are transported through the bloodstream or lymphatic system). ... Look up Benign in Wiktionary, the free dictionary. ...


Causes

Hyperplasia may be due to any number of causes, including increased demand, chronic inflammatory response, hormonal dysfunctions, or compensation for damage or disease elsewhere. Hyperplasia may be harmless and occur on a particular tissue. An example of a normal hyperplastic response would be the growth and multiplication of milk-secreting glandular cells in the breast as a response to pregnancy, thus preparing for future breast feeding. Human submaxillary gland. ... For other uses, see Breast (disambiguation). ... This article is about human pregnancy in biological females. ... A breastfeeding infant Breastfeeding is the practice of a woman feeding an infant (or sometimes a toddler or a young child) with milk produced from her mammary glands, usually directly from the nipples. ...


Hyperplasia may also be induced artificially by injecting hormones such as IGF-1 and human growth hormone. Perhaps the most interesting and potent effect IGF has on the human body is its ability to cause hyperplasia, which is an actual splitting of cells. Hypertrophy, on the other hand, is what occurs during weight training and steroid use and is simply an increase in the size of muscle cells. With IGF use, one is able to cause this hyperplasia which actually increases the number of muscle cells present in the tissue. Weight training with or without anabolic steroid use enables these new cells to mature in size and strength. In addition, animal tests have shown that stretching a muscle can trigger hyperplasia though this phenomenon has yet to be confirmed in humans.[2] The insulin-like growth factors (IGFs) are polypeptides with high sequence similarity to insulin. ... Human growth hormone can refer to: For physiology of human growth hormone, see growth hormone. ... Bodybuilder Markus Rühl has marked hypertrophy of skeletal muscle. ... Crystal structure of human sex hormone-binding globulin, transporting 5-alpha-dihydrotestosterone. ...


Hyperplasia may also occur abnormally, and is associated with a variety of clinical diseases.


Examples in human biology and disease

Some of the more commonly-known clinical forms of hyperplasia, or conditions leading to hyperplasia, are:

  • Congenital adrenal hyperplasia
  • Endometrial hyperplasia - Hyperproliferation of the endometrium, usually in response to unopposed estrogen stimulation in the setting of polycystic ovary syndrome or exogenous administration of hormones. Atypical endometrial hyperplasia may represent an early neoplastic process which can lead to endometrial adenocarcinoma
  • Benign prostatic hyperplasia also known as prostate enlargement.
  • Hyperplasia of the breast - 'Hyperplastic' lesions of the breast include usual ductal hyperplasia, a focal expansion of the number of cells in a terminal breast duct, and atypical ductal hyperplasia, in which a more abnormal pattern of growth is seen, and which is associated with an increased risk of developing breast cancer. The biology of these lesions is the subject of dispute, with some authorities arguing that both of these lesions are the result of neoplasia, and that the application of the term 'hyperplasia' in this instance is "inaccurate".[3]
  • Focal epithelial hyperplasia (also known as Heck's disease) - This is a wart-like growth in the mucous tissues of the mouth or, rarely, throat that is caused by certain sub-types of the human papillomavirus (HPV). Heck's disease has not been known to cause cancer.
  • Sebaceous hyperplasia - In this condition, small yellowish growths develop on the skin, usually on the face. This condition is neither contagious nor dangerous.
  • Compensatory liver hyperplasia - The liver undergoes cellular division after acute injury, resulting in new cells that restore liver function back to baseline. Approximately 75% of the liver can be acutely damaged or resected with seemingly full regeneration through hepatocyte division, ie hyperplasia. This is the basis for living-donor liver transplants.

Congenital adrenal hyperplasia (CAH) refers to any of several autosomal recessive diseases resulting from defects in steps of the synthesis of cortisol from cholesterol by the adrenal glands. ... Estriol. ... Polycystic ovary syndrome (PCOS, also known clinically as Stein-Leventhal syndrome), is an endocrine disorder that affects approximately one in ten women. ... Neoplasia (new growth in Greek) is abnormal proliferation of cells in a tissue or organ. ... Endometrial cancer involves cancerous growth of the endometrium (lining of the uterus). ... For other uses of the acronym BPH, see BPH (disambiguation). ... For other uses, see Breast (disambiguation). ... Neoplasia (new growth in Greek) is abnormal proliferation of cells in a tissue or organ. ... HPV redirects here. ... Sebaceous hyperplasia is a disorder of the sebaceous glands in which they become enlarged. ... For the bird, see Liver bird. ... Sinusoid of a rat liver with fenestrated endothelial cells. ...

References

  1. ^ Ramzi Cotran, Vinay Kumar, Tucker Collins (1999). Robbins Pathologic Basis of Disease, Sixth Edition. W.B. Saunders. ISBN 072167335X. 
  2. ^ Antonio, J, et al. (1994) "Muscle fiber splitting in stretch-enlarged avian muscle". Medicine & Science in Sports & Exercise, 26:8, 973-7.
  3. ^ Tavassoli FA (2005). "Breast pathology: rationale for adopting the ductal intraepithelial neoplasia (DIN) classification". Nature clinical practice. Oncology 2 (3): 116-7. doi:10.1038/ncponc0109. PMID 16264885.
Thyroid cancer is cancer of the thyroid gland. ... Thyroid cancer is cancer of the thyroid gland. ... Adrenocortical carcinoma is a carcinoma of the cortex (outer layer) of the adrenal gland. ... A phaeochromocytoma (pheochromocytoma in the US) is a neuroendocrine tumor of the medulla of the adrenal glands originating in the chromaffin cells, which secretes excessive amounts of catecholamines, usually adrenaline and noradrenaline (epinephrine and norepinephrine in the US). ... Pituitary adenomas are tumors that occur in the pituitary gland, and account for about 10% of intracranial neoplasms. ... A tumor suppressor gene is a gene that reduces the probability that a cell in a multicellular organism will turn into a tumor cell. ... An oncogene is a modified gene that increases the malignancy of a tumor cell. ... The stage of a cancer is a descriptor (usually numbers I to IV) of how much the cancer has spread. ... In pathology, Grading is a measure of the progress of tumors. ... Cancers are caused by a series of mutations. ... Look up carcinogen in Wiktionary, the free dictionary. ... Cancer research is research into cancer in order to identify causes and develop strategies for prevention, diagnosis, treatments and cure. ... A paraneoplastic phenomenon is a disease or symptom that is the consequence of the presence of cancer in the body, but is not due to the local presence of cancer cells. ... This is a list of terms related to oncology. ...

  Results from FactBites:
 
Understanding Cancer Series: Cancer - National Cancer Institute (118 words)
Nonetheless, cell structure and the orderly arrangement of cells within the tissue remain normal, and the process of hyperplasia is potentially reversible.
Hyperplasia can be a normal tissue response to an irritating stimulus.
An example of hyperplasia is a callus that may form on your hand when you first learn to swing a tennis racket or a golf club.
Hyperplasia - Wikipedia, the free encyclopedia (696 words)
Hyperplasia (or "hypergenesis") is a general term for an increase in the number of the cells of an organ or tissue causing it to increase in size.
Hyperplasia may be harmless and occur as a result of increased demand on a particular tissue.
Hyperplasia may also be induced artifically by injecting hormones such as IGF-1 and human growth hormone Perhaps the most interesting and potent effect IGF has on the human body is its ability to cause hyperplasia, which is an actual splitting of cells.
  More results at FactBites »

 
 

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