0 Cancer: an overview

0 التعليقات
Cancer: an overview

This proliferation leads to the formation of a tumor mass called . The tumor will gradually invade the organ in which it was born , altering its operation.
Cells can also escape from this mass, to disseminate in the body and lead to the formation of secondary tumors . This is called metastasis.
What is the difference between a healthy cell and a cancer cell ?
Healthy cells of the organism multiply controlled manner : they are divided when necessary and are not programmed to multiply a finite number of times . When they are broken too many times or when they show alterations that are not repairable , they die.
In contrast , the proliferation of cancer cells out of control . These cells can divide indefinitely. They , in addition, the ability to induce the formation of blood vessels that will supply them with oxygen and nutrients necessary for their multiplication . Some of them are also able to detach from the tissue from which they originally formed to migrate elsewhere in the body and lead to the formation of secondary tumors ( metastases).
How is a cancer?
Cancers arise from cells healthy and functional departure that have become abnormal due to the accumulation of alterations in their genetic (DNA). These alterations (or mutations) will lead to disruption , see inactivation systems that normally control cell division. The cell becomes capable of proliferating in an anarchic way to lead to the formation of a tumor.
Healthy cells have a system for detecting DNA damage and repair . When an abnormality is found, the cell division is temporarily stopped to allow repair. If the lesion is not repaired, the cell triggers a program that led to his death . Named this phenomenon is equated "apoptosis" to a cellular suicide.
Things get complicated when DNA lesions affecting regions themselves involved in these processes : if mutations occurred in genes required for anomaly detection or trigger programmed cell suicide , the cell will continue to divide anyway. This is the first step in the transformation of a normal cell into a cancer cell .
The accumulation of other abnormalities then lead the cell to lose its original function and acquire properties enabling it to give birth to a malignant tumor that can grow at the expense of surrounding healthy cells and migrate to other regions body .
How the cell's DNA can it be damaged?
The exposure to different substances , natural or artificial , say mutagens can lead to the appearance of lesions in the DNA of our cells. It may be industrial chemicals or chemicals such as those found in tobacco smoke , alcohol, ionizing radiation (radioactivity ) or solar radiation ( UV) , viruses ( HPV ) or bacteria ( Helicobacter pylori ) ...
And genetic predisposition to cancer ?
The transformation of a healthy cell into cancer cells involves the accumulation of multiple lesions in the DNA of cells . Some people are born with one or more lesions already present in their genetic heritage, often sent by their parents. These people were more important than the general population to develop cancer because their cells transformation has already begun at the time of their birth risk. We are talking about genetic predisposition to cancer.




0 التعليقات:

إرسال تعليق

شات احلي حياة

شات احلي حياة 

متعة الدردشة والشات علي الانترنت
وادخل واتعرف علي صحاب جدد

Get a7la7aya chat group | Goto a7la7aya website
Copyright 2011 مدونة نجم و نجوم.
Blogger Template by d-negm.
Best Blogger Gadgets