NON-INFECTIOUS DISEASES :
- These diseases cannot be transmitted from one person to another and not caused by pathogens.
CANCER:
- it can be defined as an uncontrolled abnormal
growth or proliferation of cells without any differentiation.
(1) in our body, cell growth and differentiation is highly controlled and regulated.
(2)the cancer cells divide repeatedly with
And controlled cell divisions. They do not require
extracellular growth factors. New cancer cells are known as NEOPLASTIC CELLS.
(3) cancer cells have lost the property of contact
inhibition shown by normal cells in which contact
With other cells inhibit their uncontrolled growth.
The repeated division of cancerous cells, form a large mass of cells called tumours.
(4) cancer cells move from tumour to new sites
through blood and form secondary tumour.
This invasion of cancer cells from one part to other parts by the body fluids is called Metastasis.
(5) Tumours are of two types
*BENIGN TUMOUR : it is non-cancerous
-it does not show metastasis.
-growth stops after reaching a certain size.
-less fatal.
*MALIGNANT TUMOUR: it is cancerous
-it shows metastasis.
- growth occurs indefinitely.
-highly fatal.
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