Sunday, 13 December 2015

CANCER

CANCER



  1. Cancer is a tumour.
  2. It is an abnormal growth or enlargement of tissue.
  3.  It has no co-ordination with normal tissue.
  4. It is an independent,autonomus,uncontrolled growth of a tissue containing a mass of abnormal cells.
  5.  A tumour serves no useful purpose but is harmful as it grows at the expense of the host like a parasite.
  6. Cancer now cause the second largest no.of deaths in most countries.
  7. There is no cure for cancer.


Types of tumour:


  1.  The tumour is two types, namely benign tumour and malignant tumour.


Benign tumour:


  1. The benign tumour remains fixed in the place of origin.
  2. It will not spread from one place to other.
  3. It can be cured by surgically removing the tissue.


Malignant tumour:


  1. It spread from one place to another through circulation and invasion.
  2. The spreading of tumour from one place to another is called metastasis.


Characteristics of Cancer:


  1. A tumour arises from an existing tissue or cells of the body.
  2. The growth of tumour is autonomous i.e. it follows
  3. its own laws of growth, it is not regulated by those governing the tissue from
  4. which or in which it grows.
  5. The tumour cells are undifferntiated and anaplastic in nature.
  6. Anaplasia refers to the reversion of differentiated cells into
  7. undifferentiated or embryonic cells.
  8. They have a greater potentially for growth and multiplication.
  9. They carry out none of the function of normal adult cells.
  10. They have large and irregular nuclei.
  11. They lose their contact inhibition.