| Cancer - Cells Gone Bad |
When cells die they generally die a quiet and dignified death. They take
down all of the inner framework that holds them together and quietly devour
all of their components. Every day billions of your cells die for your benefit
and billions of others clean up the mess. Cells can also die violently (when
infected, for instance), but mostly they die because they are told to by their
DNA or by other cells.
down all of the inner framework that holds them together and quietly devour
all of their components. Every day billions of your cells die for your benefit
and billions of others clean up the mess. Cells can also die violently (when
infected, for instance), but mostly they die because they are told to by their
DNA or by other cells.
Occasionally a cell fails to
die in the normal manner
and instead begins to
divide and multiply wildly.
We call the result cancer.
Cancer cells are really just
confused cells. Cells make
this mistake regularly, but
the body can usually deal
with it. It is only very rarely
that the process spirals out
of control requiring medical
treatment.
die in the normal manner
and instead begins to
divide and multiply wildly.
We call the result cancer.
Cancer cells are really just
confused cells. Cells make
this mistake regularly, but
the body can usually deal
with it. It is only very rarely
that the process spirals out
of control requiring medical
treatment.
| MRI image cross-sections of a brain with a benign tumour. |
| from: www.bio.davidson.edu/courses/Bio111/tumor.html |
Tumours are generally divided into two main categories.
The first category, benign tumours, are strictly local affairs.
Benign tumours grow within an outer capsule, tend to grow
slowly, and don’t infect neighbouring cells outside of the
capsule. In fact, the only way benign tumours can usually
hurt us is if they aren’t removed and grow so large that they
compress vital organs.
The first category, benign tumours, are strictly local affairs.
Benign tumours grow within an outer capsule, tend to grow
slowly, and don’t infect neighbouring cells outside of the
capsule. In fact, the only way benign tumours can usually
hurt us is if they aren’t removed and grow so large that they
compress vital organs.
In contrast, malignant cancers (what we generally just
refer to as ‘cancer’) aren’t held within a capsule and grow
much faster than benign tumours. Malignant cancer cells
invade their surroundings rather than pushing them aside.
Malignant cells can also break away from the main
cancerous mass and travel throughout the body by way of
the blood or lymph systems to infect other body organs.
This capability to move throughout the body, called
metastasis, distinguishes cancer cells from the cells of
benign tumours. Cancer cells consume an exceptional
amount of the body’s nutrients, leading to loss of weight
and tissue wasting that contribute to death.
refer to as ‘cancer’) aren’t held within a capsule and grow
much faster than benign tumours. Malignant cancer cells
invade their surroundings rather than pushing them aside.
Malignant cells can also break away from the main
cancerous mass and travel throughout the body by way of
the blood or lymph systems to infect other body organs.
This capability to move throughout the body, called
metastasis, distinguishes cancer cells from the cells of
benign tumours. Cancer cells consume an exceptional
amount of the body’s nutrients, leading to loss of weight
and tissue wasting that contribute to death.
Almost half of all Australians will
develop some form of cancer in their
lifetime and a fifth of us will die from
it. Cancer can arise in almost any
cell type, but the most common
cancers originate in the skin, lung,
colon, breast, male prostate gland,
and urinary bladder.
develop some form of cancer in their
lifetime and a fifth of us will die from
it. Cancer can arise in almost any
cell type, but the most common
cancers originate in the skin, lung,
colon, breast, male prostate gland,
and urinary bladder.
Once diagnosed, most cancers are removed surgically if possible. To destroy
metastasised cells surgery is commonly followed by radiation therapy (X-ray
radiation and/or treatment with radioisotopes) and chemotherapy (treatment with
drugs made to kill cells). Anticancer drugs have unpleasant side effects because
most target all rapidly dividing cells, including normal ones. The side effects include
nausea, vomiting, and loss of hair.
metastasised cells surgery is commonly followed by radiation therapy (X-ray
radiation and/or treatment with radioisotopes) and chemotherapy (treatment with
drugs made to kill cells). Anticancer drugs have unpleasant side effects because
most target all rapidly dividing cells, including normal ones. The side effects include
nausea, vomiting, and loss of hair.
Treatment cures about half of all cases of malignant cancers. However, some
cancers have very low survival rates. These include cancers of the lungs, digestive
organs, and ovaries.
cancers have very low survival rates. These include cancers of the lungs, digestive
organs, and ovaries.
| Factual information contained on this page: Marieb, E. N. (1998). Human Anatomy & Physiology. Benjamin/Cummings Publishing. |
| Using the information on this page as well as the Cancer Council Australia's Prevention and Facts and Figures websites, complete these Check Your Knowledge tasks. |
| University of Canberra IT and Education Nick Moss & Greg Tompos October 2005 |
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(MALIGNANT CANCER)
| from: www.medicinenet.com/images/illustrations/lung_cancer_metastasis.jpg |
| from: www.healthsquare.com/fgwh/wh1c4001.jpg |
| from: Marieb, E. N. (1998). Human Anatomy & Physiology. Benjamin/Cummings Publishing. |