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THE CELL CYCLE
Fig. 7.6
CANCER
Fig. 7.9
Cell Cycle Control
Cells that are not directed by the cell cycle
control system tend to divide out of control
This can result in a benign tumor
(abnormal mass of essentially normal cells)
Can cause problems depending on where they
are located
Always remain at the original site in the body
Displaces normal tissue as it grows
What is Cancer?
Cancer cells have a have a faulty cell cycle,
divide out of control and demonstrate
bizarre behavior
Malignant tumor – lump that results from
the division of a cancer cell
Can spread into nearby tissue or other parts of
the body
Displaces normal tissue as it grows
Can spread into the circulatory system
Metastasis – spread of cancer cells from origin
Cancer cont.
 Cancers are named for where they originate
 4 categories
1. Carcinomas – originate in the external or internal
coverings of the body
 EX – skin or linings of the intestines
2. Sarcomas – arise in tissues that support the body
 EX – bone and muscle
3. Leukemia – cancer of the blood forming tissue
 EX – bone marrow
4. Lymphomas – cancer of the blood forming tissue
 EX – lymph nodes
Cancer Treatments
Surgery or another method to stop cells from dividing…
• Radiation Therapy –
 Cancer cells exposed to
high-energy radiation
to disrupt cell division
 Radiation can usually
destroy cancer cells
without harming too
many normal cells
 Can have bad side
effects
 EX – sterility if near
ovaries or testes
• Chemotherapy –
 Drugs that disrupt cell
division are administered
 Antimitotic drugs –
prevent cell division by
interfering with spindle
formation
 EX – taxol and vinblastine