Fig. 7.6 THE CELL CYCLE

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 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 Surgery or another method to stop cells from dividing…