Aim: How can mitosis lead to a disruption in homeostasis?

I. What happens if mitosis stops? Aging Cancer Death

Cancer: Approximately 200 types Prostate cancer Breast cancer Lung cancer Skin cancer Can you think of others?

Healthy cells Grow, divide, and replace themselves during the process of mitosis. Each mitotic division leads to the development of 2 NEW healthy cells.

Abnormal cell division: Sometimes, normal cells lose their ability to limit and direct their growth. They divide and grow too rapidly and out of control.

What happens if cells are unable to regulate the cell cycle? *Cancer is a disease that is caused by loss of control of the cell cycle. *Cells continue to divide uncontrollably.

What is the result of uncontrollable mitosis? Cancer: Too many cells Abnormal Shape Abnormal function Starve the body’s other cells

Cancer… Tumors (lumps or masses of cancerous cells) will form as a result of this uncontrolled cell division. Types of tumors: a. malignant- spread = dangerous b. benign- can’t spread = safe

VII. Metastasis: *the spreading of cancer cells to other parts of the body to form new tumors. *How do they spread? By using the circulatory system and lymph nodes.

VIII. What causes cancer? Damage to the cells DNA from: Poor Diet Certain Pathogens (Viruses) Genetics UV Radiation (Sun) Drugs (Tobacco) Mutations - to genes, the cell's instructions for making the proteins it needs to survive, grow and multiply. Ultraviolet radiation Viruses Usually cancer is not inherited Carcinogens: chemicals A third of all cancers in the UK are linked to diet. Some types of food increase your risk, while others seem to have a protective effect. For example, a diet low in saturated fat, alcohol and red meat and high in fiber, fruit and vegetables can reduce your risk of some cancers, such as breast and colon cancer. Fruit and vegetables contain natural chemicals, antioxidants, that mop up free radicals: chemicals that can damage genes. Usually cancer is not inherited, even in families with several people affected, since it is a common disease. However, some people are born with an increased risk of cancer, because they inherit an altered gene important for cell growth or for repair of damaged DNA, for example. Scientists have already identified some of the genes that predispose to breast and colon cancer. There are likely to be others.

Anatomy of a Cigarette Smoking causes a third of all cases of cancer Cigarette smoke contains 3000 different chemicals, some of which are carcinogens. Some people have a lower risk of developing lung cancer. Their cells may be more efficient at repairing the gene damage caused by the carcinogens.

Lung Cancer: Healthy Lung Cancerous Lung

Melanoma: a type of cancer that begins in the melanocytes. Melanocytes are skin cells that produce melanin, the pigment that gives skin its color.

Melanomas have the following characteristics (ABCD rule) A: Asymmetry; the two sides of the pigmented area do not match B: Border is irregular and exhibits indentations C: Color (pigmented area) is black, brown, tan, and sometimes red or blue D: Diameter is larger than 6 mm (size of a pencil eraser)

Treatments: Surgery: physical removal of the malignant tumor Certain body tissues, such as breast and prostate, require hormones to develop. When cancer originates in these tissues, it responds to hormones. This means that the cancer responds to hormonal manipulation, which includes the administration of hormones, the withdrawal of hormones, or interference with hormone function. For example, by using chemicals that block the action of these hormones, it is possible to slow down, or even stop, the growth of cancer cells

Radiation Therapy: disrupts cell division

Chemotherapy: drugs that prevent cell division by interfering with mitosis

X. Prevention: *Don’t Smoke *Wear Sunscreen *Regular check-ups