8.3 - Control of Cell Cycle

1. 8.3 - Control of Cell Cycle • The speed of cell division varies with • tissue type and organism • Intestine lining----24 to 48 hours • Frog embryo------less than 60 minutes • Adult liver----------once a year 2. Cell division is still not completely understood

2. Cell Enzymes Control Cell Cycle Cancer – uncontrolled dividing of cells 1. Enzymes normally start and/or stop the cell cycle 2. Cancer results from cells: a. failing to produce enzymes that inhibit or stop the cell cycle b. producing too much of enzymes that continue cell division c. producing enzymes at the wrong time 3. Enzyme production is directed by cell DNA

3. Contact Inhibition -when cells stop dividing after they completely cover an area 1. Normal cells produce or secrete chemical signals that stop cell division and growth when cells come in contact each other 2. Cancer cells will ignore these signals and continue to grow and divide unchecked 3. Cancer cells can move from one organ/area to another spreading the cancer

4. Cancer – A mistake in the cell cycle Cancer can be caused by: • Random mutations or changes in one or more genes • in the DNA that control enzyme production. 2. Environmental factors. Ex. nicotine alcohol toxic chemicals metal pollutants UV radiation 3. Inherited potential for certain cancers 4. Viral infections

5. Cancer Growth 1. Cancer cells can grow slowly over many years (benign tumors). These are more easily treated. 2. Cancer can grow very rapidly and spread (metastasize) to other body tissues. This is also called a malignant tumor. Usually treated with a combination of surgery, radiation and/or chemotherapy Since cancer is “ of the body ” your white blood cells cannot protect you from the cancer.

6. Basal cell carcinoma is the most common form of skin cancer worldwide, accounting for 80% of all diagnosed skin cancer cases. Where it Occurs Basal cell carcinoma appears most often on sun-exposed areas, such as the as the face, scalp, ears, neck, chest, hands, back, and legs. Though rare, basal cell carcinoma can occur on skin that has been protected from the sun.

7. Warning Signs • Basal cell carcinoma can take several forms: • Small, translucent growth with rolled edges that may be • pigmented (brown) or have small blood vessels on • the surface • 2. Open sore that bleeds, heals, and then repeats the cycle • 3. Cluster of slow-growing, shiny pink or red lesions that are • slightly scaly and bleed easily • 4. Flat or slightly depressed lesion that feels hard to the • touch; may be white or yellow and have indistinct borders • 5. Waxy scar that is skin-colored, white, or yellow

8. Basal Cell Carcinoma This type of basal cell carcinoma is called sclerosing basal cell carcinoma, which typically appears as a thickened, skin-colored scar. This elderly patient has superficial basal cell carcinoma, a type of basal cell carcinoma that usually appears as multiple, slow-growing, shiny pink or red, slightly scaly lesions that most often develop on the trunk and shoulders.

9. Basal Cell Carcinoma

10. Squamous Cell Carcinoma:  about 16% of new skin cancer cases in the United States. Where Occurs- commonly found on sun-exposed areas of the body, however, it may occur anywhere even inside of the mouth, on a lip, or on genitals.Warning SignsSigns of squamous cell carcinoma include: Crusted or scaly area on the skin with a red, inflamed base Persistent, non-healing, ulcerated (skin not covering) bump or thickened skin on the lower lip Wart-like growth or plaque Sore that does not heal Red, scaly patches or bumps

11. This tumor developed rapidly over a six-month period on the patient’s scalp. This tumor appeared as a persistent, non-healing lesion on the patient’s lower lip.

14. The patient said that this lesion, which appears as a well-defined plaque, had been slowly growing for years. Advanced squamous cell carcinoma on the hands and forearms of an elderly patient.

15. Melanoma:  What it Looks Like While only 4% of diagnosed skin cancer is melanoma, melanoma is the most serious form of skin cancer because of its ability to spread. This is why it is so important to catch melanoma early when the cure rate with dermatological surgery is about 95%. Where OccursMelanoma can appear anywhere on the body — soles, palms, inside the mouth, genitalia, and underneath nails. However, it is most commonly found on the back, buttocks, legs, scalp, neck, and behind the ears.Warning signsMelanoma often develops in a pre-existing mole that begins to change or a new mole. It is estimated that 20% to 40% of melanomas arise from an atypical mole. This is why it is so important to be familiar with the moles on your body and perform regular self-examinations of your skin. When looking at moles, keep in mind the ABCDs of Melanoma Detection:

16. Asymmetry. If you could fold the lesion in two, • the two halves would not match. 2. Border. Melanomas often have uneven or blurred borders.

17. 3. Color. Melanoma typically is not one solid color; rather it contains mixed shads of tan, brown, and black.  It can also show traces of red, blue or white. 4. Diameter. While melanomas are usually greater than 6 millimeters (about the size of a pencil eraser), they can be smaller. If you notice a mole different from others, or which changes, itches, or bleeds even if it is smaller than 6 millimeters, you should see a dermatologist.

18. Melanomas

20. Lungs and Lung Cancer Healthy Lungs

21. Lungs with Cancer

22. Smoker’s Lungs

23. Mouth cancers