Errors in cell division


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Errors in cell division

  1. 1. Errors in Cell Division Cancer
  2. 2. Out of control cell division  What happens when a cell doesn’t destroy itself?  What happens when a cell doesn‘t stop dividing?
  3. 3. Terminology  Cancer: a group of diseases in which cells undergo uncontrolled division  Tumour: mass of cells that grow and divide without any obvious function in the body  Benign tumour: cells stay together having no effect on surrounding tissue other than physical crowding  Malignant tumour: cells interfere with the function of surrounding cells
  4. 4. Characteristics of Cancer Cells  Rapid cell division  Uses energy and resources of other cells  Does no useful work of its own  May undergo metastasis: cancer cells that break away from the original location and move through the blood stream to a secondary location Click on picture for animation
  5. 5. Cause of Cancer: Mutations  Genetic mutations in the parts of the DNA responsible for regulating the cell cycle  Loss of 1 or more cell cycle checkpoints
  6. 6. Results of Mutation  Cell spends less time in interphase  Continuous mitosis  Rapid cell division
  7. 7. Carcinogens  Environmental factors that cause cancer Types Examples Viral Hepatitis B (liver cancer) HPV (cervical cancer) Ionizing radiation Nuclear fallout X-rays Sun (skin cancer) Mutagenic chemicals Cigarette (lung cancer)
  8. 8. Diagnosing Cancer: Imaging technologies  Endoscopy  X-ray  Ultrasound  CT/CAT scan (computerized axial tomography)  MRI (magnetic resonance imaging)
  9. 9. Imaging Technology: Endoscopy  Fiber-optic cable delivers a camera with light into the body and send images to a screen  Visual identification of abnormalities  Sometimes forceps are at the end so that tissue can also be removed
  10. 10. Imaging Technology: Endoscopy
  11. 11. Imaging Technology: X-rays  Useful for bones and lungs  Disadvantage: X-rays can cause DNA damage  Think:  Why are x-rays especially damaging to rapidly dividing cells?  Who should avoid x-rays?
  12. 12. Imaging Technology: X-rays  Mammogram: specialized x-ray for imaging breast tissue
  13. 13. Imaging Technology: Ultrasound  Use high frequency sound waves to create an image  Useful for looking at soft tissue
  14. 14. Imaging Technology: Ultrasound 12 weeks Head Hands Heart
  15. 15. Imaging Technology: Ultrasound 26 weeks Head Mouth Eyes Eyes
  16. 16. Imaging Technology: CT scan  CT or CAT scan: computerized axial tomography  Uses x-ray technology  Many images are taken from different angles  Images are assembled by a computer to form a series (i.e. like a flip book) CT scan animation Brain tumor, 3D CT scan. In the 3D scan the brain is red, bone is blue and the tumour is green (on the top left)
  17. 17. Imaging Technology: CT scan
  18. 18. Imaging Technology: MRI  Magnetic resonance imaging  Uses radio waves and a strong magnetic field to created detailed images  Computer assembles the information into a 3- dimensional model
  19. 19. Imaging Technology: MRI
  20. 20. Diagnosing Cancer: Biopsy  A sample of tissue is removed and analyzed to determine what it is CT scan animation
  21. 21. Diagnosing Cancer: Biopsy CT scan animation
  22. 22. Diagnosing Cancer: Biopsy CT scan animation
  23. 23. Reducing Risk: Screening  Important for those with a family history of cancer  Does not prevent cancer but increase the chance of detecting it early to treat it  Examples: self-examination, blood tests etc.  Some common screening:  Breast exam for breast cancer  Pap smear for cervical cancer
  24. 24. Reducing Risk: Lifestyle Choice  Healthy diet  “super foods”  Reduce body fat  Not smoking
  25. 25. Cancer Treatments  Surgery: physical removal of tumour  Chemotherapy  Radiation therapy
  26. 26. Cancer Treatment: Surgery
  27. 27. Cancer Treatment: Chemotherapy  a combination of drugs that kill rapidly dividing cells  can also affect normal rapidly dividing cells (e.g. hair follicle, intestinal cells)
  28. 28. Cancer Treatment: Radiation Therapy  Using high energy radiation to kill cancer cells but can also damage normal cells