Mechanism of Disease

Prevention and Control Prevent them from entering the body Pathogens can spread by:  Person to person contact - viruses  Environmental contact – food, water, soil  Opportunistic invasion – moist skin/fungus  Transmission by a vector- ex. Deer tick/lyme

Prevention  aseptic technique – kill/disable pathogens on surface before they can spread to others Examples: sterilization, disinfection, antisepsis, isolation  Avoiding contact with certain materials  Maintaining safe sanitation practices  Avoid changes in pH, moisture, temperature of skin and mucous membranes  Reduce number of vectors and reduce contact with vectors  Vaccine – dead or weakened pathogen given to stimulate immunity

Treatment Antibiotics – penicillin, streptomycin Synthetic antiviral agents – acyclovir, efavirenz

Tumors and Cancer Neoplasm = tumor = abnormal growth of cells  Benign remain localized, grow slow, cells well differentiated, cells stay together, often surrounded by dense tissue or capsule, usually not life threatening  Malignant – spread to other regions = CANCER Not encapsulated, do not stay in one place (metastasis), undifferentiated

3 types of benign tumors Epithelial tissue  Papilloma – fingerlike projections, wart  Adenoma – glandular  Nevus – small, pigmented tumors of the skin, mole Connective tissue  Lipoma – arise from adipose tissue  Osteoma – bone tissues  Chondroma – cartilage tissue

Malignant tumors Epithelial – called carcinomas  Melanoma – melanocytes  Adenocarcinoma – glandular epithelium Connective - called sarcomas  Lymphoma – lymphatic tissue  Osteosarcoma – bone tissue  Myeloma – bone marrow tumor  Fibrosarcoma – fibrous connective tissue

Miscellaneous tumors Adenofibroma – benign tumor from epithelial and connective tissues Neuroblastoma – malignant tumor of nerve tissue Cancers can further be classified by location (stomach, skin…)

Causes of Cancer Uncontrolled cell division Hyperplasia – too many cells Anaplasia – abnormal, undifferentiated tumor cells Not sure what causes abnormal cell division

Factors that play a role in abnormal cell division Genetic factors  Oncogenes – cancer genes, still researching  Predispositions  Basal cell carcinoma, breast cancer, neuroblastoma Carcinogens – chemicals that affect genetic activity  Mutagens (mutation makers) Age - Young – leukemia, older – colon cancer Environment – radiation, breathing asbestos Viruses – papilloma viruses – cervical cancer