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