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