Mechanism of Disease
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