Chapter 14 Flashcards
Principles of Disease and Epidemiology
Pathology
Scientific study of disease, concerning the cause of disease and the structural and functional changes brought about by disease and with their final effects on the body
Etiology
The study of the cause of disease
Pathogenesis
The manner in which disease develops
Infection
The invasion or colonization of the body by pathogenic microorganisms pr the presence of a microorganism in part of the body where it is not normally found. It can exist in the absence of detectable disease; no symptoms.
Disease
Occurs when an infection results in any change from a state of health. It’s an abnormal state. The body cannot perform all it’s normal functions. Part or all of the body is not properly adjusted.
Human Microbiome Project
Began in 2007 to analyze microbial communities called microbiomes that live on and in the body. With a goal of trying to determine the relationship between changes in human microbiome and human health and disease.
Normal microbiota
Normal flora; Microorganisms that establish more or less permanent residents (colonize) but do not produce disease under normal conditions.
Transient microbiota
Microorganisms that may be present for several days, weeks, or months and then disappear. They are not found throughout the entire human body but are localized in certain regions.
What are the factors that determine the distribution and composition of normal microbiota
Nutrients, physical and chemical factors, defenses of the host, and mechanical factors.
How do nutrients affect normal microbiota and where do they come from
Microbes can colonize only those body sites that can supply the appropriate nutrients. These nutrients maybe derived from secretory and excretory products of cells, substances in body fluids, dead cells, and foods in the gastrointestinal tract.
What are the physical and chemical factors that affect the growth of microbes and result in normal microbiota
Temperature, pH, available oxygen and carbon dioxide, salinity, and sunlight
What are mechanical forces that the human body uses against microbes
Mechanical forces such as chewing, the flow of saliva and digestive secretions, the flushing of urine during urination.
How does the human body’s protect itself against microbes
The human body has a variety of molecules and activated cells that kill microbes, inhibit their growth, prevent their adhesion to host cell surfaces and neutralize toxins that microbes produce.
Microbial antagonism
Also known as competitive exclusion. A manner in which normal microbiota can benefit the host by preventing the overgrowth of harmful micro organisms, involving competition among microbes.
How does microbial antagonism protect the host against colonization by potentially pathogenic microbes
Normal microbiota compete with pathogenic microbes for nutrients and they produce substances harmful to the invading microbes and affect conditions such as pH and available oxygen.
What is the relationship between the normal micro biota and the host called and what does it mean
Symbiosis. At least one organism is dependent on the other
Commenalism
Symbiotic relationship in which one of the organisms benefits and the other is unaffected
Mutualism
A type of symbiosis that benefits both organisms
Parasitism
A type of symbiosis where one organism benefits by deriving nutrients at the expense of the other.
How can a mutualistic organism become harmful? What’s an example
As long as it remains in it’s normal environment it is not infectious. Once it gets access to bbn other body sites it can become infectious. Example: E. coli in the large intestine is normal, if it gets into the urinary tract it can become infectious
Opportunistic pathogens
Microbes that do not ordinarily cause disease in their normal habitat in a healthy person but may do so in a different environment. Example: E. coli
Example of commensalism
Staphylococcus epidermidis on the skin
Example of mutualism, how
E coli in the large intestine. They synthesize Vit K and some B vit that are absorbed into the bloodstream and used by cells in the body. In exchange the large intestine provides nutrients used by baceria that allows for their survival
Other than competition among microbes, what is another factor in the cause of disease
Cooperation among microbes. Example: pathogens that cause periodontal disease and gingivitis have been found to have receptors, not for teeth, but for oral streptococci that colonize the teeth