Calories, water, sunlight, vitamin/minerals
A set of rules developed for establishing the relationship between a cause and a disease (4 total)
Koch's Postulate Rule 1
The agent must be present in every case of disease
Koch's Postulate Rule 2
The agent must not be found in cases of other diseases
Koch's Postulate Rule 3
The agent must reproduce the disease when introduced into experimental animals
Koch's Postulate Rule 4
The agent must be recoverable from experimentally infected animals
Causes of Disease
Primary, Secondary and Predisposing
Primary Cause of Disease
The principal factor
Secondary Cause of Disease
Supplemental or contributory factors
Predisposing Cause of Disease
Render the animal more susceptible to a specific disea without actually causing it
Factors Contributing to Disease
Degree of exposure and condition of animal/environment
Exposure to Disease Examples
Contaminants/Physical agents (radiation, poisons), dose dependent and infectous agents
Innate vs. acquired; greater exposure means greater chance defense mechanisms will fail; compromised individuals will have lowered resistance
What caused the disease
Sequence of event s that produce the lesions
Causes of Cellular Injury
Hypoxia, physical agents, chemical agents, drugs, infectious agents, immunologic reactions and genetic derangements
Can cause cell injury; inadequate blood oxygenation; loss of O2 carrying capacity
Can cause cell injury; examples are trauma, heat and cold
Can cause cell injury; examples are viruses, bacteria, fungi and parasites
Can cause cell injury; inflammation - responses to infections that cause collateral damage
Can cause cell injury; alterations in chromosome number, gene mutations
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