MBI 111 Test 1 study guide

MBI 111 Test 1 study guide - Principles of Affection and...

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Principles of Affection and Disease Case 2 yr old, upper respirator infection for 2 weeks, hospitalized, dypheria, high mortality, uncommon in US, caused by a bacteria Definitions 1. Symbiosis: Organisms living together (3 forms) a. Commensalism: One organism benefits, other is unaffected i. Bird in a tree b. Mutualism: Both organisms benefit i. Fungi and algae together c. Parasitism: One benefits, other is harmed i. Human disease d. All disease agents are parasites e. Parasite= protist f. What would make a successful parasite? i. Difficult to get rid of ii. Well hidden iii. Easily spread (communicable, transmittal) iv. Agent that will harm host slowly or little at a time in order to last longer v. Adaptation vi. Agents multiply so quickly (make DNA, chance of mutation) vii. Most dangerous if can live outside of host 2. Trends: New disease agents are very severe, high mortality rates (Ebola). Over time it will become less severe 3. In disease events, usually parasitism is the cause: a. Host: organism that provides nutrients, protection, etc. to another organism b. Parasite: Organism that lives at the expense of (and may even harm) its host; parasite is usually smaller than host and is metabolically dependent on it
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4. Disease: An upset in the homeostasis (to maintain the steady state) of the host, resulting in observable changes a. Symptom: Subjective evidence of damage to host (headache, anorexia) (Don’t show on outside) b. Sign: Objective evidence of damage to the host (fever, rash, emesis) (can measure, see on outside) c. Infectious Disease: damage or toxicity in body caused by infectious agent (parasite) 5. Pathogen: Microorganism that is capable of causing disease 6. Virulence: Measure of pathogenicity: Ability to cause a disease. Virulent=pathogenic a. Virulent: Microbes that readily cause disease b. Attenuated: microbes with reduced ability to caused disease, some vaccines c. Avirulent: microbes that do not cause disease, in vaccines. Formerly a disease agent. A piece of the cell wall d. Opportunistic: microbes that normally are avirulent (normal microbiota), but may become virulent when given the opportunity. Organisms that technically don’t cause diseases but they could i. Ex) staff bacteria on hand, small cut infection Resident Flora (Normal Flora, Microflora) 1. Definition: Normal microorganisms that live in and on body. a. Includes bacteria, fungus, protists, possibly viruses and anthropods 2. Infection: Pathogenic microorganism penetrate host defenses, enter tissues, and multiply 3. Endogenous Infection: when normal flora enter site that was previously sterile (central nervous system-brain, spinal cord, kidneys kidney infection) Koch’s Postulates Established in 1875 while working with Bacillus anthracis (causes anthrax) Still used today to determine etiology (causation) of disease 1. Organism must be present in every case of the disease, but absent from healthy host 2. Organism must be isolated and grown in pure culture 3. Organism must cause the disease when used to inoculate new host
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4. Organism must be isolated from new host
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MBI 111 Test 1 study guide - Principles of Affection and...

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