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20 Cards in this Set
- Front
- Back
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Viruses |
20-400mm, have no cellular structure no organelles or cells wall and involves a protein capsule contains nucleic acid Can only grow inside living cells Must use host to reproduce Cannot be cultured |
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Bacteria |
Small 0.5-2um prokaryotes with rigid cell walls capable of independent survival Mostly unicellular Can be motile and or rod like shaped or spherical Disease break down cells and eels ease toxins that interfere with cellular activity eg. Strep throat hurts a |
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Parasites |
A parasite is an organism that lives on or in a host organism and gets its food from or at the expense of its host. There are three main classes of parasites that can cause disease in humans: protozoa (eukaryotic and single celled) , helminths, and ectoparasites |
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Fungi |
Eukaryotic, uni or multi cellular The cell wall is present Produce spores which may be toxic Tina Capitis |
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Bacteria growth requirements |
Temp- 10-39 degrees Moisture- prefer moist, can survive in dry but need water for reproduction PH- 6-8 Food- carbon nitrogen and vitamins Oxygen- obligate aerobes and anaerobes |
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Gram positive vs negative |
Positive thicker cell walls will retain dye stains blue or purple Negative thinner cell wall will not retain due and stains pink or red |
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Microbe transmission |
Parts or products or pathogens direct contact, fomites, aerosol (airborne), oral (ingestion), and vectorborne. Some microorganisms can be transmitted by more than one route. |
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Portals of entry and exit |
Enteral, parenteral Leave same way they exit Respiratory tract Gastrointestinal tract Urogenital tract Skin or wound infections and blood |
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Adherence |
Attach to receptors on the cell surface and help colonisation eg. Finbriae on bacteria |
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Invasiveness |
Into tissues Eg. Produce digestive enzymes |
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Evasion |
Avoid detection/ attack by immune system eg. Within the cell eg. Antigenic variations in the influenza virus |
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Sterilisation |
Killing or removing all microbial growth Avenue of all living matter Physical- steam under pressure Chemical or radiation |
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Disinfection |
Reduction to a safe level Removal of all or most pathogenic microorganisms expect spores Not total destruction Most useless in presence of dirt or blood Chemical and heat |
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Physical defences |
Skin- rarely penetrates while intact, tightly packed cells which regularly shed Hair- protection against mechanical abrasion and prevents hazardous materials contacting skin Mucus membranes- tight junctions which secretary mucus Natural flora |
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Chemical defences |
Saliva mucus tears vagina and urine Flush surface and wash away microorganisms Contain chemicals like antibodies Gastric sections- stomach acid kills bacteria |
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Leukocytes |
Immune cells Defence against pathogens and attack abnormal cells Remove toxins and wastes Mister in lymphatic system or connective tissue |
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5 types |
Neutrophils: phagocytes Eosinophils- sensitive to allergies and attack parasites Basophils: release histamine and heparin Monocytes: enter tissues and become macrophages Lymphocytes |
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Phagocytosis |
Patrol the body looking for invaders Mostly neutrophils and macrophages formed from monocytes Attracted to the site by chemitaxis Adhere to target and clean and destroy foreign material Destroy by releasing toxic chemicals |
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Nk cells |
Lymphocytes which recognise and destroy abnormal cells without prior sensitisation |
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Inflammation |
Localised response which temporarily repaired the injury and prevents additional pathogens entering the wound Slows spread of pathogens from injury Destroys and removes agents Cleans up dead tissue and debris Promotes healing |
