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Definition
Cells that lack a membrane-bound nucleus are called prokaryotes (from the Greek meaning before nuclei). These cells have few internal structures that are distinguishable under a microscope. Cells in the monera kingdom such as bacteria and cyanobacteria (also known as blue-green algae) are prokaryotes.
Bacteria perform many important functions on earth. They serve as decomposers, agents of fermentation, and play an important role in our own digestive system. Also, bacteria are involved in many nutrient cycles such as the nitrogen cycle, which restores nitrate into the soil for plants. Unlike eukaryotic cells that depend on oxygen for their metabolism, prokaryotic cells enjoy a diverse array of metabolic functions. For example, some bacteria use sulfur instead of oxygen in their metabolism.
(Daniel Kunkel) |
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The most noticeable feature that differentiates these more complex cells from prokaryotes is the presence of a nucleus, a double membrane-bound control center separating the genetic material, DNA (deoxyribonucleic acid), from the rest of the cell.
In addition to the plasma membrane, eukaryotic cells contain internal membrane-bound structures called organelles. Organelles, such as mitochondria and chloroplasts, are both believed to have evolved from prokaryotes that began living symbiotically within eukaryotic cells. These vital organelles are involved in metabolism and energy conversion within the cell. Other cellular organelles within eukaryotic cell structure carry out the many additional functions required for the cell to survive, thrive, grow and reproduce.
Eukaryotic cells can reproduce in one of several ways, including meiosis (sexual reproduction) and mitosis (cell division producing identical daughter cells).
Read more at Suite101: Prokaryotic and Eukaryotic Cells: The Difference between Prokaryotes and Eukaryotes http://www.suite101.com/content/prokaryotic-and-eukaryotic-cells-a32332#ixzz19JzDw0Fl |
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Definition
| disease causing microbes often referred to as "germs" |
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| resulted from studying fermentation and spoilage of foods. The transmission of pathogens and infection through hands, surfaces, water and the air was documented, and the practices of asepsis were begun |
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| growth of microorganisms on a specific nutritious medium in a laboratory |
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Definition
unicellular organisms that do not require living tissue to survive. They vary in size and shape and are classified and named accordingly.
Unicellular
Cell wall—gram – or gram +
Classified by size & shape
Bacilli—rod shaped
Spirals
Cocci—spherical
Streptococci
Staphylococci |
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Definition
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| rod shaped organisms. EX: Clostridium tetani, the microbe causing tetanus or "lockjaw". The microbe survives as a spore in the soil and contaminates puncture wounds. A toxin from the bacterium causes seizures and muscle spasms and, eventually , respiratory failure. |
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| bacteria which include spirochetes and vibrios. EX: Treponema pallidum, the cause of syphilis and Borrelia burgdorferi, the agent causing lyme disease. |
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Definition
spherical formed bacteria. Further categorized by their characteristic groupings:
diplococci are pairs of spherical bacteria - pneumococcus
streptococci-chains frequently causing respiratory infections
staphylococci are clusters -staphylococcus aureus, a cause of skin infections. |
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Term
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Definition
outer rigid cell wall protects the microbe and provides a specific shape
cell walls are either gram neg or gram pos.-gram stain determines which
human cells do not have cell walls. So medications that act on the particular cell wall won't damage human cells.
cell membrane-inside cell wall. This semi permeable membrane selectively controls movement of nutrients and other materials in an out of the cell. Metabolic processes also take place in the cell membrane
external capsule or slime layer is found on some.
this layer is outside the cell wall and offers additional protection to the organism-it also interferes with phagocytosis and WBCs in the human body
flagellae attached to the cell wall for mobility
Pili or Fimbriae hairlike structures found on some bacteria
cytoplasm containing chromosomal DNA and RNA
Some secrete toxins |
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Term
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Definition
exotoxins -usually by gram positive bacteria and diffuse through body fluids. Produce an antitoxin or antibody reaction by the immune system
neurotoxin and enterotoxins included in this class.
endotoxins-present in the cell wall of gram negative organisms and are released after the bacterium die. may cause fever and general weakness or may have serious effects on the circulatory system causing endotoxic shock.
Enzymes-produced by some bacteria and are a source of damage to the host tissues or cells. Other enzymes assist the bacteria to invade tissue by breaking down components.
spores- a latent form of the bacterium with a coating that is highly resistant to heat and other adverse conditions. (tetanus and botulism) |
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Definition
process of bacteria replication
a division of the cell produces two daughter cells identical to the parent bacterium. |
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| differences between bacteria and human cells |
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Definition
bacteria have a cell wall and human cells do not
bacteria have flagella for movement
bacterial cells contain a ring of DNA and not a defined nucleus containing chromosomes
bacteria do not contain membrane bound organelles
bacteria are much smaller than human cells |
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Term
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Definition
very small obligate intracellular parasite that requires a living host cell for replication.
They can hide inside human cells and they lack their own metabolic processes or structures that might be attacked by drugs.
Very small obligate parasite that requires a host for replication
Viral DNA (most) or RNA
Protein coat or capsid |
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Definition
| extracellular virus particle. Consists of a protein coat or capsid and a core of either DNA or RNA. The protein coat comes in many shapes and sizes and undergoes change relatively quickly in the evolution of the virions. |
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Term
| chlamydiae, rickettsiae and mycoplasmas |
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Definition
| microorganisms that have some similarities with both bacteria and viruses. The replicate by binary fission (bacteria) but they lack some basic component; therefore they require the presence of living cells for reproduction. |
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Definition
grow everywhere
eukaryotic
growth promoted by warmth and moisture
reproduce by budding spores and extend hyphae
cell wall
only a few are pathogenic |
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Definition
eukaryotic
unicellular
motile
lack cell wall
occur in a number of shapes
pathogens are usually parasites
EX: malaria-mosquito
includes amebas |
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Definition
worms-not microorganisms
parasites and cause infections in humans
mulitcellular
eukaryotic
three stage lifecycle-egg, larva and adult
found in the intestine but can inhabit the lung or blood vessels during parts of their life cycle |
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Definition
protein-like agents that are transmitted by consumption of contaminated tissues or the use of donor tissues contaminated with the protein.
It induces proteins within the brain of the recipient to undergo abnormal folding and change of shape-fatal. |
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| areas of the body that lack flora |
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Definition
should be sterile and free of flora(microorganisms)
lungs
bladder
stomach
blood
cerebrospinal fluid
uterus, fallopian tubes, ovary
kidney |
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Definition
| occurs when a microbe or parasite is able to reproduce in or on the body's tissues. |
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Definition
consistently occurring in a particular population.
always present in a particular region |
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| a disease occurring in higher numbers than usual in certain population within a given time period |
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Definition
| source of infection -can be infected person, food source or animal. |
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| modes of transport from reservoir to new host |
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Definition
direct
indirect-contaminated food or hand, inanimate objects
droplet-oral or respiratory
aerosol-small particles from the respiratory tract remain suspended in the air
vector-borne-insect or animal |
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Definition
an infection acquired while in the hospital
UTIs most common |
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Definition
| proteins produced by human host cells in response to viral invasion of the cell. They influence the activity of nearby host cells, increasing their resistance to viral invasion and interfering with viral replication. |
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| factors affecting resistance |
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Definition
age
genetic susceptibility
immunodeficiency of any type
malnutrition
chronic disease
stress
inflammation or trauma affecting barriers
impaired inflammatory response (ex, long term glucocorticoid use) |
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Definition
| refers to the capacity of microbes to cause disease |
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Definition
degree of pathogenicity of a specific microbe based on:
invasive qualities
toxic qualities
adherence to tissue by pili, fimbriae or a specific membrane receptor sites
ability to avoid host defenses(mutation) |
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Definition
| percentage of deaths occurring in the number of persons who develop the disease |
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| where to find information on the latest diseases |
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Definition
| morbidity and mortality weekly report (CDC) |
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Definition
provide the basic guidelines by which all blood, body fluids and wastes are considered "infected" in any client regardless of the client's apparent condition.
two levels
general
specific to known infections at specific sites |
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Definition
removal of all microorganisms
exposure to heat using several methods including autoclaving
time packing and temperature are critical |
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Definition
| an appliance to sterilize instruments or materials with steam at high temperature and pressure |
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Definition
chemical solutions that are known to destroy microorganisms or their toxins on inanimate objects.
Few destroy spores-read directions
glutaraldehyde -most effective |
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Definition
chemicals applied to the skin that do not usually cause tissue damage, such as isopropyl alcohol -70%-active ingredient in hand sanitizers
reduce number but do not destroy all microorganisms |
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Definition
refers to the time between entry of the organism into the body and appearance of clinical signs of the disease.
Vary considerably
during this time the organisms reproduce until there are sufficient numbers to cause adverse effects on the body |
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Term
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Definition
| the time when the infected person may feel fatigued, lose appetite or have a headache and usually senses that "I am coming down with something" |
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Term
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Definition
| infectious disease develops fully and the clinical manifestations reach a peak. The onset of a specific infection may be insidious with a prolonged prodromal period or sudden or acute with the clinical signs appearing quickly with severe manifestations |
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| acute period is dependent upon? |
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Definition
| depends on the virulence of the particular pathogen and host resistance |
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Definition
| recovery period when signs subside and body processes return to normal. |
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Definition
| microbe reproduces within the body but does not cause signs or symptoms |
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Definition
| situation in which the pathogens are circulating and reproducing in the blood, affecting all systems and threatening life. An overwhelming systemic infection. |
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Definition
those of inflammation
heat
pain
swelling redness
lymphadenopathy
exudate, purulent |
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Definition
fever
leukocytosis
elevated ESR
fatigue, weakness, anorexia
headache, arthralgia |
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| sign of bacterial infection |
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Definition
purulent exudate or pus
leukocytosis (increased WBC count) |
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Definition
serous, clear exudates
leukopenia (reduction in WBCs count) |
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Definition
| swollen and tender lymph nodes |
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Definition
increase in monocytes
seen in chronic infections |
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Definition
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| indicator of inflammation in the blood |
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Definition
| c-reactive protein and erythrocyte sedimentation rate elevated (ECR) |
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| guidelines for effective drug therapy |
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Definition
1. drug should be taken at regular intervals over 24 hours to maintain blood levels
2. antimicrobial drugs should be taken until the medication is used up
3. respect to taking with or without food
4. best to identify specific organism and choose most effective antibiotic with least effect on good flora
5. drug allergies taken into consideration
6. antivirals just inhibit production but do not kill virus
antibacterial agents do not work on viruses |
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Term
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Definition
acts in one of four ways
1. interference with bacterial cell wall synthesis. Safe because human cells lack cell walls ex: penicillin
2. increase the permeability of the bacterial cell membrane, allowing leakage of bacterial cell contents
3. interfere with protein synthesis and cell reproduction. These have effects on fetus and young child.
4. interfere with the synthesis of essential metabolites. |
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| problem with antibacterial drugs |
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Definition
allergic reaction
mild and severe and digestive problems
secondary infections may occur due to a wiping out of good flora or an imbalance of flora |
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Definition
decrease the reproduction of viruses inside the host cell but cannot destroy the virus.
control but do not cure.
some are only effective against actively replicating viruses
tend to have adverse effects on the host because they alter viral interaction within the host cell |
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Definition
| interfere with mitosis in fungi or may increase fungal membrane permeability.Most are topical (athletes foot) |
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Definition
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Definition
Most of them replicate in the cytoplasm. They don’t require as much polymerases of their host to replicate as DNA viruses do. Examples of human diseases caused by RNA viruses are SARS, influenza, hepatitis C, etc.
RNA viruses genetic information is stored, as their name suggests, in RNA, not DNA. This has important consequences in the life cycle of the virus - and gives it the potential to outwit the immune system.
makes frequent mistakes during copying - averaging one mistake per 10,000 nucleotides each time it is copied, and has less of an ability to correct errors. Since in normal cells RNA molecules are not "blueprint" quality, the host cell does not check copied RNA as carefully as it does DNA to assure that it is free of errors. These properties make RNA very poorly suited for the storage of information - which explains why all other organisms use it only as a temporary messenger molecule.
However, these very properties make RNA ideal for the storage of viral information. Once the immune system has learned to recognize an infecting virus and create antibodies against it (developed an immunity), it can quickly destroy it, so the virus can no longer use that host for reproduction. In order to reinfect that host - it must first change its nature enough that the immune system will no longer recognize it. In other words, it must mutate.
The unstable nature of the RNA molecule provides this mutagenic factor, allowing RNA viruses to evolve far more rapidly than DNA viruses, frequently changing their surface structures. These mutations make it more difficult for an organism to develop any kind of lasting immunity to the virus. |
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| disease causing pathogens |
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Definition
Bacteria
Viruses
Chlamydiae, rickettsiae, & mycoplasma
Fungi
Protozoa
Helminths
Prions |
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Term
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Definition
Exist in two forms:
Elementary body-infectious form
Reticulate body-noninfectious form that uses the host to replicate to become elementary bodies
Chlaymydial infection is a STD that causes PID. PID may affect the infant born to the mother. |
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Definition
Gram negative bacteria that reside w/in the host & are transmitted through an insect vector such as lice or ticks.
Ex—rocky mountain spotted fever |
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Definition
| Smallest cellular microbe that is a common cause of pneumonia. |
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Definition
Found everywhere. Like to live on dead organic material. “Don’t pick that up, you don’t know where it has been!”
Few fungi are pathogenic
Tinea pedis (athlete's foot)
Candida—harmless fungi that may cause problems in immunosuppressed patients |
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Definition
Eukaryotic unicellular & motile
Pathogens are usually parasites
Trichomonas
Plasmodium
Entamoeba histolytica |
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Definition
Worms!
Abnormal molecule that is transmitted through the blood of animals or humans |
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Term
| transmission of pathogens |
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Definition
Direct contact: person to person
Indirect contact: intermediary object
Droplet to oral or respiratory system
Vector-borne: insect or animal intermediary |
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Definition
Healthy individuals usually are resistant to infection
Interferons: produced by cells in response to viruses that make nearby cells more resistant
Factors that decrease resistance
Age
Genetic disposition
Immunodeficiency
Malnutrition
Chronic disease
Stress
Inflammation or trauma affecting skin or mucosa
Poor inflammatory response
May need prophylactic medications |
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Definition
Universal precautions
Hand washing
Cover mouth when coughing or sneezing
Good hygiene
Avoid sick people
Safe water and food supplies
Block portal of entry
Sterilization: heat & autoclave
Disinfectants: chemicals that destroy pathogens
Antiseptics: disinfectants that go directly on skin |
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Term
| onset and course of infections |
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Definition
Incubation period: time between entry into body and clinical signs of disease
Prodromal period: early infection period when signs are nonspecific
Insidious: long prodromal period
Acute period: infection develops fully
Recovery or convalescent period
Chronic infection
Septicemia: becomes systemic through bloodstream |
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Term
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Definition
Local signs
Inflammation
Pain
Tenderness
Redness
Pus or serous exudates
Systemic signs
Fever
Fatigue
Weakness
Cognitive involvement |
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