Chapter 22- Introduction to microbiology and human disease Flashcards
Define bacteria
simple, single-celled organism.
found in freshwater, saltwater, soil, and other living organism.
Define viruses
they are not cells; smaller and simpler in structure compared to bacteria and paracites- since they only reproduce only within the living cells of a host.
Define Protoza
single-celled animals, such as amoebas.
free living in freshwater or saltwater, they consume bacteria, fungi and each-other.
define Fungi
unicellular or multicellular. they decompose organic matter in the soil and freshwater and help recycle nutrients.
Define worms
multicellular animals
free living within the soil they consume dead organic matter or smaller living things.
define arthropods
(joint lefts) multicellular animals such as lobsters, and shrimp. Some insects are vectors of disease- they spread pathogens from host to host when they bit.
Define the process of binomial nomenclature
scientific names have 2 parts: binomial nomenclature.
name = genus and species.
genus= larger category and Capitalized
Species= second category and not capitalized.
what is normal Flora-microbiota?
natural population of microorganisms living in us.
categorized into resident flora (species that live on or in nearly everyone at all times ) or transient flora (species found periodically on or in the body.
What is a resident flora that turned to an opportunist?
bacteria that live in one area of the body and are harmless, but they can end up in other parts of the body and be harmful.
Term means “ harmless species that has become a pathogen in special circumstances”
How does a microorganism cause an infection?
enter and establish itself in a host and begin reproducing.
What is the term given for the ability of a pathogen to cause a disease
virulence
what is host resistance?
the total of the body’s defences against pathogens.
what are examples of human body defences?
intact skin
mucous membranes
sweeping of cilia in respiratory tract
describe the distribution of normal Flora-Microbiota in the human body specifically the skin.
exposed to the environment, large bacterial population and small number of fungi.
describe the distribution of normal Flora-Microbiota in the human body specifically the nasal cavities.
bacterial, mold spores, and viruses enter.
chiliated epithilium limits microbial population by sweeping mucus and trapping pathogens in the pharynx to be swallowed.
describe the distribution of normal Flora-Microbiota in the human body specifically the trachea, bronchi, and lungs
cilia of the trachea and large bronchial tubes sweep mucus and microbes upwards towards to pharynx where they are swallowed.
those that base are destroyed by alveolar macrophages
describe the distribution of normal Flora-Microbiota in the human body specifically the oral cavity
large bacterial and small number of yeast and protozoa. kept in check by lysosyme, (saliva), resident flora help prevent growth of pathogens
describe the distribution of normal Flora-Microbiota in the human body specifically the esophagus
contains microorganism swallowed with saliva or food
describe the distribution of normal Flora-Microbiota in the human body specifically the stomach
hydrochloric acid kills most bacteria,
describe the distribution of normal Flora-Microbiota in the human body specifically the small intestine
ileum has the largest bacteria population, the duodenum has the smallest
describe the distribution of normal Flora-Microbiota in the human body specifically the large intestine
contain enormous population of bacteria, which inhibits the growth of pathogens and produces vitamins.
describe the distribution of normal Flora-Microbiota in the human body specifically the urinary bladder
virtually free of bacteria, lower urethra has flora similar to that of the skin
describe the distribution of normal Flora-Microbiota in the human body specifically the vagina
large bacterial population that creates an acidic pH that inhibits the growth of pathogens.
Imbalance of bacterial usually results in Yeast infections
describe the distribution of normal Flora-Microbiota in the human body specifically the tissue fluid
small number of bacteria and viruses penetrate mucous membranes or get thorugh breaks of skin. Most destroyed by lymph nodules of lymph nodes or by wandering macrophages in tissue fluid.
describe the distribution of normal Flora-Microbiota in the human body specifically the blood
should be free of microorganism
what are clinical and subclinical symptoms?
clinical= apparent or symptomatic subclinical = innaparent or asxs
what do you call the time prior to symtpoms appearing once a pathogen has established itself in a host.
incubation period.
some dieases are specific periods, and others are variable.
what is the prodromal period?
short time period that may follow the incubation period
> here vague, non-specific sxs may begin and are very generalized.
some diseases are self-limiting. what does this mean?
they last a cetain length of time and are usually followed by recovery.
ie: cold, chickenpox, mumps
Terminology of infection may refer to the location of the pathogens in the body, to the general nature of the disease or to how the pathogen was acquired.
Define localized infection
infection is confined to one area of the body
Terminology of infection may refer to the location of the pathogens in the body, to the general nature of the disease or to how the pathogen was acquired.
Define systemic infection
pathogen is spread throughout the body by way of the lymph or blood.
Terminology of infection may refer to the location of the pathogens in the body, to the general nature of the disease or to how the pathogen was acquired.
Define Bacteremia and septicemia infections
Bacteremia: bacteria that are present are multiplying rapidly
septicemia: serious because here the immune defences have been overwhelmed and are unable to stop spread of pathogen
Terminology of infection may refer to the location of the pathogens in the body, to the general nature of the disease or to how the pathogen was acquired.
Define Secondary infection
when a primary infection that has lowered the host’s resitence, and a second infection occurs.
Terminology of infection may refer to the location of the pathogens in the body, to the general nature of the disease or to how the pathogen was acquired.
Define Nosocomial infection
acquired in hospitals or institutions such as nursing homes. Where peoples resistance to diseases are lowered.
Terminology of infection may refer to the location of the pathogens in the body, to the general nature of the disease or to how the pathogen was acquired.
Define endogenous infections
infection where nosocomial infection caused by patients own normal flora that has been inadvertently introduced into an abnormal body side.
With respect to timing and duration infections can be called acute or chronic. Differentiate the two.
acute= begins abruptly and is severe chronic= slow progress, and may last for a long time.
Define epidemiology
study of the patterns and spreading of a disease in a population
define epidemic
outbreak of disease/number of cases in a given time period
define endemic disease
disease that is present in a population with an expected or usual number of cases in a given time
ie: influenza in large cities during winter
define pandemic
is an epidemic that has spread throughout several countries.
ie: meningitis, AIDS.
what is meant by portal of entry
the way the pathogen enters a host.
oe: breast of skin, inhaled, consumed, aquired.
what is meant by portal of exit?
the way the pathogen leaves the body or is shed from the host.
what do you call a person who harbours a pathogen and acts as a reservoir of it to others?
a carrier
what is a zoonoses disease?
animal diseases that humans acquire in certain circumstances.
Infections are spread in one of two ways: noncommunicable and communicable. Differentiate these terms
noncommunicable: resident species causes disease under certain conditions or in which a non-resident species causes disease when it enters the body. Cannot be transmitted directly or indirectly from host to host.
communicable: pathogen may be transmitted directly or indirectly from host to host.
Give examples of direct and indirect spreading of communicable diseases.
direct via saliva, blood, sexual contact
indirect: water, food, vector or fomites (inanimate objects)
Define contagious
diseases are easily spread from person to person by casual cuteness contract or respiratory droplets.
What are methods of control of microbes used in the environment?
- use of chemicals for disinfection
2. protection of food and water supplies.
define antiseptic
chemical that destroys bacterial or inhibits their growth on a living being.
define disinfectant
chemical that is used on an inanimate objects.
Chemicals with antibacterial effect may be classified into bactericidal or bacteriostatic. Differentiate these two terms
bactericides= kill bacteria by disrupting important metabolic process bacteriostatic= do not destroy bacteria but inhibit their reproduction and slow their growth.
define sterilization
process that destroys all living organism.
Usually by an autoclave- which is a chamber in which steam is generated under pressure.
How is milk regulated for bacteria?
its pasteurized, which is a heating method of sterilization.
How is city drinking water typically regulated for bacteria?
usually chlorinated.
Bacteria is classified into one of 3 shaping categories. name them
1, coccus: sphere
- bacillus; rod shape
- spirillum: long cell with one of more curves or coil
define the characteristics of the bacterial classification system below:
s. Staphylo
2. Stepto
3. Diplo
- cluster
- chain
- pairs
What are flagella?
long threadlike structures that project from the cell and beat rhythmically
bacteria reproduce by process of binary fission. what is this?
chromosomes duplicates itself, and original cell divides into two cells.
What are aerobic bacteria?
What are anaerobic bacteria ?
What are Facultatively anaerobic bacteria?
- Aerobic: can reproduce only in the presence of oxygen
- reproduce only in the absence of oxygen
- bacteria not inhibited in either situation; they can reproduce in either present or absence of oxygen
On the basis of chemical in their cell walls, most bacteria can be put into one of two groups. Gram positive and gram negative. what is this?
gram staining is lab test which shows the shape of the bacteria and their reactions to staining methods (seen using a telescope and tissue samplig).
+ve gram stain appear purple or blue
-ve gram stain appear pink or red.
Bacteria can be categorized based on their special characteristics what does this mean?
some can have:
> capsules: deletions sheath that encloses the entire cell. Antigenic capsule mean they stimulate antibody production by our lymphocytes.,
> form spores: dormant inactive stage that consists of the chromosomes and small amount of cytoplasm and cell wall.
> produce toxins: chemicals that are harmful to the host tissues.
what are neurotoxins and endotoxins?
neuro= toxins that affect nerve cells endotoxins= cause fever and circulatory shock.
what is endotoxin shock?
AKA gram-ve shock.
Life-threating condition that accompany serious infections with gram -ve bacteria.
What to Rickettsias and Chlamydias differer from most bacteria?
they are obligate intracellular paracites.
antibiotics are chemicals that are used to treat bacterial infections. what are broad-spectum and narrow-spectrum abx?
- that affects many kinds of bacteria
2. affects only a few kinds of bacteria
what is bacterial resistance?
a consequence of abx use, it means that the bacteria are able to produce an enzyme that destroys the antibiotic, rendering it useless.
describe a virus
not a cell, but rather DNA or RNA surrounded by a protein shell called capsid. They are never both DNA and RNA.
Rhey replicate within the cells of a host
most fungi are saprophytes. Define this.
they live on dead organic matter and decompose it to recycle the chemicals or nutrients
what do you call the pathogenic fungi that cause infection?
mycoses.
They can be superficial or systemic
arthropods are ectoparasites. What does this mean
they live on the surface of the body.
