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105 Cards in this Set

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Define Normal Microbiota

colonize the surfaces of the body without normally causing disease

Resident Microbiota

stay through the person's entire life

transient microbiota

stay in the body temporarily.

Could be dislodged by competition, the body's defenses, or chemical and physical changes

most resident microbiota are: (type)


What do commensal resident microbiota do?

feed on excreted cellular wastes and dead cells

how do we acquire normal microbiota?

through the birthing process and in the first stages of life (the womb is anexic)

Opportunistic Pathogens

normal microbiota or other normally harmless microbes that can cause disease under certain circumstances

What provides opportunities for opportunistic pathogens?

1. introduction of normal microbiota to an unusual site in the body

2. immune suppression

3. Changes in normal microbiota

microbial antagonism

when normal microbiota take up space and use up the nutrients, it makes it less likely that another species could invade

reserviors of infection

sites where pathogens are maintained as a source of infection


diseases that spread naturally from their usual animal hosts to humans

how can a human acquire zoonoses?

direct contact wi/ animals or their waste/ eating the animal/ blood-sucking anthropods

two types of human reserviors

humans with active diseases


examples of nonliving reserviors

soil, water, and food

why are human infections with zoonoses difficult to irradicate?

sheer number and types of reserviors

do humans serve as reserviors for animals?

not typically

what are human reserviors: carriers?

people with no obvious symptoms before or after an obvious disease. May be infected with no symptoms for years

how do nonliving reservoirs become reservoirs?

usually because they become infected by feces or urine

three basic modes of transmission

contact transmission

vehicle transmission

vector transmission


from a reservoir or a portal of exit to another host's portal of entry

direct contact transmission

typically involves body contact between hosts

examples of direct contact transmission


touching, kissing, sex, biting, scratching



indirect contact transmittion

pathogens spread from one host to another by fomites


inanimate objects that are inadvertently used to transfer pathogens to new hosts

Define droplet transmission. What type of transmission is it under?

droplets are expelled when we exhale, sneeze, cough, etc. Considered contact transmission if it travels less than 1m

vehicle transmission

the spread of pathogens via air, drinking water, and food, as well as bodily fluids being handled outside the body

airborne vehicle transmission

pathogens that travels more than 1m to respiratory mucous of new host

what is significant about waterborne vehicle transmission?

important in the spread of GI illnesses

types of vehicle transmission




bodily fluid transmission


arthropods that transmit diseases from one host to another

biological vectors

-transmit pathogens

-serve as a host for pathogens to replicate

-pathogens can replicate within a biological vector, then enter new host from a bite.

mechanical vectors

not required as a host, only passively carry pathogens to no hosts on their feet or other body parts

ie- houseflies and cockroaches

what is the most common and most frequently used portal of entry?

respiratory tract


presence of microbes in or on the body


a successful invasion of the body by a pathogen (may or may not result in disease)

what are the three major portals of entry


mucous membranes


parenteral port of entry

not a portal of entry but a means by which the portals can be circumvented. pathogens are directly deposited


the process by which microorganisms attach themselves to cells and organisms must adhere to host cells if they want to infect them

concerning adhesion, what can inhibit an infection?

blocking or changing the ligand or receptor


~when parasitic injury is significant enough to interfere with the normal functioning of the body

~any change from a state of health


subjective characteristics of a disease than can be felt by a patient


objective manifestations of the disease that can be observed or measured by others


group of symptoms and signs that collectively characterize a particular disease or abnormal condition

asymptomatic infections

go unnoticed because they have no symptoms

stages of infectious diseases

-incubation period

-prodromal period





the ability of a microorganism to cause disease


the degree of pathogenicity

does pathogenicity or virulence tell us how sever the disease is?


virulence factors allow the pathogen to:

-interact with and enter host

-adhere to host cells

-gain access to nutrients

-escape detection or removal by the immune system

types of virulent factors:

adhesion factors

biofilm formation

extracellular enzymes


antiphagocytic factors

how to extracellular enzymes help pathogens?

enables them to dissolve structural chemicals in the body and maintain an infection, invade further, and avoid body defenses

examples of extracellular enzymes

Hyaluronidase and collagenase




chemicals that either harm tissues or trigger host immune responses that cause damage

difference between toxins and extracellular enzymes?

no clear - many enzymes are toxic and many toxins have enzymatic action


toxins enter the bloodstream and are carried to other parts of the body

two types of toxins

exotoxins and endotoxins


proteins produced by gram-positive and -negative bacteria that detroy host cells or interfere with host metabolism

- cytotoxins, neurotoxins, and enterotoxins


-only gram-neg

-Lipid A

released when cells die and can stimulate the body to release chemicals that cause a bunch of issues and can potentially be life-threatening

the longer a pathogen remains in a host...

...the greater the damage and the more severe the disease

What do WBCs do to limit the extent and duration of infecitons?

engulfs and removes pathogens via phagocytosis

what do capsules do?

make the organisms slippery. can be made of things found in the body

antiphagocytic chemicals

some prevent fusion of lysosome and phagosome, some inhibit phagocytosis, soem directly destroy phagocytic WBCs


the number of new cases of a disease in a given area or population during a given period of time


the total number of cases, both new and already existing, in a given area or population during a given period of time


a disease that normally occurs continually at a relatively stable incidence within a given population or geographical area


only a few scattered cases occur within an area


when a disease occurs at a greater number than usual


when an epidemic occurs simultaneously on more than one continent

Healthcare associated infection

infections acquired by patients or healthcare workers while they are in health care facilities

types of HAIs




Exogenous HAI

pathogen acquired from a healthcare environment

endogenous HAI

arise from opportunistic normal microbiota within the patient due to factors within the health care setting

iatrogenic HAI

results from modern medical prodecures


result from the use of antimicrobial drugs that inhibit some resident microbiota and allow others to survive

factors that result in HAIs

-presence of microorganisms in hospital environment

-immunouncompromised patients

-transmission of pathogens between staff and patients and among patiens

species resistance

resistance due to the cells and physiological processes of humans that are incompatible with those of most plant and animal pathogens

how do humans show species resistence?

dont have the correct temp or ph for the path to survive // dont have the correct receptors

first line of defense

external physical barriers to pathogens

second line of defense

internal and composed of protective cells, bloodborne chemicals, and the processes that inactivate or kill invaders

third line of defense

responds against unique species or strains of pathogens


broad-spectrum antimicrobials found in eccrine sweat glands

what in skin hurts pathogens?

salt, dermicidins (antimicrobial) , lysozyme (destroys cell wall)

what does sebum do?

helps keep skin pliable and less likely to break or tear AND lowers the ph of skin to a level inhibitory to many bacteria

lacrimal apparatus

group of structures that produce and drain away tears that join the nasal mucus and flow into the pharynx

what do tears contain to hurt pathogens?

lysozyme and defensins

what does mucous contain to hurt pathogens

lysozyme and defensins

how does normal microbiota help with dealing with pathogens?

competes with new pathogens by consuming all the space and nutrients // change ph to make it uninhabitable // stimulate body's second line of defense // provide vitamins

antimicrobial peptides

(defensins) you can find them on skin, mucous membranes, and neutrophiles and they are triggered by sugar and protein molecules on the external surfaces of microbes

where are the majority of the second line defenses created/located?


there is overlap between the first and second lines of defense



includes iron-binding proteins transferrin and ferritin which transport and store iron for humans, but they sequester iron from microbes

three types of formed elements

erythrocytes, platelets, and leukocytes


carry oxygen and carbon dioxide in the blood


involved in blood clotting



involved in defending the body againts invaders


have large granules in their cytoplasm that stian different colors depending on the type

basophils, eosinophils, neutrophils


not phagocytic

can migrate from bloodstream to tissue

release inflammatory chemicals which influence the tone and diameter of blood vessels



can migrate from bloodstream to tissue

defend against parasitic worms

play role in allergic reactions



rapidly move from bloodstream to tissue


cytoplasm appears uniform under a light microscope

lymphocytes, monocytes


most involved in adaptive immunity


leave the blood and mature into the phagocytic cells called macrophages (phagocytic cells)


transporting a solid substance into a eukaryotic cell

6 stages of phagocytosis








the coating of a pathogen with proteins that help to increase phagocytosis

- increases the number and kinds of phagocyte binding sites on a microbe's surface