Unit 2 Lesson 2: Infection: Know Your Enemy Flashcards
Microorganisms
living organisms too small to be seen with the naked eye—are around us all the time
Where do microorganims live
They live on the surface of our skin, in air and water, and on the things we may touch.
Where does flora live and what does it do there
in our intestinal tract help us to digest our food, make important nutrients for our bodies, and crowd out harmful organisms.
Where do microorganims live on our bodies? Are they harmful?
Inside our bodies, microorganisms live deep in our skin and in our organs, mostly not harming us at all.
Flora
flora—microorganisms that exist in and on animals and humans without causing disease—
How many microorganims are in our body
We have trillions of microorganisms living within us all the time, most of them helping with the processes of life.
Many of these nice little “germs” are our friends, but what makes us sick?
Pathogens
Pathogens
Pathogens are microorganisms capable of causing disease.
Microorganisms can come in different types, the most common being
bacteria, viruses, and fungi.
What can Protozoa and parasites be classfied as
Protozoa and parasites can also be pathogens
Can normal flora become pathogen? If so, how?
Normal flora can become pathogens if they enter a part of the body that they don’t normally inhabit, such as when the intestines become ruptured and allow digestive microorganisms to enter the abdominal cavity, causing infection.
Pathogens go through a process we describe as the chain of infection
a series of events that need to happen for infections to spread.
What is the first link of the chain of infection
The first link in the chain is the infectious agent itself, which can be any type of microorganism that can cause disease.
The infectious agent needs to inhabit a
reservoir
The infectious agent needs to inhabit a reservoir:
a place where pathogens survive and multiply.
Living reservoirs for disease include
human body, animals, and insects.
Nonliving reservoirs include
soil, water, food, and surfaces.
Microorganisms can be found on any surface in the environment and are especially prevalent in hospitals. Where do most pathogens thrive
Most pathogens thrive in warm, moist, dark environments, but many can survive other conditions.
Certain people can harbor pathogens in their bodies while their body’s defense keeps them from getting ill; these people are called
carriers, and they act as reservoirs for infectious agents.
What do pathogens multiply quickly food
Pathogens need nutrients to survive, and therefore can grow and multiply quickly in food.
How do we kill microorganisms in food
When we cook foods at high temperatures or add salt, we are killing microorganisms or preventing their growth.
Moist environments like wounds or the throat are reservoirs where pathogens can
Moist environments like wounds or the throat are reservoirs where pathogens can also multiply easily.
Pathogens that harm humans mostly prefer a temperature of approximately
95°F
Why does the body heat up (why do we get fevers)? What is your body trying to do when one gets a fever
Pathogens that harm humans mostly prefer a temperature of approximately 95°F. Coincidentally, that temperature is close to the normal temperature of the human body. Thus, when your body runs a fever, it is defending against pathogens by changing the temperature of your body to a level that is less conducive to the infection you are fighting off.
Many microorganisms also need oxygen to survive, and these are called
aerobic organisms
. Some are the opposite, either not requiring oxygen to grow or actually being killed by the presence of oxygen—these are
anaerobic organisms
Think of how much care you need to take with a puncture wound from a rusty nail:
the bacteria that causes tetanus can only survive when oxygen is not present, deep in that puncture wound.
What are other condiiton pathogens need
Other conditions that pathogens need are specific pH levels (acidic or alkaline) or light levels.
What are something bacteria are killed by
Some bacteria are killed by stomach acid, while others can be killed by using ultraviolet light.
Continuing on our chain of infection, the infectious agent needs to have a way to get out of the reservoir
a portal of exit
The most frequent portal of exit for human or animal reservoirs is through
bodily fluids
The most frequent portal of exit for human or animal reservoirs is through bodily fluids. What are some examples of this
Blood, urine, mucus, saliva, breast milk, feces, vomit, semen or other secretions can carry disease out of the body
What happens when you sneeze
When you sneeze, any pathogens in your respiratory system can exit the body through droplets.
What happens when you vomit or have diarrhea
For an intestinal pathogen, vomit or diarrhea can be the portal of exit.
What happens when you have cuts and abrasions
Cuts and abrasions can offer an opportunity for infections to spread through blood or pus.
Once the pathogen has exited the reservoir, it needs a ? to get to a susceptible host
mode of transmission
How does direct transmisson happen
Direct transmission happens when the microorganism moves from one person to the next through touching, kissing, sexual contact or even a droplet entering the nose or mouth from an infected person.
How does indirect transmission happen
ndirect transmission occurs when the pathogen moves to another object and is then picked up by a susceptible host. If you cough into your hand and then touch a doorknob, a person who touches that doorknob may pick up the pathogen that exited your body
How long can microorganisms survie on a surface?
Some microorganisms can survive for years on a surface, while others only survive for a few seconds outside of a reservoir.
Transmission types: droplet transmission
droplet transmission, where the pathogen travels in water droplets expelled when a person exhales, coughs, sneezes, or talks
Transmission types: airborne transmission
airborne transmission, whereby infectious organisms float through the air and can travel in heating and cooling systems
Transmission types: vector-borne transmission
A vector is an organism that carries the pathogen to the susceptible host, most often an insect like a mosquito, that bites or stings the host.
Pathogens always cause infections.
True or False
Flase: Yes, pathogens are around us all the time. They are capable of causing disease if the chain of infection occurs, but the conditions have to be right for that to happen.
The portal of entry to a susceptible host can be a normal opening of the body, like the
nostril, eye, mouth, anus, urethra, or it can be through abnormal openings like cuts, surgical incisions, or insertion sites of tubes or needles.
What is the portal of enetry for vectors
Vectors create their own portals of entry by biting through the skin.
What is a susceptible host
A susceptible host is a person who is at risk for infection because they can’t fully defend against the invading pathogen.
People are more susceptible to infection because of numerous possible factors including
ng age (young or old), compromised immune system, or immune deficiency.
