Interactions between Humans and Microorganisms Flashcards
What are the different types of portal of entry ?
- mucous membranes
- skin
- placenta
- parenteral route
What are examples of a mucous membrane portal of entry ?
respiratory, GI tract, urogenital, eye
What are examples of a skin portal of entry ?
hair follicles, sweat glands, cuts, bites, stabs,
What does portal of entry mean ?
how microorganisms can enter your body
What is the placenta portal of entry ?
typically forms protective barrier to most pathogens
- syphilis, HIV, and toxoplasma can cross placenta
What is the parenteral route portal of entry ?
pathogens enter body by means other than gastrointestinal route (non oral)
- gets deposited directly into the tissue
- occurs in puncture by nails, thorns, needles, breaks in skin, surgery
Why is our normal flora important ?
acts as a protective barrier and keeps other microorganisms out
- can produce chemicals that prevent other microorganisms from growing
- prevents growth of other potentially harmful bacteria because it takes up space and doesn’t allow space for harmful bacteria
Why can antibiotic therapy hurt healthy flora ?
antibiotics can sometimes knock down the flora which lets other microorganisms enter
- will kill invader and the normal flora which decreases hosts defense
What is innate immune response ?
defense directed against any organism that tries to invade the host
- response is the same no matter what the microorganism can be (will hurt healthy microorganisms)
- not adaptable
How do mucous secretions protect from pathogens ?
saliva, tears, and mucous secretions wash away potential pathogens
How can mucus protect us from pathogens ?
can trap pathogens
How does cilia protect from pathogens ?
propel mucous-trapped pathogens from the respiratory tract
- hair like projections from epithelial cell lining respiratory tract
How does physiological barriers protect from pathogens ?
makes the environment inhospitable to pathogens inside your body
Ex.) pH: stomach pH kills most ingested pathogens
How does temperature protect from pathogens ?
- body temp inhibits growth of some pathogens
- fever response inhibits growth of some pathogens
What is phagocytic barriers ?
- will recognize invader and will destroy them while not harming the body itself
What are the physiological factors in inflammation response ?
- vasodilation: increased blood flow to area
- increased permeability of the capillaries: influx of fluid and cells
- accumulation of fluid: proteins and antibodies contribute to tissue edema
- fibrin is deposited: main component of blood clotting, if injured there will be a influx of phagocytic cells to injured cell
What are the 5 cardinal signs of inflammation ?
- heat
- redness
- edema
- pain
- loss of function
What is adaptive immunity ?
causes specific reactions to certain pathogens
- adapts to the pathogen
- more complex then innate immunity
In adaptive immunity what identifies that there is a invader ?
the antigen
What are cytotoxic cells ?
specific and are looking for a marker(antigen)
- stimulated by the antigen and will destroy pathogen
How does age affect host resistance ?
- babies up to 3 months do not produce antibodies and rely on maternal antibody protection
- the older the person the more the immune system decreases
How does nutrition affect host resistance ?
there is a correlation between the functioning of immune system and nutritional habits
How does treatment affect host resistance ?
- radiation and chemotherapeutic agents kill healthy cells which include immune cells
- antibiotics kill normal, healthy flora which increases chances of secondary infection
How can disease/chronic conditions affect host resistance ?
disease can cause normal function of the body to be increased or decreased
How does trauma affect host resistance ?
emotional or physical trauma weakens immune system
How does direct intrusion of physical barrier affect host resistance ?
if foreign object enters the body then that protective barrier is compromised which can let infections enter into the body
What is normal flora ?
microbes that colonize the body (internal and external) without normally causing disease
What are the benefits of normal flora ?
- prevents growth of other potentially harmful bacteria
- prevents attachment to tissue
- competes for nutrients with harmful bacteria
- consume lots of O2 leaving very little for other harmful bacteria
- produces acids, toxins, and peroxides that are toxic to harmful bacteria
What is an infection ?
bacteria that colonize body tissue and cause host to react with an immune response
What is a disease ?
noticeable impairment of body function
What is a infectious disease ?
when disease is caused by infectious bacteria or virus
Do all infections result in disease ?
no
What is colonization ?
establishment of bacterial growth on or within the host
What is a pathogen ?
any disease causing microorganisms or virus
What does pathogenic mean ?
disease causing
What does pathogenicity mean ?
ability to cause disease
What does opportunistic pathogen mean ?
cause disease in host with impaired immune system
- even normal flora can become an opportunist
What does virulence mean ?
characteristics of the bacteria or virus that makes it cause disease/pathogenic
What is more likely to cause disease, virulent or avirulent ?
virulent organism
- Strep pneumonia: species with capsules are virulent and more likely to cause pneumonia
What is less likely to cause disease, virulent or avirulent ?
avirulent organism
- normal throat flora: species without capsules are avirulent and not likely to cause pneumonia
What are the 3 classifications of pathogens ?
- extracellular pathogens
- facultative intracellular pathogens
- obligate intracellular pathogens
What are obligate intracellular pathogens ?
can only survive and reproduce inside host cells
- must grow in cell cultures
- chlamydia, viruses
What are facultative intracellular pathogens ?
will reproduce inside host cells and can live outside host cells
- can grow on artificial media that is enriched with special nutrients and growth factors
- can become intracellular under circumstances
- legionella, some salmonella, gonorrhoeae
What are extracellular pathogens ?
do not need to invade host cells to reproduce
- reproduce in spaces and fluids surrounding cells and tissues
- systemic infections
- largest # of pathogens and grow on artificial media
- staphylococci and streptococci
What is exotoxins ?
proteins that act as powerful poisons systemically to humans
- secreted from Gram + (most common) and -
- secreted from cytoplasm into surrounding areas when organism dies (following lysis)
- staphylococcus aureus
What are endotoxins ?
part of cell wall of gram - bacteria
- released from the cell wall
- released only when bacteria die and the cell wall breaks apart
- all of these infections have same effect on host
- salmonella
What does lysis mean ?
destruction of the cell
What are symptoms ?
subjective data that can’t be seen
- what the pt’s tell doctors
- pain, headache, chills, discomfort
What are signs ?
objective data that can be measured or observed
- swelling, rash, vomiting, diarrhea, fever
What are syndromes ?
manifested group of symptoms and signs that collectively characterize a particular disease or abnormal condition
- strep throat
What is the scientific method ?
process used to systematically investigate observations, solve problems and test hypotheses
What is the importance of the scientific method ?
helps scientists ensure that the theories they test are true by testing a hypotheses with tests
What is cellulits ?
diffuse purulent (pus) inflammation
- spreads between layers of the involved tissue
- may result from acute or chronic infection
- commonly by staphylococcus or streptococcus
What is granulomatous infection ?
chronic inflammation in which granulomas are formed
- body walls off the organisms (ex.) TB
- nodules caused by inflammation
- typically no symptoms but can be detected with chest x-ray
