Chapter 3 Flashcards
How are newborns colonized
born with coating of microbes, and when they are breastfed they also receive microbes (this coating is absent in c sections, but babies catch up within 6 months)
microbe free areas (part 1)
Body fluids:
- Blood
- Cerebrospinal fluid
- Saliva prior to secretion
- Urine in kidneys and in bladder
microbe free areas (part 2)
Internal tissues and organs:
- Middle and inner ear
- Sinuses
- Internal eye
- Bone marrow
- Muscles
- Glands
- Organs
- Circulatory system
- Brain
- Spinal cord
- Ovaries and testes
areas colonized by microbes
- Nose
- Mouth
- Skin
- Intestines
- Scalp
two types microflora
resident and transient
resident microflora
Microbes that are always present on or in the human body
transient microflora
Microbes that can present under certain conditions in any location where resident microflora are found
symbiosis
Association between two (or more) species living together – includes mutualisms, commensalisms, and parasitism
Mutualism
Both members of the association living together benefit from the relationship
ex: bees getting food from flowers and flowers being pollinated to reproduce
parasitism
One organism, the parasite, benefits from the relation, whereas the other organisms, the host, is harmed by it
ex: fleas
Commensalism
Two species live together in a relationship such that one benefits and the other one neither benefits nor is harm
ex: vultures following predators to feed on leftovers
What are the reason why organisms change the type of symbiotic relationship with host and become opportunistic?
Conditions for opportunistic organisms
- Failure of the host’s normal defenses
- Individuals with weakened immune defenses
- Malnutrition
- Presence of another disease
- Elderly or very young - Babies without fully developed immune systems may have microbes - that take advantage of this
- Treatment with radiation or immunosuppressive drugs
- Physical and mental stress
Microbes in unusual locations
Microflora disturbances
- Microbial antagonism - Losing good microbes
- Compete with pathogens
Pathogenicity
the capacity to produce disease in a host (its pathogenic or not), depends on the organism’s ability to: invade host, multiply in host, and avoid being damaged by the hosts defenses (RAT EXAMPLE)
Virulence
intensity of disease varies based on pathogen. Omicron strand of covid was less virulent than the delta strand, because it had weaker symptoms
Attenuation
when virulence is decreased, weakening the disease producing ability of the pathogen. This happens when the parasites kill the hosts by mistake
Microbial count
a threshold of microbes that we are supposed to have, when this number is exceeded, we get diseases. Shigella only needs 10 organisms to cause dysentery
Endotoxins
- Gram negative (the microbes that make the endotoxins are gram negative)
- Consist of LPS - lipopolysaccharide molecule
- Fever
- Shock
- Released at cell death (can kill patients when they are all released at once and cause shock)
Exotoxins
- Gram positive and some Gram negative
- Proteins, usually enzymes
– Examples: Hemolysins
– Alpha, Beta, Gamma
– To release iron - Neurotoxins
– Botulism versus Tetanus toxins - Potent effects
– Including on toxoids - Specialized tissue damage (botox is an exotoxin)
- Secreted
Contamination
unwanted organisms are present, beginning step, organisms are just there
Infection
multiplication of parasitic organisms within or on the host’s body
Disease
A disturbance in the state of health wherein the body cannot carry out all is normal functions, Disrupts the normal functioning of the host , Effects range from mild to severe
Symptom
Characteristic of the disease that can be observed or felt only by the patient (headache)
Sign
Characteristic of the disease that can be observed by examining the patient (temperature)
Syndrome
The combination of signs and symptoms that are indicative of a particular disease (IBS)
