MIBO 3500 EXAM 4 STUDY GUIDE WITH
100% CORRECT ANSWERS
23.a Identify areas of the human body colonized by microbes and areas that remain sterile;
explain why there are different types of microbes in the microbiota of different areas of the
body.
Areas of the body that are colonized by microbes:
Skin
-Mostly gram-positive species such as Staphylococcus epidemidis, Bacillus species,
and Propionibacterium ances
Oral & nasal cavities
-Non-pathogenic Neisseria, Streptococcus, Actinomyces, Lactobacillus, Treponema denticola,
Porphyromonas gingivalis, Streptococcus mutans, Streptococcus salivaeris
Respiratory tract (lungs and trachea)
Urethra
-Staphylococcus epidermidis, Entercoccus sp.
Bladder
-Some anaerobes
Vagina
-Lactobacillus, Firmicutes, yeasts
Stomach
-Only few microbes like H. pylori can survive
Intestines
-Many species of bacteria in feces; most notably E. coli and Bacteroides thetaiotaomicron
23.a Identify areas of the human body colonized by microbes and areas that remain sterile;
explain why there are different types of microbes in the microbiota of different areas of the
body.
Areas of the body that remain sterile:
-Kidneys
,-Ureters
-Heart
-Blood
-Cerebrospinal fluid
23.a Identify areas of the human body colonized by microbes and areas that remain
sterile; explain why there are different types of microbes in the microbiota of different areas
of the body.
There are different types of microbes on different areas of the body due to the fact that each
area has vastly different environmental factors that affect a microbe's ability to persist. Some
bacteria are better equipped to survive in different areas than others. Such conditions include:
-Moisture levels
-pH
-Temperature
-Salinity
-Competition with other bacterial species
-Energy source availability
-Enzymes that prevent growth
23.b Explain the hygiene hypothesis.
Hygiene hypothesis- exposure to more microbes and other environmental antigens early in life
may produce a more tolerant, well-controlled immune system that is less prone to inflammatory
and autoimmune diseases.
-Today we have more restricted access to microbes that are helpful in training our immune
system due to indoor living and using of antimicrobials
23.c Explain the benefits of gut microbiota and contrast that to when the microbiota moves
beyond the gut or comes into imbalance (give specific examples for beneficial microbes and
diseases that result from dysbiosis
Benefits of the gut microbiota:
-Commensal microbes make vitamins (E. coli makes B12) and catabolize the foods we eat
(Bacteroides thetaiotaomicron breaks down complex carbohydrates)
-Commensal organisms also prevent colonization by pathogens---> they are competitors for
food and space that is needed for attachment and growth; can also secrete toxins that kill other
bacteria (E. coli produces bacteriocin)
, -These organisms promote development of a healthy immune system and regulate the immune
response in the gut (some can reduce inflammation such as Bacteroides
fragilis and Faecalibacterium prausnitzii)
-The gut-brain axis has bidirectional signaling between the gut and brain that can affect
behavior and mood
23.c Explain the benefits of gut microbiota and contrast that to when the microbiota moves
beyond the gut or comes into imbalance (give specific examples for beneficial microbes and
diseases that result from dysbiosis
Harms from moving beyond the gut:
-Bacteroides fragilis can invade tissues through surgical wounds and cause abcesses or
gangrene
-Other issues such as UTIs, septicemia, and meningitis can occur
Dysbiosis (imbalance in microbial composition):
-Can occur through changes in diet, emotional stress, or antibiotic therapy
-Antibiotic therapy can remove normal microbiota which gives ability for pathogenic bacteria
such as C. difficile to invade
23.d Summarize the differences between innate immunity and adaptive immunity.
Innate immunity involves both chemical and physical barriers to infection and
relatively nonspecific responses that are meant to destroy foreign substances or cells. The
nonspecific responses recognize common microbial molecular patterns such as peptidoglycan
and lipopolysaccharides which are not found in host cells.
*Components of the innate immune response are found at birth*
Adaptive immunity involves reactions to specific antigens when the human body is exposed to
them. The adaptive component of the immune system retains memory of and can recognize
over 10^10 antigenic structures which allows for a faster response if exposed to them a second
time.
23.e Contrast the activities of a neutrophil, macrophage, and dendritic cells.
Neutrophils are cells that make up the vast majority of white cells in the blood and can engulf
microbes by phagocytosis --->
1. Phagocytic cell uses pseudopods to envelop the pathogen
2. Pathogen ends up in a phagosome vacuole
3. Phagocyte kills the organism by fusing enzyme-gorged lysosomes with the phagosome
100% CORRECT ANSWERS
23.a Identify areas of the human body colonized by microbes and areas that remain sterile;
explain why there are different types of microbes in the microbiota of different areas of the
body.
Areas of the body that are colonized by microbes:
Skin
-Mostly gram-positive species such as Staphylococcus epidemidis, Bacillus species,
and Propionibacterium ances
Oral & nasal cavities
-Non-pathogenic Neisseria, Streptococcus, Actinomyces, Lactobacillus, Treponema denticola,
Porphyromonas gingivalis, Streptococcus mutans, Streptococcus salivaeris
Respiratory tract (lungs and trachea)
Urethra
-Staphylococcus epidermidis, Entercoccus sp.
Bladder
-Some anaerobes
Vagina
-Lactobacillus, Firmicutes, yeasts
Stomach
-Only few microbes like H. pylori can survive
Intestines
-Many species of bacteria in feces; most notably E. coli and Bacteroides thetaiotaomicron
23.a Identify areas of the human body colonized by microbes and areas that remain sterile;
explain why there are different types of microbes in the microbiota of different areas of the
body.
Areas of the body that remain sterile:
-Kidneys
,-Ureters
-Heart
-Blood
-Cerebrospinal fluid
23.a Identify areas of the human body colonized by microbes and areas that remain
sterile; explain why there are different types of microbes in the microbiota of different areas
of the body.
There are different types of microbes on different areas of the body due to the fact that each
area has vastly different environmental factors that affect a microbe's ability to persist. Some
bacteria are better equipped to survive in different areas than others. Such conditions include:
-Moisture levels
-pH
-Temperature
-Salinity
-Competition with other bacterial species
-Energy source availability
-Enzymes that prevent growth
23.b Explain the hygiene hypothesis.
Hygiene hypothesis- exposure to more microbes and other environmental antigens early in life
may produce a more tolerant, well-controlled immune system that is less prone to inflammatory
and autoimmune diseases.
-Today we have more restricted access to microbes that are helpful in training our immune
system due to indoor living and using of antimicrobials
23.c Explain the benefits of gut microbiota and contrast that to when the microbiota moves
beyond the gut or comes into imbalance (give specific examples for beneficial microbes and
diseases that result from dysbiosis
Benefits of the gut microbiota:
-Commensal microbes make vitamins (E. coli makes B12) and catabolize the foods we eat
(Bacteroides thetaiotaomicron breaks down complex carbohydrates)
-Commensal organisms also prevent colonization by pathogens---> they are competitors for
food and space that is needed for attachment and growth; can also secrete toxins that kill other
bacteria (E. coli produces bacteriocin)
, -These organisms promote development of a healthy immune system and regulate the immune
response in the gut (some can reduce inflammation such as Bacteroides
fragilis and Faecalibacterium prausnitzii)
-The gut-brain axis has bidirectional signaling between the gut and brain that can affect
behavior and mood
23.c Explain the benefits of gut microbiota and contrast that to when the microbiota moves
beyond the gut or comes into imbalance (give specific examples for beneficial microbes and
diseases that result from dysbiosis
Harms from moving beyond the gut:
-Bacteroides fragilis can invade tissues through surgical wounds and cause abcesses or
gangrene
-Other issues such as UTIs, septicemia, and meningitis can occur
Dysbiosis (imbalance in microbial composition):
-Can occur through changes in diet, emotional stress, or antibiotic therapy
-Antibiotic therapy can remove normal microbiota which gives ability for pathogenic bacteria
such as C. difficile to invade
23.d Summarize the differences between innate immunity and adaptive immunity.
Innate immunity involves both chemical and physical barriers to infection and
relatively nonspecific responses that are meant to destroy foreign substances or cells. The
nonspecific responses recognize common microbial molecular patterns such as peptidoglycan
and lipopolysaccharides which are not found in host cells.
*Components of the innate immune response are found at birth*
Adaptive immunity involves reactions to specific antigens when the human body is exposed to
them. The adaptive component of the immune system retains memory of and can recognize
over 10^10 antigenic structures which allows for a faster response if exposed to them a second
time.
23.e Contrast the activities of a neutrophil, macrophage, and dendritic cells.
Neutrophils are cells that make up the vast majority of white cells in the blood and can engulf
microbes by phagocytosis --->
1. Phagocytic cell uses pseudopods to envelop the pathogen
2. Pathogen ends up in a phagosome vacuole
3. Phagocyte kills the organism by fusing enzyme-gorged lysosomes with the phagosome
