BMS 127 Midterm 3 Exam Questions With
Complete Answers
What are the three lines of immunological defense? - ANSWER 1. Exterior defenses
2. Phagocytosis & inflammation
3. Adaptive immunity
Which of the immunological defenses are nonspecific? - ANSWER Exterior defenses and
phagocytosis & inflammation
Which of the immunological defenses are considered innate immunity? - ANSWER Exterior
defenses and phagocytosis & inflammation
In general, what do the exterior defenses entail? - ANSWER Mechanical, chemical and
microbial barriers
What is the most common way that pathogens enter the body? - ANSWER The respiratory
tract
Define the sum of our resident microbiota - ANSWER Microbiome
What is microbial antagonism? - ANSWER The out-competition of transient microbes by our
,resident microbiota
How does the body handle transient microbes that have reached the trachea? - ANSWER
Through the mucociliary system where there are ciliated and non-ciliated cells that create
mucus. This causes a constant upward motion of mucus into the pharynx to either cough up
or swallow.
How do the eyes play a role in the external defenses? - ANSWER Tears contain lysozymes that
dissolve cell walls by destroying peptidoglycan
How does the mouth play a role in exterior defenses? - ANSWER Each tooth has its own
microbial background of residential microbiota
How does the skin play a role in exterior defenses? - ANSWER Skin acts as a physical barrier
against pathogens. It also produces anti microbial fatty acids, and it's residential microbiota
inhibit pathogen colonization
How does the stomach play a role in exterior defenses? - ANSWER Stomach acid has a pH of 2
which very few microbes can survive. Plus the rapid pH change from the stomach to the
duodenum from the gallbladder's release of bile salts makes it even harder for microbes to
survive.
How does the urinary system play a role in exterior defenses? - ANSWER The "fast flow," of
urine helps flush out any pathogens from the urinary tract
, How does pooping play a role in exterior defenses? - ANSWER It gets rid of pathogens from
the large intestine
How does the upper respiratory system play a role in exterior defenses? - ANSWER Rapid
passage of air over cilia in the nasopharynx allows pathogens to get trapped in the mucus and
coughed up or swallowed
How does the blood play a role in exterior defenses? - ANSWER There are proteins in the
blood that can inhibit microbial growth
How do the lungs play a role in exterior defenses? - ANSWER There is one phagocyte per
alveolus in the lungs
How does the small intestine play a role in exterior defenses? - ANSWER The small intestine
contains most of our residential microbiota due to the neutral pH, and microbial antagonism
will also take place here
Why can't children under the age of 1 eat honey? - ANSWER Honey often contains botulism
spores that infants' GI tracts are unable to compete with since they haven't established a
robust enough residential microbiome
It is estimated that the _______ line of defense, AKA ________ alone protects us from _______% of
pathogens everyday - ANSWER first line of defense, exterior defenses, 99%
Complete Answers
What are the three lines of immunological defense? - ANSWER 1. Exterior defenses
2. Phagocytosis & inflammation
3. Adaptive immunity
Which of the immunological defenses are nonspecific? - ANSWER Exterior defenses and
phagocytosis & inflammation
Which of the immunological defenses are considered innate immunity? - ANSWER Exterior
defenses and phagocytosis & inflammation
In general, what do the exterior defenses entail? - ANSWER Mechanical, chemical and
microbial barriers
What is the most common way that pathogens enter the body? - ANSWER The respiratory
tract
Define the sum of our resident microbiota - ANSWER Microbiome
What is microbial antagonism? - ANSWER The out-competition of transient microbes by our
,resident microbiota
How does the body handle transient microbes that have reached the trachea? - ANSWER
Through the mucociliary system where there are ciliated and non-ciliated cells that create
mucus. This causes a constant upward motion of mucus into the pharynx to either cough up
or swallow.
How do the eyes play a role in the external defenses? - ANSWER Tears contain lysozymes that
dissolve cell walls by destroying peptidoglycan
How does the mouth play a role in exterior defenses? - ANSWER Each tooth has its own
microbial background of residential microbiota
How does the skin play a role in exterior defenses? - ANSWER Skin acts as a physical barrier
against pathogens. It also produces anti microbial fatty acids, and it's residential microbiota
inhibit pathogen colonization
How does the stomach play a role in exterior defenses? - ANSWER Stomach acid has a pH of 2
which very few microbes can survive. Plus the rapid pH change from the stomach to the
duodenum from the gallbladder's release of bile salts makes it even harder for microbes to
survive.
How does the urinary system play a role in exterior defenses? - ANSWER The "fast flow," of
urine helps flush out any pathogens from the urinary tract
, How does pooping play a role in exterior defenses? - ANSWER It gets rid of pathogens from
the large intestine
How does the upper respiratory system play a role in exterior defenses? - ANSWER Rapid
passage of air over cilia in the nasopharynx allows pathogens to get trapped in the mucus and
coughed up or swallowed
How does the blood play a role in exterior defenses? - ANSWER There are proteins in the
blood that can inhibit microbial growth
How do the lungs play a role in exterior defenses? - ANSWER There is one phagocyte per
alveolus in the lungs
How does the small intestine play a role in exterior defenses? - ANSWER The small intestine
contains most of our residential microbiota due to the neutral pH, and microbial antagonism
will also take place here
Why can't children under the age of 1 eat honey? - ANSWER Honey often contains botulism
spores that infants' GI tracts are unable to compete with since they haven't established a
robust enough residential microbiome
It is estimated that the _______ line of defense, AKA ________ alone protects us from _______% of
pathogens everyday - ANSWER first line of defense, exterior defenses, 99%
