BIOL371 INNATE DEFENSES EXAM QUESTIONS AND ANSWERS
WITH COMPLETE SOLUTIONS VERIFIED GRADED A++
What are innate defenses?
General resistance against antigens, but do not adapt to pathogen exposure.
What are primary defenses?
Physical and chemical surface barriers (think early infection)
Provide examples of physical barriers.
Skin, tears, saliva, mucus, cough, urine, ciliated expulsion
Provide examples of chemical barriers.
Stomach acid, mucus, lysozyme
How does stomach acid act as a chemical barrier?
Digests pathogens in food
How does mucus act as a chemical barrier?
Mucus is made up of soluble glycoproteins that protect epithelial cells and other
membranes.
How do lysozymes act as a chemical barrier?
They are enzymes produced by mucous membranes and lyse the NAM-NAG glycosidic
bond of peptidoglycan
Provide examples of mucous membranes.
Eyes & saliva.
What is microbial defense?
, The normal flora (probiotics) competing with pathogens for the host.
What are probiotics?
Living microbes that provide health benefits in the body.
What are bacteriocins?
Plasmid-encoded toxic proteins produced by normal microbiota. They are lethal to
pathogens.
What are secondary defenses?
A part of the immune system that recognizes and attacks pathogens. Non-specific to
pathogens and MUST be switched on by microbial challenge.
How does the body respond to bodily harm?
Inflammation, vascular dilation, and mobilization of phagocytic cells.
Describe inflammation.
A vascular response to injury.
What are signs of inflammation?
Redness, swelling, warmness, pain
Describe vascular dilation (from histamines)
It is increased vascular permeability leakage (edema/swelling)
Describe phagocytosis.
White blood cells (leukocytes) in capillaries squeeze through capillary walls to tissues in
order to eat dead tissues and pathogens (phagocytosis)
Describe the mechanism behind the body discerning self vs foreign.
The body has an innate surveillance system that recognizes common microbial
components
WITH COMPLETE SOLUTIONS VERIFIED GRADED A++
What are innate defenses?
General resistance against antigens, but do not adapt to pathogen exposure.
What are primary defenses?
Physical and chemical surface barriers (think early infection)
Provide examples of physical barriers.
Skin, tears, saliva, mucus, cough, urine, ciliated expulsion
Provide examples of chemical barriers.
Stomach acid, mucus, lysozyme
How does stomach acid act as a chemical barrier?
Digests pathogens in food
How does mucus act as a chemical barrier?
Mucus is made up of soluble glycoproteins that protect epithelial cells and other
membranes.
How do lysozymes act as a chemical barrier?
They are enzymes produced by mucous membranes and lyse the NAM-NAG glycosidic
bond of peptidoglycan
Provide examples of mucous membranes.
Eyes & saliva.
What is microbial defense?
, The normal flora (probiotics) competing with pathogens for the host.
What are probiotics?
Living microbes that provide health benefits in the body.
What are bacteriocins?
Plasmid-encoded toxic proteins produced by normal microbiota. They are lethal to
pathogens.
What are secondary defenses?
A part of the immune system that recognizes and attacks pathogens. Non-specific to
pathogens and MUST be switched on by microbial challenge.
How does the body respond to bodily harm?
Inflammation, vascular dilation, and mobilization of phagocytic cells.
Describe inflammation.
A vascular response to injury.
What are signs of inflammation?
Redness, swelling, warmness, pain
Describe vascular dilation (from histamines)
It is increased vascular permeability leakage (edema/swelling)
Describe phagocytosis.
White blood cells (leukocytes) in capillaries squeeze through capillary walls to tissues in
order to eat dead tissues and pathogens (phagocytosis)
Describe the mechanism behind the body discerning self vs foreign.
The body has an innate surveillance system that recognizes common microbial
components
