MICR 2420 Final Exam QUESTIONS AND
CORRECT ANSWERS
How does the microbiota protect us? (4) - CORRECT ANSWER -Competitive exclusion
(colonize of good bacteria to prevent growth of pathogen- niche filled)
-modify environment (change ph etc)
-Stimulate host immune system (stimulate cytokines)
-Direct pacification (secrete factors that tell the pathogen not to be pathogenic)
Name the two parts of the immune system - CORRECT ANSWER Innate Immune System
(born with)
Adaptive Immune System (adapts over time)
To show disease a pathogen must: (3) - CORRECT ANSWER 1) breach physical defense
2) Survive chemical response form Innate Immune System
3) Multiply
What are the primary lymphoid organs and what to they do? - CORRECT ANSWER Bone
marrow and thymus, where lymph cells are made
What are the secondary lymphoid organs and what do they do? - CORRECT ANSWER Lymph
nodes, appendix, spleen etc and they are stations for sampling for antigen presence
Name the 3 ways the complement system can be activated and from which immune system they
originate - CORRECT ANSWER 1) Classical pathway (adaptive)
2) Lectin pathway (adaptive)
3) Alternative pathways (innate)
Describe the alternative pathway - CORRECT ANSWER C3 cleaves into C3a and c3b, if C3b
meets a pathogen it will bind to factor B and be cleaved into c3bbb-->which become C5-->which
cleaves into c5a and c5b, C5b recruits and binds to c6 and c7 to form MAC (forms a pore on pathogen
so it's insides bleed out)
, What are cytokines? - CORRECT ANSWER Molecules secreted by cells that allow for
communication between cells, can be pro/anti inflammatory
What are defensins? Where do they mostly exist? - CORRECT ANSWER Antimicrobial
peptides that can lyse pathogens (like mace). Mostly exist in lower crypt of epithelial cells of gut
lining, in case a pathogen breaches the epithelial cells, defensins will spray their mace!
What stem cells make mast cells, phagocytes, neutrophils, maceophages and dendritic cells? -
CORRECT ANSWER Myeloid stem cells
What stem cells make b-cells and t-cells? - CORRECT ANSWER Lymphoid stem cells
Describe neutrophils and what they do (attack chihuaha) - CORRECT ANSWER -small,
numerous, first response white blood cell, make antimicrobial NET compounds to trap and degrade
bacteria.
-can also ingest and lyse bacterial cell (phagocytosis)
Possible problems with nets? (2) - CORRECT ANSWER -If we make too many we have
autoimmune disorder lupus
-some bacteria have slimy encapsulation and can slip out
Describe macrophages and what they do (rottweiler) - CORRECT ANSWER Large cells that
can consume many bacteria, don't die after (phagocytosis), become macrophage on the way to the
infection
Why can't macrophages exist as such while circulating in the body? - CORRECT
ANSWER Because they themselves secrete cytokines which if those cytokines were circulating
your whole body would think it's under attack
Describe dendrocytes (3 headed dog) - CORRECT ANSWER Another phagocyte, has
protrusions to fit between tight spaces and sample for antigens, hunt them before they're pathogenic
What cells are apcs? What does this mean? - CORRECT ANSWER Macrophages and
dendrocytes are antigen presenting cells, they display the antigen on them after ingestion for T-cells to
recognize
CORRECT ANSWERS
How does the microbiota protect us? (4) - CORRECT ANSWER -Competitive exclusion
(colonize of good bacteria to prevent growth of pathogen- niche filled)
-modify environment (change ph etc)
-Stimulate host immune system (stimulate cytokines)
-Direct pacification (secrete factors that tell the pathogen not to be pathogenic)
Name the two parts of the immune system - CORRECT ANSWER Innate Immune System
(born with)
Adaptive Immune System (adapts over time)
To show disease a pathogen must: (3) - CORRECT ANSWER 1) breach physical defense
2) Survive chemical response form Innate Immune System
3) Multiply
What are the primary lymphoid organs and what to they do? - CORRECT ANSWER Bone
marrow and thymus, where lymph cells are made
What are the secondary lymphoid organs and what do they do? - CORRECT ANSWER Lymph
nodes, appendix, spleen etc and they are stations for sampling for antigen presence
Name the 3 ways the complement system can be activated and from which immune system they
originate - CORRECT ANSWER 1) Classical pathway (adaptive)
2) Lectin pathway (adaptive)
3) Alternative pathways (innate)
Describe the alternative pathway - CORRECT ANSWER C3 cleaves into C3a and c3b, if C3b
meets a pathogen it will bind to factor B and be cleaved into c3bbb-->which become C5-->which
cleaves into c5a and c5b, C5b recruits and binds to c6 and c7 to form MAC (forms a pore on pathogen
so it's insides bleed out)
, What are cytokines? - CORRECT ANSWER Molecules secreted by cells that allow for
communication between cells, can be pro/anti inflammatory
What are defensins? Where do they mostly exist? - CORRECT ANSWER Antimicrobial
peptides that can lyse pathogens (like mace). Mostly exist in lower crypt of epithelial cells of gut
lining, in case a pathogen breaches the epithelial cells, defensins will spray their mace!
What stem cells make mast cells, phagocytes, neutrophils, maceophages and dendritic cells? -
CORRECT ANSWER Myeloid stem cells
What stem cells make b-cells and t-cells? - CORRECT ANSWER Lymphoid stem cells
Describe neutrophils and what they do (attack chihuaha) - CORRECT ANSWER -small,
numerous, first response white blood cell, make antimicrobial NET compounds to trap and degrade
bacteria.
-can also ingest and lyse bacterial cell (phagocytosis)
Possible problems with nets? (2) - CORRECT ANSWER -If we make too many we have
autoimmune disorder lupus
-some bacteria have slimy encapsulation and can slip out
Describe macrophages and what they do (rottweiler) - CORRECT ANSWER Large cells that
can consume many bacteria, don't die after (phagocytosis), become macrophage on the way to the
infection
Why can't macrophages exist as such while circulating in the body? - CORRECT
ANSWER Because they themselves secrete cytokines which if those cytokines were circulating
your whole body would think it's under attack
Describe dendrocytes (3 headed dog) - CORRECT ANSWER Another phagocyte, has
protrusions to fit between tight spaces and sample for antigens, hunt them before they're pathogenic
What cells are apcs? What does this mean? - CORRECT ANSWER Macrophages and
dendrocytes are antigen presenting cells, they display the antigen on them after ingestion for T-cells to
recognize
