BIO 175 Exam 3 Questions with Complete
Solutions
Antiphagocytic Factors The pathogen has antiphagocytic factors to resist being engulfed
and destroyed.
Leukoocidins -chemicals that will destroy the WBC that ingest the pathogen -Avoidance
of destructions = some pathogens will survive phagocytosis to hide, grow, and spread throughout
the host body. Chemicals that can prevent the fusion of the lysosome and the phagocytic vesicles
so that the bacteria is ingested but not digested
Germ Theory of Disease by Robert Koch Set of postulates to prove that a pathogen can
cause a disease
Stages of Infectious Disease 1. Incubation period = no signs or symptoms. From initial
contact to first signs of the infection
2. Prodromal period = short stage with general symptoms.
3. Illness (period of invasion)= severe signs and symptoms with the greatest toxicity. If this stage
persists, then death of host may occur.
4. Decline = declining signs and symptoms
,5. Convalescence = recovery or healing with no signs or symptoms. Immune response is strong
and active.
Communicable The ability of a disease-causing organism to be spread between
individuals
Portals of Exit -Respiratory and salivary portals = mainly coughing or sneezing but also
though talking and laughing will release particles in the air that can contain the infectious agents
-Skin= shedding of the outer layers of the skin may also allow the pathogen to leave the host and
spread to others
-Defecation = pathogens in feces may find their way into crops and water to infect others
-Urogenital tract = sexually transmitted infections are spread through vaginal discharge and
semen. There is a lower possibility of pathogens that infect the kidneys exiting through the urine.
-Bleeding = blood-feeding animals such as ticks can become transmitter of the pathogenic
microbe. Sharing needles or small gashes of the mucous membrane during sexual intercourse can
also allow the pathogen to leave the host and spread.
, Resevoirs -the natural primary habitat of the pathogen
-Source = the individual or object where the infection was acquired
Living Reservoirs -Carriers = individual who inconspicuously shelters a pathogen and
spread it to others without any notice
Humans
>Asymptomatic carriers who will never so the symptoms but are infected
>Incubating carriers who can spread the pathogen during the incubation period of an infection
>Convalescent carriers are people who are in the recovery stage but will continue to shed the
pathogen and the infection to others
>Chronic carriers are people who shelter the pathogen for a long period even after recovery
>Passive carriers are people who work in the medical and dental field. They will be in continous
contact with patients' secretions and blood and may accidentally transfer to other patients. Proper
aseptic techniques are essential for reducing the spread.
Solutions
Antiphagocytic Factors The pathogen has antiphagocytic factors to resist being engulfed
and destroyed.
Leukoocidins -chemicals that will destroy the WBC that ingest the pathogen -Avoidance
of destructions = some pathogens will survive phagocytosis to hide, grow, and spread throughout
the host body. Chemicals that can prevent the fusion of the lysosome and the phagocytic vesicles
so that the bacteria is ingested but not digested
Germ Theory of Disease by Robert Koch Set of postulates to prove that a pathogen can
cause a disease
Stages of Infectious Disease 1. Incubation period = no signs or symptoms. From initial
contact to first signs of the infection
2. Prodromal period = short stage with general symptoms.
3. Illness (period of invasion)= severe signs and symptoms with the greatest toxicity. If this stage
persists, then death of host may occur.
4. Decline = declining signs and symptoms
,5. Convalescence = recovery or healing with no signs or symptoms. Immune response is strong
and active.
Communicable The ability of a disease-causing organism to be spread between
individuals
Portals of Exit -Respiratory and salivary portals = mainly coughing or sneezing but also
though talking and laughing will release particles in the air that can contain the infectious agents
-Skin= shedding of the outer layers of the skin may also allow the pathogen to leave the host and
spread to others
-Defecation = pathogens in feces may find their way into crops and water to infect others
-Urogenital tract = sexually transmitted infections are spread through vaginal discharge and
semen. There is a lower possibility of pathogens that infect the kidneys exiting through the urine.
-Bleeding = blood-feeding animals such as ticks can become transmitter of the pathogenic
microbe. Sharing needles or small gashes of the mucous membrane during sexual intercourse can
also allow the pathogen to leave the host and spread.
, Resevoirs -the natural primary habitat of the pathogen
-Source = the individual or object where the infection was acquired
Living Reservoirs -Carriers = individual who inconspicuously shelters a pathogen and
spread it to others without any notice
Humans
>Asymptomatic carriers who will never so the symptoms but are infected
>Incubating carriers who can spread the pathogen during the incubation period of an infection
>Convalescent carriers are people who are in the recovery stage but will continue to shed the
pathogen and the infection to others
>Chronic carriers are people who shelter the pathogen for a long period even after recovery
>Passive carriers are people who work in the medical and dental field. They will be in continous
contact with patients' secretions and blood and may accidentally transfer to other patients. Proper
aseptic techniques are essential for reducing the spread.
