Questions and Answers
What is the primary requirement for a pathogen to cause disease?
Which of the following is NOT a type of portal of entry?
What is the term for an encounter with a potential pathogen?
Which of the following is a major portal of entry that is only present during pregnancy?
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What is the primary location where mucosal surfaces are found?
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What is the term for the process by which a pathogen establishes an infection?
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Which of the following is a characteristic of most pathogens?
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What is the term for the stage of pathogenesis where the pathogen causes damage to the host?
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Which of the following best describes the primary routes through which pathogens can enter the body?
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What distinguishes parenteral entry of pathogens from other entry routes?
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Which statement regarding the placenta as a barrier to pathogens is correct?
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Which group of pathogens is collectively known by the acronym TORCH?
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Why are infants given antibiotic drops in their eyes shortly after birth?
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What role do enzymes and toxins secreted by pathogens play in their ability to infect?
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Which of the following pathogens is known to cause listeriosis and poses a risk to fetuses?
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In terms of portal entry for pathogens, what role does the respiratory tract play?
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What happens when one drug or substance reduces or negates the effect of another?
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What is the outcome when a drug causes harmful or damaging effects to the body?
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What is the term for when a drug or combination of drugs causes death or has fatal consequences?
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What type of effect occurs when the combined use of two drugs enhances their therapeutic effect and allows for lower doses?
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Which of the following effects results in a more effective treatment at lower doses?
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What is the opposite of a synergistic effect in the context of drug interactions?
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Study Notes
Stages of Pathogenesis
- Pathogens must successfully complete four stages to cause disease: exposure (contact), adhesion (colonization), invasion, and infection
- The pathogen must gain entry to the host, travel to the infection site, evade/overcome the host's immune response, and cause damage to the host
- In many cases, the cycle is completed when the pathogen exits the host and is transmitted to a new host
Exposure (Contact)
- Exposure occurs when a host encounters a potential pathogen through food, objects, or other means
- Not all contacts result in infection and disease
- A pathogen must gain access to host tissue through a portal of entry
Portals of Entry
- Portals of entry are anatomic sites where pathogens can pass into host tissue
- Examples of portals of entry include:
- Skin
- Mucous membranes
- Parenteral routes (e.g., needle, broken skin, insect bite)
- Eye (conjunctiva)
- Nose
- Mouth
- Ear
- Urethra
- Vagina
- Anus
- Placenta (during pregnancy)
- Mucosal surfaces are the most important portals of entry for microbes
- Pathogens are often suited to a particular portal of entry based on environmental adaptations and secreted enzymes/toxins
Specific Portals of Entry
- Respiratory and gastrointestinal tracts are particularly vulnerable due to constant inhalation/ingestion of particles containing microorganisms
- Breaches in skin and mucous membranes can provide a parenteral portal of entry
- Placenta normally prevents microorganisms from passing from pregnant person to fetus, but some pathogens (e.g., Listeria monocytogenes, TORCH infections) can cross the blood-placental barrier
TORCH Infections
- TORCH infections are pathogens that can cross the placental barrier to infect the fetus
- Examples of TORCH infections include:
- Toxoplasmosis (Toxoplasma gondii)
- Syphilis (Treponema pallidum)
- Chickenpox (Varicella-zoster virus)
- Hepatitis B (Hepatitis B virus)
- HIV (Retrovirus)
- Fifth disease (Parvovirus B19)
- Rubella (German measles, Togavirus)
Pharmacological Interactions
- Antagonistic Effect: When one drug or substance reduces or negates the effect of another.
Incorrect Options
- Toxic Effect: A drug causes harmful or damaging effects to the body, often at higher doses or adverse interactions.
- Lethal Effect: A drug or combination of drugs causes death or has fatal consequences.
Synergistic Effect
- Definition: When the combined use of two drugs enhances their therapeutic effect.
- Characteristics: Allows for lower doses, making treatment more effective and potentially safer.
- Scenario: The combination of two drugs results in a more effective treatment at lower doses.
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Description
Understand the four stages of pathogenesis, from exposure to infection, and how pathogens cause disease in hosts.
