Infectious Diseases and the Immune System

Comprehensive practice flashcards covering pathogens, lines of immune defense, viral replication, bacterial classification, and vaccination based on lecture materials.

What is the definition of a disease?

A disease is a condition that harms the body from functioning properly.

What is the difference between communicable and non-communicable diseases, and what is an example of each?

Communicable diseases spread directly from person to person (such as through skin-to-skin contact or droplet spread), whereas non-communicable diseases are not spreadable from person to person (for example, cancer).

What is the definition of a pathogen?

A pathogen is an agent that is capable of causing disease or illness.

Are bacteria, viruses, and prions considered living or non-living pathogens, and what is an example of each?

Bacteria are living (e.g., Tuberculosis), viruses are non-living (e.g., Covid-19), and prions are non-living (e.g., mad cow disease).

Why are bacteria classified as living pathogens?

Bacteria are considered living because they are made of cells.

What is the difference between normal flora bacteria and pathogenic bacteria?

Normal flora bacteria do not cause disease and help the body, while pathogenic bacteria cause disease and harm the body.

Under what conditions can normal flora bacteria become pathogenic?

Normal flora can become pathogenic when the immune system is weakened, causing the body to lose control over the normal flora.

What mode of transmission occurs when an individual contracts an illness from someone sneezing directly near them?

Droplet spread, which is a form of direct transmission.

What are two risks associated with the use of antibiotics?

Antibiotics may cause side effects in the body, and they might fail to work on the pathogens.

What are anaerobic bacteria, and where does Actinomyces typically cause infection?

Anaerobic bacteria are bacteria that do not require oxygen to survive and can be harmed by it; Actinomyces is an anaerobic bacteria that most commonly causes infections affecting the face and neck.

What morphological shape characterizes Actinomyces bacteria?

Actinomyces is a bacilli (rod-shaped) bacteria.

What are the four primary structural components of an enveloped virus?

Envelope, envelope protein, capsid, and genetic material.

What are the five steps involved in viral replication inside a host cell?

1. Attaches to a host cell. 2. Enters the host cell/nucleus and releases genetic material. 3. Takes over the host cell and makes viral particles. 4. Replicates itself using the hijacked host cell until the cell bursts and releases viruses. 5. Cycle repeats for other host cells.

How are innate, adaptive, and passive immunity defined, and what is an example of each?

Innate immunity is an immediate, non-specific defense (e.g., first and second lines of defense, skin); adaptive immunity is a specific, long-term defense (e.g., third line of defense); passive immunity is a borrowed defense (e.g., antibodies transferred through breast milk).

What are two main structures of the first line of defence, and how does a cut compromise this line?

Structures include the skin, hair, and mucous layers; a cut compromises the first line of defence by destroying the physical barrier of the skin.

Which line of defence includes inflammation, and what are its key characteristics?

Inflammation is part of the second line of defence; its characteristics include an influx of blood and white cells, redness, swelling, and pain.

Why is the third line of defence characterized as slow-acting and specific?

It does not react immediately because it identifies specific pathogens before attacking and responds differently to each pathogen, which takes time.

What are two types of cells involved in the third line of defence and their respective functions?

B cells produce antibodies, while T cells coordinate the immune system response and attack infected cells.

What are antibodies and how do they combat pathogens?

Antibodies are proteins that fight off pathogens by tagging onto them (such as bacteria) to mark them for destruction.

What diseases does the MMR vaccine protect against, and what is its standard dosage schedule?

It protects against measles, mumps, and rubella. The first dose is typically given at 9 to 15 months of age, followed by a second dose at 15 months to 6 years of age, with at least 4 weeks between doses.

Is vaccination an example of natural or artificial immunity, and how does it establish protection?

Vaccination is artificial immunity. It introduces a weaker, harmless version of the pathogen so the immune system can recognize it, practice fighting it, and create immunological memory to respond more strongly upon future exposure.

What are the benefits of memory T and B cells, and what are two main ways to control the spread of a new disease?

Memory cells recognize past diseases and fight them off faster. Spread of a new disease can be controlled through high vaccination rates and avoiding contact to prevent direct transmission.