Innate Immunity: Non-Specific Defenses of The Host

Flashcards covering key concepts from Chapter 16 on Innate Immunity, including definitions, mechanisms, and examples of the body's non-specific defenses.

What is the main function of the immune system?

To protect the human host from pathogens.

Define immunity.

The ability to fight off pathogens and prevent disease.

What distinguishes host resistance from host susceptibility?

Host resistance indicates the presence of immunity, while host susceptibility indicates a lack of immunity.

What are innate and adaptive immunity?

Innate immunity is non-specific and acts against all pathogens, while adaptive immunity is specific to particular pathogens.

List two characteristics of innate immunity.

1. It is present at birth. 2. It provides a rapid immune response.

What is adaptive immunity primarily characterized by?

Specific recognition and response to particular pathogens, along with immunological memory.

Name the first line of defense in innate immunity.

Physical barriers such as intact skin and mucous membranes.

What role do mucous membranes play in immune defense?

They secrete mucus to trap pathogens and line body cavities.

Explain the significance of the ciliary escalator in innate immunity.

It helps move mucus and trapped pathogens out of the respiratory tract.

What are lysozymes and where are they found?

Lysozymes are enzymes found in body secretions that break down bacterial cell walls.

Identify one mechanism by which normal microbiota contribute to host defense.

Competitive exclusion, where normal microbiota compete with pathogens for resources.

What is phagocytosis?

The ingestion of microbes or other substances by phagocytes.

List the phases of phagocytosis.

1. Chemotaxis 2. Adherence 3. Ingestion 4. Digestion.

How does inflammation serve as a second line of defense?

It attracts immune cells to the site of infection and helps eliminate pathogens.

What are the consequences of fever during an infection?

It increases metabolic rate, enhances immune response, and induces antimicrobial substances.

Define the complement system in the context of innate immunity.

A series of proteins in blood that enhance the immune response and help destroy pathogens.

Describe the role of interferons in the immune response.

They are proteins produced by infected cells that signal neighboring cells to heighten their antiviral defenses.

How can pathogens evade phagocytosis?

By using capsules, leukocidins, or mycolic acid to avoid detection and destruction.

What is the main function of the immune system?

To protect the human host from pathogens.

Define immunity.

The ability to fight off pathogens and prevent disease.

What distinguishes host resistance from host susceptibility?

Host resistance indicates the presence of immunity, while host susceptibility indicates a lack of immunity.

What are innate and adaptive immunity?

Innate immunity is non-specific and acts against all pathogens, while adaptive immunity is specific to particular pathogens.

List two characteristics of innate immunity.

1. It is present at birth. 2. It provides a rapid immune response.

What is adaptive immunity primarily characterized by?

Specific recognition and response to particular pathogens, along with immunological memory.

Name the first line of defense in innate immunity.

Physical barriers such as intact skin and mucous membranes.

What role do mucous membranes play in immune defense?

They secrete mucus to trap pathogens and line body cavities.

Explain the significance of the ciliary escalator in innate immunity.

It helps move mucus and trapped pathogens out of the respiratory tract.

What are lysozymes and where are they found?

Lysozymes are enzymes found in body secretions that break down bacterial cell walls.

Identify one mechanism by which normal microbiota contribute to host defense.

Competitive exclusion, where normal microbiota compete with pathogens for resources.

What is phagocytosis?

The ingestion of microbes or other substances by phagocytes.

List the phases of phagocytosis.

1. Chemotaxis 2. Adherence 3. Ingestion 4. Digestion.

How does inflammation serve as a second line of defense?

It attracts immune cells to the site of infection and helps eliminate pathogens.

What are the consequences of fever during an infection?

It increases metabolic rate, enhances immune response, and induces antimicrobial substances.

Define the complement system in the context of innate immunity.

A series of proteins in blood that enhance the immune response and help destroy pathogens.

Describe the role of interferons in the immune response.

They are proteins produced by infected cells that signal neighboring cells to heighten their antiviral defenses.

How can pathogens evade phagocytosis?

By using capsules, leukocidins, or mycolic acid to avoid detection and destruction.

What are leukocytes (white blood cells)?

Cells of the immune system involved in defending the body against both infectious disease and foreign materials.

Identify the primary function of neutrophils.

Phagocytosis; they are primary responders to infection and are highly active in ingesting bacteria and other pathogens.

What role do macrophages play in immunity?

They are powerful phagocytes that engulf pathogens, dead cells, and cellular debris. They also act as antigen-presenting cells (APCs) to initiate adaptive immune responses.

How do Natural Killer (NK) cells contribute to innate immunity?

They directly kill virus-infected cells and tumor cells without prior activation, by inducing apoptosis (programmed cell death).

What are the two main branches of adaptive immunity?

1. Humoral immunity. 2. Cell-mediated immunity.

What is humoral immunity primarily mediated by?

Antibodies (immunoglobulins) produced by B lymphocytes.

What is cell-mediated immunity primarily mediated by?

T lymphocytes (T cells), which directly attack infected cells or regulate other immune cells.

Define an antigen.

A substance (usually a protein or polysaccharide) that causes the body to produce a specific immune response, especially the production of antibodies.

Define an antibody (immunoglobulin).

A protein produced by B cells in response to an antigen, capable of binding specifically to that antigen to neutralize or eliminate it.

What is the main function of the immune system?

To protect the human host from pathogens.

Define immunity.

The ability to fight off pathogens and prevent disease.

What distinguishes host resistance from host susceptibility?

Host resistance indicates the presence of immunity, while host susceptibility indicates a lack of immunity.

What are innate and adaptive immunity?

Innate immunity is non-specific and acts against all pathogens, while adaptive immunity is specific to particular pathogens.

List two characteristics of innate immunity.

1. It is present at birth. 2. It provides a rapid immune response.

What is adaptive immunity primarily characterized by?

Specific recognition and response to particular pathogens, along with immunological memory.

Name the first line of defense in innate immunity.

Physical barriers such as intact skin and mucous membranes.

What role do mucous membranes play in immune defense?

They secrete mucus to trap pathogens and line body cavities.

Explain the significance of the ciliary escalator in innate immunity.

It helps move mucus and trapped pathogens out of the respiratory tract.

What are lysozymes and where are they found?

Lysozymes are enzymes found in body secretions that break down bacterial cell walls.

Identify one mechanism by which normal microbiota contribute to host defense.

Competitive exclusion, where normal microbiota compete with pathogens for resources.

What is phagocytosis?

The ingestion of microbes or other substances by phagocytes.

List the phases of phagocytosis.

1. Chemotaxis 2. Adherence 3. Ingestion 4. Digestion.

How does inflammation serve as a second line of defense?

It attracts immune cells to the site of infection and helps eliminate pathogens.

What are the consequences of fever during an infection?

It increases metabolic rate, enhances immune response, and induces antimicrobial substances.

Define the complement system in the context of innate immunity.

A series of proteins in blood that enhance the immune response and help destroy pathogens.

Describe the role of interferons in the immune response.

They are proteins produced by infected cells that signal neighboring cells to heighten their antiviral defenses.

How can pathogens evade phagocytosis?

By using capsules, leukocidins, or mycolic acid to avoid detection and destruction.

What are leukocytes (white blood cells)?

Cells of the immune system involved in defending the body against both infectious disease and foreign materials.

Identify the primary function of neutrophils.

Phagocytosis; they are primary responders to infection and are highly active in ingesting bacteria and other pathogens.

What role do macrophages play in immunity?

They are powerful phagocytes that engulf pathogens, dead cells, and cellular debris. They also act as antigen-presenting cells (APCs) to initiate adaptive immune responses.

How do Natural Killer (NK) cells contribute to innate immunity?

They directly kill virus-infected cells and tumor cells without prior activation, by inducing apoptosis (programmed cell death).

What are the two main branches of adaptive immunity?

1. Humoral immunity. 2. Cell-mediated immunity.

What is humoral immunity primarily mediated by?

Antibodies (immunoglobulins) produced by B lymphocytes.

What is cell-mediated immunity primarily mediated by?

T lymphocytes (T cells), which directly attack infected cells or regulate other immune cells.

Define an antigen.

A substance (usually a protein or polysaccharide) that causes the body to produce a specific immune response, especially the production of antibodies.

Define an antibody (immunoglobulin).

A protein produced by B cells in response to an antigen, capable of binding specifically to that antigen to neutralize or eliminate it.

What is the function of Eosinophils?

To combat multicellular parasites and certain infections, also involved in allergic reactions.

What is the role of Basophils and Mast cells?

They release histamine and other inflammatory mediators, playing a key role in allergic responses and inflammation.

What makes skin an effective physical barrier?

Its outermost layer composed of dead, tightly packed cells (keratinocytes) and its dry, acidic environment.

What is the difference between active and passive immunity?

Active immunity develops when a person's own immune system produces antibodies in response to an antigen, while passive immunity is acquired when a person receives antibodies from another source (e.g., mother to child, antibody injection).

What are pattern recognition receptors (PRRs)?

Receptors on immune cells that recognize conserved molecular patterns (PAMPs or DAMPs) associated with pathogens or cellular damage.

How does the lymphatic system contribute to immunity?

It transports lymph, contains immune cells (lymphocytes), filters