Mod. 1 Immunity Flashcards
pyrogens, interferons, complement proteins, and concepts of required immunity
Which of the following molecules is primarily responsible for inducing fever and systemic inflammatory responses to bacterial infections?
A) Pyrogens
B) Interferons
C) Neutrophils
D) Complement proteins
A) Pyrogens
Rationale: Pyrogens, released by bacteria or in response to infection, cause fever by triggering a systemic inflammatory response. This response creates an environment that is less favorable for bacterial growth, making it a key defense mechanism.
Which element do bacteria require for reproduction that is removed from the blood by the spleen and liver during a mild fever?
A) Iron
B) Oxygen
C) Calcium
D) Nitrogen
A) Iron
Rationale: During a mild fever, the body lowers iron levels in the blood as bacteria need iron to replicate. The spleen and liver remove iron to create an environment that inhibits bacterial growth.
Which of the following best describes the role of interferons in the immune response to viral infections?
A) They directly kill virus-infected cells
B) They bind to uninfected cells, prompting them to release enzymes that prevent viral replication
C) They activate B-cells to produce antibodies
D) They enhance the effects of complement proteins in antigen destruction
B) They bind to uninfected cells, prompting them to release enzymes that prevent viral replication
Rationale: Interferons are released by virus-infected cells and bind to uninfected cells, triggering them to release enzymes that prevent the replication of the virus, providing a defense against viral spread.
Complement proteins are involved in the immune response. Which of the following best describes their function?
A) They destroy pathogens directly by phagocytosis
B) They enhance antibody activity and play a role in immune and inflammatory responses
C) They neutralize viruses before they infect host cells
D) They produce antibodies to fight bacterial infections
B) They enhance antibody activity and play a role in immune and inflammatory responses
Rationale: Complement proteins are plasma proteins that enhance the activity of antibodies and are involved in both immune and inflammatory responses. They also help in opsonization, drawing white blood cells to the infection site to “eat” bacteria.
What process does opsonization refer to in the immune response?
A) The direct destruction of infected cells by cytotoxic T-cells
B) The formation of antigen-antibody complexes that trigger complement activation
C) The process where white blood cells are drawn to the infected area to engulf and destroy bacteria
D) The release of interferons to inhibit viral replication
C) The process where white blood cells are drawn to the infected area to engulf and destroy bacteria
Rationale: Opsonization involves the marking of pathogens by antibodies or complement proteins, which enhances their recognition by white blood cells, prompting phagocytosis.
What is the primary function of T-helper (Th) cells in cellular immunity?
A) They directly kill infected cells
B) They regulate and assist other immune cells, including B-cells and cytotoxic T-cells
C) They produce antibodies against pathogens
D) They suppress immune responses to prevent overactivation
B) They regulate and assist other immune cells, including B-cells and cytotoxic T-cells
Rationale: T-helper cells (CD4+ T-cells) are crucial for regulating the immune response. They help activate B-cells to produce antibodies and assist cytotoxic T-cells in killing infected cells.
Which of the following best describes the role of memory B-cells in humoral immunity?
A) They produce antibodies during the first exposure to an antigen
B) They are responsible for a quicker and stronger response to a subsequent exposure to the same antigen
C) They help regulate T-cell responses to infections
D) They are involved in the destruction of infected cells by phagocytosis
B) They are responsible for a quicker and stronger response to a subsequent exposure to the same antigen
Rationale: Memory B-cells remember previously encountered antigens and respond more rapidly and effectively upon re-exposure, providing long-lasting immunity.
In which type of immunity do B-cells produce antibodies after initial exposure to an antigen, and memory cells provide a quicker response in the future?
A) Innate immunity
B) Active acquired immunity
C) Passive acquired immunity
D) Humoral immunity
D) Humoral immunity
Rationale: Humoral immunity involves the production of antibodies by B-cells in response to antigen exposure. Memory B-cells are generated during the initial response and allow for a faster immune response upon subsequent exposures.
What is the main difference between active acquired immunity and passive acquired immunity?
A) Active acquired immunity provides temporary protection through transferred antibodies
B) Passive acquired immunity involves the body’s own immune system responding to pathogens
C) Active acquired immunity involves the production of antibodies by the body itself, while passive acquired immunity involves the transfer of antibodies from another source
D) Passive acquired immunity is longer-lasting than active acquired immunity
C) Active acquired immunity involves the production of antibodies by the body itself, while passive acquired immunity involves the transfer of antibodies from another source
Rationale: In active acquired immunity, the body produces its own antibodies in response to infection or vaccination. In passive acquired immunity, antibodies are transferred from another source, such as from mother to child through breastfeeding or through antibody therapy.
Which factor contributes to immune system changes during adolescence that may increase the risk for inflammatory and autoimmune diseases?
A) Decreased production of B- and T-cells
B) Hormonal changes that affect immune cell function
C) Decreased apoptosis of immune cells
D) A weaker response to vaccinations
B) Hormonal changes that affect immune cell function
Rationale: During adolescence, hormonal changes influence immune system function, and there may be an increased risk for inflammatory and autoimmune diseases due to these changes, as well as altered responses to infections and vaccinations.
In older adults, what impact does immune senescence have on the immune system?
A) Increased production of B- and T-cells
B) A stronger immune response to infections
C) A decreased immune response and increased apoptosis of immune cells
D) An improved ability to differentiate self from non-self
C) A decreased immune response and increased apoptosis of immune cells
Rationale: As individuals age, their immune system undergoes immune senescence, which is characterized by a decrease in the production of B- and T-cells and an increased rate of apoptosis (cell death), leading to a weakened immune response.
