Innate Immunity Flashcards
What is innate immunity?
Innate immunity is the first line of defense against infections, providing immediate, non-specific responses to pathogens.
What are the main differences between innate and adaptive immunity?
Innate immunity is present at birth, non-specific, rapid, and lacks memory, while adaptive immunity is acquired, specific, slower, and has memory.
What are the primary physical barriers of innate immunity?
Skin, mucosal membranes, hair in the nose, saliva, tears, and gut microbiota.
What are the major cells involved in innate immunity?
Neutrophils, macrophages, monocytes, dendritic cells, natural killer (NK) cells, eosinophils, basophils, and mast cells.
What is the function of the complement system?
The complement system enhances phagocytosis, induces inflammation, and forms the membrane attack complex (MAC) to lyse pathogens.
Neutrophils are
the most abundant innate immune cells, making up 50-70% of white blood cells.
Macrophages act as
antigen-presenting cells and aid in tissue repair.
Pattern recognition receptors (PRRs) recognize
pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs).
The inflammatory response includes
redness (rubor), swelling (tumor), heat (calor), pain (dolor), and loss of function.
Natural killer (NK) cells target and kill
virus-infected and cancerous cells without prior sensitization.
Innate immunity provides a slow, antigen-specific response.
False
Macrophages can be tissue-resident and named based on location (e.g., Kupffer cells in the liver).
True
The complement system is exclusively part of adaptive immunity.
False
Eosinophils are important in fighting parasitic infections.
True
The four main signs of inflammation are ______________, ______________, ______________, and ______________.
Redness, swelling, heat, pain
Dendritic cells are professional ______________ cells that present antigens to T cells.
Antigen-presenting
The enzyme ______________ forms reactive oxygen species to kill pathogens in phagocytes.
NADPH oxidase
The process where immune cells move toward chemical signals at an infection site is called ______________.
Chemotaxis
Which of the following cells is NOT part of the innate immune system?
a) Macrophages
b) B cells
c) Neutrophils
d) Natural killer cells
Answer: (b) B cells
Which immune cell releases histamine and is involved in allergic responses?
a) Macrophages
b) Basophils
c) Neutrophils
d) Dendritic cells
Answer: (b) Basophils
What molecule enhances phagocytosis by marking pathogens for destruction?
a) Hemoglobin
b) Opsonins (e.g., C3b)
c) Insulin
d) MHC I
Answer: (b) Opsonins (e.g., C3b)
A patient has a bacterial infection, and their blood test shows an increase in neutrophil count. What does this indicate?
The innate immune system is actively responding to the infection, as neutrophils are the first responders to bacterial infections.
A person with a genetic defect in NADPH oxidase suffers from recurrent bacterial infections. What immune process is affected?
Phagocytosis, specifically the oxidative burst mechanism used to kill ingested pathogens, is impaired.
A patient experiences a sudden allergic reaction after exposure to peanuts. Which innate immune cell is most likely responsible?
Mast cells, which degranulate and release histamine upon allergen exposure.
Phagocytosis:
The process by which immune cells engulf and digest pathogens.
Opsonization:
The marking of pathogens for easier recognition and phagocytosis by immune cells.
Cytokines:
Signaling proteins that modulate immune responses.
Pattern Recognition Receptors (PRRs):
Receptors that recognize common microbial structures (PAMPs).
Membrane Attack Complex (MAC):
A structure formed by the complement system that creates pores in pathogen membranes, leading to cell lysis.
