plasma_protein_system_flashcards
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What are the three plasma protein systems involved in inflammation?
The complement, clotting, and kinin systems.
What are the primary functions of the complement system?
The complement system enhances inflammation, aids in phagocytosis (opsonization), and forms the membrane attack complex (MAC).
How is the complement system activated?
The complement system can be activated via the classical pathway, lectin pathway, or alternative pathway.
What is the role of C3 in the complement system?
C3 is a central component of the complement system, and its activation produces C3a and C3b, which drive inflammatory responses.
What is the function of C3a in inflammation?
C3a is an anaphylatoxin that induces mast cell degranulation, releasing histamine and promoting inflammation.
What is the function of C3b in the immune response?
C3b acts as an opsonin, binding to pathogens and enhancing their phagocytosis, and activates the next step in the complement cascade.
What is the role of C5a in inflammation?
C5a is a potent anaphylatoxin and a chemotactic factor that attracts neutrophils to sites of inflammation.
What is the membrane attack complex (MAC) and how does it function?
The membrane attack complex (C5b-C9) forms pores in bacterial membranes, leading to cell lysis and death.
How is the clotting system activated?
The clotting system is activated by the tissue factor (extrinsic) pathway or contact activation (intrinsic) pathway.
What is the role of thrombin in the clotting system?
Thrombin converts fibrinogen to fibrin, leading to clot formation, and produces small fibrinopeptides (FPs) that are pro-inflammatory.
What are fibrinopeptides (FPs) and their role in inflammation?
Fibrinopeptides (FPs) increase vascular permeability and act as chemotactic agents, attracting immune cells to the site of injury.
How does the clotting system contribute to inflammation?
The clotting system contributes to inflammation by forming a physical barrier (clot) and releasing inflammatory mediators like FPs.
What is the kinin system and what does it activate?
The kinin system activates bradykinin, which functions similarly to histamine in promoting inflammation.
What is the function of bradykinin in inflammation?
Bradykinin increases vascular permeability, stimulates pain receptors, and causes vasodilation.
How does the kinin system interact with the clotting system?
Factor XIIa from the clotting system activates kallikrein, which in turn activates bradykinin in the kinin system.
What triggers the activation of kallikrein in the kinin system?
Kallikrein is activated by Factor XIIa in the clotting system and helps convert prekallikrein to kininogen.
What is the role of factor XIIa in inflammation?
Factor XIIa plays a central role in both the clotting and kinin systems, linking them in the inflammatory response.
How do the plasma protein systems work together to promote inflammation?
The complement, clotting, and kinin systems interact to amplify inflammation by increasing vascular permeability and recruiting immune cells.
How do the complement system and kinin system affect vascular permeability?
Both the complement system (via C3a, C5a) and the kinin system (via bradykinin) increase vascular permeability during inflammation.
What is the chemotactic role of complement fragments like C5a in inflammation?
Complement fragments like C5a serve as chemotactic factors that guide neutrophils to the site of inflammation.
