1. What is Phagocytosis?

    What are the 7 Steps of phagocytosis?
    Engulfing and destruction of invaders. it rids the body of debris after tissue injury.

    • 7 Steps:
    • Exposure/invasion
    • Attraction
    • Adherence
    • Recognition
    • Cellular ingestion
    • Phagosome formation
    • Degradation
  2. What triggers phagocytosis?
    Phagocytosis is triggered by injury or invasion or exposure, the first step of phagocytosis.
  3. What is Attraction?

    What are Chemotaxins?
    WBC Comes in contact with target ( antigen, invader or foreign protein).

    Chemotaxins: substances that attract neutrophils and macrophages. They come from damaged tissues and blood vessels.
  4. Adherence:

    What are Opsinins? What are its roles? How does it work?
    phagocytic cell must bind to target.

    Opsonins - increase contact by coating the target cell. ex. dead neutrophils, antibodies and activated (fixated) complement components. The process is called complement activation and fixation as part of the opsonization.

    Inactive complement proteins in the blood are stimulated and becomes active. it joins other activated complement proteins, surrounds an antigen and sticks to the antigen.
  5. Recognition
    The leukocytes checks the HLAs to see if it is a self or non self cell.
  6. Cellular ingestion
    The target cell is engulfed inside and form a vacuole.
  7. Phagosome Formation
    Occurs when the phagocyte's granules are inside the vacuole. These granules break and release enzymes that attack the ingested target.
  8. Degradation
    Enzymes inside the phagosome digest the target. It breaks into small particles.
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