In 1884, Elie Metchnikoff observed cells collected around a splinter inserted in a sea star embryo. This was the discovery of
a. blood cells.
b. sea stars.
c. phagocytosis.
d. immunity.
e. none of the above

Verified step by step guidance

1. Identify the context of the observation: Elie Metchnikoff's work in 1884.
2. Understand the significance of cells collecting around a foreign object, such as a splinter.
3. Recognize that this process involves cells engulfing and digesting foreign particles.
4. Connect this process to the concept of phagocytosis, where cells ingest harmful particles or pathogens.
5. Conclude that Metchnikoff's observation led to the discovery of phagocytosis.

Key Concepts

Phagocytosis

Phagocytosis is a cellular process in which certain cells, known as phagocytes, engulf and digest foreign particles, bacteria, or dead cells. This mechanism is crucial for the immune response, as it helps eliminate pathogens and debris from the body. Elie Metchnikoff's observations in sea star embryos highlighted the role of these cells in innate immunity, marking a significant advancement in our understanding of how organisms defend themselves against infections.

Innate Immunity

Innate immunity is the first line of defense in the immune system, providing immediate but non-specific protection against pathogens. It includes physical barriers like skin, as well as immune cells such as phagocytes that respond quickly to infections. Metchnikoff's work contributed to the understanding of innate immunity by demonstrating how organisms utilize phagocytosis to combat invading microorganisms.

Elie Metchnikoff

Elie Metchnikoff was a Russian zoologist and immunologist who is best known for his pioneering work in the field of immunology, particularly for discovering phagocytosis. His research in the late 19th century laid the foundation for understanding how immune cells protect the body from infections. Metchnikoff's observations of immune responses in invertebrates, such as sea stars, were instrumental in shaping modern immunological concepts.