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The first demonstration of phagocytosis as a property of leucocytes, the immune cells, was from the German zoologist Ernst Haeckel. [5] [6] Haeckel discovered that blood cells of sea slug, Tethys, could ingest Indian ink (or indigo [7]) particles. It was the first direct evidence of phagocytosis by immune cells.
This material is then displayed to other cells of the immune system. Some phagocytes then travel to the body's lymph nodes and display the material to white blood cells called lymphocytes. This process is important in building immunity, [13] and many pathogens have evolved methods to evade attacks by phagocytes. [14]
Macrophages (/ ˈ m æ k r oʊ f eɪ dʒ /; abbreviated Mφ, MΦ or MP) are a type of white blood cell of the innate immune system that engulf and digest pathogens, such as cancer cells, microbes, cellular debris and foreign substances, which do not have proteins that are specific to healthy body cells on their surface.
An excess of white blood cells is usually due to infection or inflammation. Less commonly, a high white blood cell count could indicate certain blood cancers or bone marrow disorders. The number of leukocytes in the blood is often an indicator of disease, and thus the white blood cell count is an important subset of the complete blood count.
Macrophages, neutrophils, and dendritic cells are all cells of the innate immune system that utilize phagocytosis and are equipped with Toll-like receptors (TLR). Toll-like receptors are present on each of these cells and recognize a variety of microbial products resulting in the induction of more specific immune responses. [ 2 ]
This is a list of immune cells, also known as white blood cells, white cells, leukocytes, or leucocytes. They are cells involved in protecting the body against both infectious disease and foreign invaders .
The first demonstration of phagocytosis as a property of leukocytes, the immune cells, was from the German zoologist Ernst Haeckel. [14] [15] In 1846, English physician Thomas Wharton Jones had discovered that a group of leucocytes, which he called "granule-cell" (later renamed and identified as eosinophil [16]), could change shape, the phenomenon later called amoeboid movement.
Neutrophils are the most abundant white blood cells in the human body (approximately 10 11 are produced daily); they account for approximately 50–70% of all white blood cells (leukocytes). The stated normal range for human blood counts varies between laboratories, but a neutrophil count of 2.5–7.5 × 10 9 /L is a standard normal range.