Phagocytes are the white blood cells that protect the body by ingesting (phagocytosing) harmful foreign particles, bacteria and dead or dying cells. They are essential for fighting infections, and for subsequent immunity. Phagocytes are important throughout the animal kingdom, and are highly developed in vertebrates. One liter of human blood contains about six billion phagocytes. Phagocytes were first discovered in 1882 by Ilya Ilyich Mechnikov while he was studying starfish larvae. Phagocytes of humans and other animals are called professional or non-professional, depending on how effective they are at phagocytosis. The professional phagocytes include cells called neutrophils, monocytes, macrophages, dendritic cells, and mast cells. The main difference between professional and non-professional phagocytes is that the professional phagocytes have molecules called receptors on their surfaces that can detect harmful objects, such as bacteria, that are not normally found in the body. Phagocytes are therefore crucial in fighting infections, as well as in maintaining healthy tissues by removing dead and dying cells that have reached the end of their life-span. During an infection, chemical signals attract phagocytes to places where the pathogen has invaded the body.

Read the rest of this article: http://en.wikipedia.org/wiki/Phagocyte

_______________________________ Today's selected anniversaries:

1538:

Spainish Conquistador Gonzalo Jiménez de Quesada founded a European urban settlement in what is today Bogotá, Colombia. http://en.wikipedia.org/wiki/Bogot%C3%A1

1806:

The Holy Roman Empire was dissolved by its last emperor Francis II during the aftermath of the War of the Third Coalition. http://en.wikipedia.org/wiki/Francis_II%2C_Holy_Roman_Emperor

1945:

World War II: The U.S. Army Air Force bomber Enola Gay dropped an atomic bomb named Little Boy on Hiroshima, Japan, killing as many as 140,000 people. http://en.wikipedia.org/wiki/Enola_Gay

1991:

British computer programmer Tim Berners-Lee first posted files describing his ideas for a system of interlinked, hypertext documents accessible via the Internet, to be called a "World Wide Web". http://en.wikipedia.org/wiki/Tim_Berners-Lee

2008:

Mauritanian President Sidi Mohamed Ould Cheikh Abdallahi was ousted from power by a group of high ranking generals that he had dismissed from office several hours earlier. http://en.wikipedia.org/wiki/2008_Mauritanian_coup_d%27%C3%A9tat

_____________________________ Wiktionary's word of the day:

spackle (v): 1. To fill cracks or holes with a plastic paste. 2. To fill gaps with something; to speckle http://en.wiktionary.org/wiki/spackle

___________________________ Wikiquote quote of the day:

I hold it true, whate'er befall;

I feel it, when I sorrow most; 'Tis better to have loved and lost Than never to have loved at all. --Alfred Tennyson http://en.wikiquote.org/wiki/Alfred_Tennyson