Phagocytosis is the name of the process by which a white blood cell engulfs and destroys a microorganism such as a bacterium. The white blood cells that carry out phagocytosis are collectively known as phagocytes, and they include macrophages, neutrophils and dendritic cells.Know More
When a phagocyte encounters a bacterium in the body, the immune cell first sends out projections to surround and capture the invading organism. The white blood cell creates a vesicle around the bacterium and pulls it into the cell. Small vesicles filled with lysozymes merge with the vesicle holding the captured bacterium and the lysozymes then break down and destroy the microorganism. Most of the leftover bacterial particles are consumed by the cell, but some phagocytes send bacterial antigens to the cell surface to serve as signals so that other immune cells can learn which bacterial invaders the phagocyte has encountered. While they are engulfing and consuming an invading microorganism, phagocytes also release signal molecules to help coordinate the overall immune response.
Not all white blood cells perform phagocytosis. Some spray bacteria-destroying chemicals directly onto invading organisms instead of engulfing them first. Others release compounds that cause inflammation, which draws other immune cells to the area. The B-cells initially perform phagocytosis to identify pathogens, but once the invader is identified, B-cells shift to building and releasing antibodies instead.Learn more about Cells
White blood cells emerge from the bloodstream through capillaries and engage harmful molecules by either engulfing them or poisoning them. There are different types of white blood cells, which divide between them various infection-fighting activities, from detection to elimination.Full Answer >
Cellular diffusion is the process that causes molecules to move in and out of a cell. Molecules move from an area of high concentration to an area of low concentration. When there is a higher concentration of molecules outside of a cell, then more molecules enter the cell than leave. When there is a higher concentration of molecules inside of a cell, then more molecules leave the cell than enter.Full Answer >
Cell differentiation describes the process by which a cell is destined to become a particular type of cell, according to the Department of Biology at Kenyon College. The zygote is a cell formed from the union of sperm and an egg and is considered totipotent, meaning it can develop into any type of cell in the body. The first few cell divisions from this zygote are also totipotent.Full Answer >
Damaged human brain cells do not regenerate because the process that creates brain cells, neurogenesis, ceases before birth for many brain structures and in all but one brain structure by age two, according to BrainFacts.org. Brain cells only regenerate in the hippocampus.Full Answer >