Phagocytosis is sometimes described as 'cell eating' but it is not really a process by which the cell obtains nourishment. White blood cells called neutrophils and other cells of the immune system carry out phagocytosis to keep the body clear of unwanted bacteria and parasites.
When the phagocytic white cell detects bacteria, it moves its cytoplasm and cell wall towards the bacteria, in a sort of creeping motion. The extensions of the cell that form during this movement are called pseudopodia ~ false feet.
The cell membrane of the white cell completely surrounds a bacterium, enclosing it in a self contained vesicle called a phagosome. This vesicle is inside the white cell but the bacteria is a prisoner, surrounded by an internal cell wall to keep it away from the cell's cytoplasm.
The cell then moves lysosomes, vesicles full of digestive enzymes, towards the phagosome and these discharge into the inside of the bacterium's vesicle, where they kill it and degrade it. The cell then spits the bits out ~ the debris is moved towards the cell membrane and the membrane of the vesicle fuses with the cell membrane, pushing the debris out of the cell.
When the phagocytic white cell detects bacteria, it moves its cytoplasm and cell wall towards the bacteria, in a sort of creeping motion. The extensions of the cell that form during this movement are called pseudopodia ~ false feet.
The cell membrane of the white cell completely surrounds a bacterium, enclosing it in a self contained vesicle called a phagosome. This vesicle is inside the white cell but the bacteria is a prisoner, surrounded by an internal cell wall to keep it away from the cell's cytoplasm.
The cell then moves lysosomes, vesicles full of digestive enzymes, towards the phagosome and these discharge into the inside of the bacterium's vesicle, where they kill it and degrade it. The cell then spits the bits out ~ the debris is moved towards the cell membrane and the membrane of the vesicle fuses with the cell membrane, pushing the debris out of the cell.
