Pathology 2420A Lecture Notes - Lecture 2: Endoplasmic Reticulum, Phosphatidylserine, Cell Membrane
29 Nov 2017
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Document Summary
When cells are damaged by harmful factors (such as injury or toxic chemicals), they usually spill their guts as they die. Because the damaged cell"s plasma membrane can no longer control the passage of ions and water, the cell swells up, and its contents leak out through holes in the plasma membrane. This often causes inflammation in the tissue surrounding the dead cell. Cells that undergo apoptosis go through a different and much more orderly process. They shrink and develop bubble-like protrusions (technical name: The dna in the nucleus gets chopped up into small pieces, and some organelles of the cell, such as the endoplasmic reticulum, break down into fragments. In the end, the entire cell splits up into small chunks, each neatly enclosed in a package of membrane. They release signals that attract debris-eating (phagocytic) immune cells, such as macrophages. Also, the fragments of the dying cell display a lipid molecule called phosphatidylserine on their surface.
