NUR 229 Lecture Notes - Lecture 33: Hormone Therapy, Sickle-Cell Disease, Lymphokine
Document Summary
The cell cycle is a sequence of growth stages that a cell moves through for mitosis and regeneration. In order for cells to undergo mitosis, the cell must go through stages g0, g1, s, g2 and m. Cancer cells are constantly moving through the cell cycle stages. During the cell cycle, there are several checkpoints where dna replication mechanisms can be stopped if errors have occurred in the synthesis of cell parts before mitosis. Cells can undergo repair, recycling, or apoptosis if errors exist. Cancer cells do not undergo scrutiny at these checkpoints and do not undergo apoptosis (programmed degeneration). Cancer cells disregard the growth inhibitors released by neighboring cells. As the cancer cells proliferate, they accumulate on top, around, and beside each other, take over boundaries of organs, crowd out normal cells, cross basement membranes and may even break free and travel to distant body sites. Our immune system constantly surveys the body for foreign substances or non-self antigens.
