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Section 3
Apoptosis
Definition: This term has been used for a
mechanism of cell death affecting single cells
scattered in a population of healthy cells. It
differs from necrosis and represents a
physiological process by which effete and
abnormal cells die and are eliminated.
Mechanism: gene determined single cell
death. Programmed cell death.
Process:

The dying process: active metabolic changes
in the cell cause cytoplasm and nuclear
condensation→
cell
disintegrates
into
apoptotic bodies each surrounded by a
plasma membrane.

The elimination process: phagocytosis by
surrounding cells followed by rapid digestion.
The presence of intact plasma membranes
around the apoptotic bodies explains the
absence of inflammation.
（From ROBBINS BASIC PATHOLOGY，2003）
（From ROBBINS BASIC PATHOLOGY，2003）
（From ROBBINS BASIC PATHOLOGY，2003）
A,Apoptosis in the skin in an immune-mediated reaction B,High
power of apoptotic cell in live in immune-mediated hepatic cell
injury. （From ROBBINS BASIC PATHOLOGY，2003）
Agarose gel electrophoresis of DNA
Lane A: Control
Lane B: extensive apoptosis. Ladder patter
Lane C: massive necrosis
（From ROBBINS BASIC PATHOLOGY，
2003）
Significance:



Apoptosis is important physiologically in
balancing cell proliferation and elimination. It is
associated with:
maintenance of the organ size in the adult.
organ development and modeling in the embryo.
physiological atrophy and involution.
It is also important in pathological processes
particularly associated with organ atrophy and
cell elimination (e. g. in tumor growth and
leukaemia).