Chapter - 4
morphology of irreversible cell injury
(cell death)
Introduction:
Cell death is a state of irreversible injury.
It may occur in the living body as a local change (i.e., autolysis,
necrosis, and apoptosis).
Local changes follow it (i.e., gangrene and pathologic calcification).
Finally, the result of somatic death or cell death.
Autolysis (Postmortem self-digestion):
Autolysis (i.e., self-
digestion) is a process in
which a cell disintegrates
by its own enzymes,
liberated by lysosomes.
Autolysis is rapid in
tissues like the
pancreas & gastric
mucosa (Rich in
hydrolytic enzymes).
Autolysis is intermediate in tissues like the heart, liver, and kidney.
Slow in fibrous tissue.
Necrosis:
It is defined as localized area death of tissue, due to degradation of
tissue by hydrolytic enzymes.
Pathological process of cell death in living tissue.
It is done by irreversible injury.
Basic mechanism is denaturation of proteins & enzymatic digestion
of dead cells.
Always an inflammatory response present.
1|Page @Shoaiba Chaudhary Medical Pathology Notes
, There are five types of necrosis:
1. Coagulative
2. Liquefaction
3. Caseous
4. Fat
5. Fibrinoid
Apoptosis (Programmed cell death):
It is a regulated process of programmed cell death.
It is essential for development, tissue homeostasis & defense
against disease.
Apoptosis is a Greek word that means ‘falling off’ or ‘dropping off’
The term was introduced in 1972.
Biological importance of apoptosis:
Embryonic development (e.g., digit formation)
Tissue homeostasis
2|Page @Shoaiba Chaudhary Medical Pathology Notes
morphology of irreversible cell injury
(cell death)
Introduction:
Cell death is a state of irreversible injury.
It may occur in the living body as a local change (i.e., autolysis,
necrosis, and apoptosis).
Local changes follow it (i.e., gangrene and pathologic calcification).
Finally, the result of somatic death or cell death.
Autolysis (Postmortem self-digestion):
Autolysis (i.e., self-
digestion) is a process in
which a cell disintegrates
by its own enzymes,
liberated by lysosomes.
Autolysis is rapid in
tissues like the
pancreas & gastric
mucosa (Rich in
hydrolytic enzymes).
Autolysis is intermediate in tissues like the heart, liver, and kidney.
Slow in fibrous tissue.
Necrosis:
It is defined as localized area death of tissue, due to degradation of
tissue by hydrolytic enzymes.
Pathological process of cell death in living tissue.
It is done by irreversible injury.
Basic mechanism is denaturation of proteins & enzymatic digestion
of dead cells.
Always an inflammatory response present.
1|Page @Shoaiba Chaudhary Medical Pathology Notes
, There are five types of necrosis:
1. Coagulative
2. Liquefaction
3. Caseous
4. Fat
5. Fibrinoid
Apoptosis (Programmed cell death):
It is a regulated process of programmed cell death.
It is essential for development, tissue homeostasis & defense
against disease.
Apoptosis is a Greek word that means ‘falling off’ or ‘dropping off’
The term was introduced in 1972.
Biological importance of apoptosis:
Embryonic development (e.g., digit formation)
Tissue homeostasis
2|Page @Shoaiba Chaudhary Medical Pathology Notes
