The document discusses necrosis and apoptosis, defining both processes and outlining their differences. It details the six types of necrosis, including coagulative, liquefactive, caseous, fat, gangrenous, and fibrinoid, with examples and characteristics of each. The document also describes morphological changes associated with necrosis and the implications of cell death on tissues and organs.

1. Necrosis
By- Sheril S. Philip
15BCB0120

2. • Define necrosis and apoptosis
• List the different types of necrosis, examples
of each and its features
• List the different conditions associated with
apoptosis, its morphology and its mechanism
• Know the difference between apoptosis and
necrosis
CONTENTS

3. Define necrosis and apoptosis
 List the different types of necrosis, examples
of each and its features
 List the different conditions associated with
apoptosis, its morphology and its mechanism
 Know the difference between apoptosis and
necrosis

4. Cell Death
Death of cells occurs in two ways:
1. Necrosis--(irreversible injury) changes produced by
enzymatic digestion of dead cellular elements
2. Apoptosis--vital process that helps eliminate unwanted
cells--an internally programmed series of events
effected by dedicated gene products

5. Morphology of necrosis :
1. Cellular swelling or rupture
2. Denaturation and coagulation of
cytoplasmic proteins
3. Breakdown of cell organelles
4. Breakdown of nuclear DNA

6. Patterns of Necrosis In Tissues or Organs
As a result of cell death the tissues or organs display
one of these six macroscopic changes:
1. Coagulative necrosis
2. Liquifactive necrosis
3. Caseous necrosis
4. Fat necrosis
5. Gangrenous necrosis
6. Fibrinoid necrosis

7. Patterns of Necrosis In Tissues or Organs
1. Coagulative necrosis:
the outline of the dead cells are maintained
and the tissue is somewhat firm.
Example: myocardial infarction
1. Liquefactive necrosis:
the dead cells undergo disintegration and
affected tissue is liquefied.
Example: cerebral infarction.

8. Patterns of Necrosis In Tissues or Organs
3. Caseous necrosis:
a form of coagulative necrosis (cheese-like).
Example: tuberculosis lesions.
4. Fat necrosis:
enzymatic digestion of fat.
Example: necrosis of fat by pancreatic enzymes.
5. Gangrenous necrosis:
Necrosis (secondary to ischemia) usually with superimposed
infection.
Example: necrosis of distal limbs, usually foot and toes in diabetes.
6. Fibrinoid necrosis: typically seen in vasculitis
and glomerular autoimmune diseases

9. Coagulative Necrosis
Changes in the cytoplasm
and the nucleus
Karyolysis Pyknosis
Karyorrhexis

10. Necrosis of the liver induced by herpesvirus.
Herpesvirus invades liver cell nuclei producing nuclear ('ground
glass') mildly basophilic inclusions.

11. Acute renal tubular necrosis (ischemia) :
increased eosinophilia and pyknosis in necrotic cells
Normal
Necrotic

12. Ischemic neuronal injury:acidophilic cytoplasm & nuclear pyknosis

13. … a mess - so many
cells have died - the
tissue is not
recognizable. Nuclei
have become pyknotic
(shrunken and dark),
undergone karorrhexis
(fragmentation) and
karyolysis(dissolution)
Necrotic myocardium

14. Kidney: ischemia and infarction
(loss of blood supply and resultant
tissue anoxia).
Coagulative necrosis
Removal of
the dead
tissue
leaves
behind a
scar

15. Infarcts (vascular distribution) are wedge-shaped
with a base on the organ capsule.
Coagulative necrosis: is due to loss of blood supply
Spleen

16. Depending on circumstances:
1. necrotic tissue may be walled off by scar tissue,
2. totally converted to scar tissue,
3. get destroyed (producing a cavity or cyst),
4. get infected (producing an abscess or "wet gangrene"),
5. or calcify.
If the supporting tissue framework does not die, and the dead
cells are of a type capable of regeneration, you may have
complete healing.
Remember: True coagulation necrosis involves groups of cells, and is
almost always accompanied, by acute inflammation (infiltrate)