General pathology

1. Prof.Dr.
Khalil Hassan Zenad
Aljeboori
Copyrights©2017lAliraqiaUniversitylDentistrylPathologylProf.Dr.KhalilHassanZenadAljeboori.
NECROSIS AND APOPTOSIS
(IRREVERSIBLE CELL INJURY)
Lecture 3

2. Copyrights©2017lAliraqiaUniversitylDentistrylPathologylProf.Dr.KhalilHassanZenadAljeboori.
Apoptosis:
It is programmed cell death in which the relevant cell activate enzyme capable to degrading
the cell own nuclear DNA and other cytoplasmic and nuclear proteins, the apoptic cell (dead)
is rapidly cleared before its content have leaked out and therefore the cell death by this path
way does not elicit inflammatory reaction in the host .
Causes of apoptosis:
It is physiological in nature so it is important in physiological conditions :
1.During embryogenesis (organogenesis and involution) .
2.Involution of hormone dependent tissue example damage of endometrium during
menstrual cycle and regression of lactating breast .
3.In proliferating cells ( intestinal epithelium ) maintain aconstant number .
4.In the cell served their function like neutrophils in inflammation. 5.In self reactive
lymphocytes to prevent tissue destruction .
6. Cytotoxic T cells against viral infected cells or tumor cell .

3. Copyrights©2017lAliraqiaUniversitylDentistrylPathologylProf.Dr.KhalilHassanZenadAljeboori.
Microscopically:
Apoptic cell appear round or oval intense cytoplasm
eosinophilic condensed chromatin , fragmented
(karyorrhexis )shrinkage of cells with cytoplasmic buds
and fragment into apoptic bodies composed of membrane
bound vesicles of cytoplasm and organells?
, these fragment are phagocytosed without eliciting
inflammatory reaction .

4. Copyrights©2017lAliraqiaUniversitylDentistrylPathologylProf.Dr.KhalilHassanZenadAljeboori.
Necrosis :
Is a local death of tissue in the living body , the process
of degeneration that lead to death termed necrobiosis .
The apoptosis differ from necrosis that in :
Apoptosis Necrosis
1- no still intact . 1- loss of membrane integrity .
2- no leakage . 2- leakage of cell contents .
3- no inflammatory . 3- inflammatory host reaction .

5. Copyrights©2017lAliraqiaUniversitylDentistrylPathologylProf.Dr.KhalilHassanZenadAljeboori.
1.coagulative necrosis : Occur by cut blood supply(infarction) in Such
necrosis the general architecture of tissue are preserved and loss of cellular
details, firm in texture , pale.
Microscopically:
homogeneous cytoplasm,eosinophilic and nuclear changes,pyknosis,karyolysis and
karyorrhexis,coagulative necrosis or ischemic necrosis termed.the necrotic cell either removed
by leukocytes or digested by leukocytes lysosomal enzymes.
2.liquefactive necrosis:In which complete digestion of dead cells and
tissue leaving liquid mass enclosed within cystic cavity .
Liquefaction necrosis occur by two ways:
A.Focal pyogenic bacterial infection with pus production (abscess).
B.Ischemic destruction of brain tissue leaving a cavity filled with fluid,edema .
Types of necrosis:

6. Copyrights©2017lAliraqiaUniversitylDentistrylPathologylProf.Dr.KhalilHassanZenadAljeboori.
3.Caseous necrosis :Occur in tuberculosis with production cheesy like
material in the center of tubercles .
Microscopically :The caseation appear as amorphous granular mass,
complete loss of tissue structure and cellular details, the necrotic area
surrounded by inflammatory cellular reaction forming granuloma .
4. Fat necrosis : This occur in acute pancreatitis in which pancreatic lipase
lysis fat cells of pancreas and peritoneum, then the triglycerides split into
fatty acids combine with Ca++ → give violet colour,
with K+→ pink colour, with Na+ → blue colour .
Microscopically :
Grossly white chalky material, it occur also in female breast following
trauma ( traumatic fat necrosis), the dead fatty tissue become soapy material
like in the necrotic fatty area.
Types of necrosis:

7. Copyrights©2017lAliraqiaUniversitylDentistrylPathologylProf.Dr.KhalilHassanZenadAljeboori.
5. Gangrenous necrosis : It is not a distinctive pattern of cell death , the term still use clinically, it
occur in limbs , lower legs following cut blood supply , under going into coagulative necrosis
(dry gangrene )when infected by bacteria modify into liquefactive action of bacteria and attract
leukocytes become wet gangrene with gas bubbles production .
Moist gangrene Dry gangrene
1.In enriched blood supply organs lung and intestine. 1.In ill blood supply organs limb hands.
2.Not prominent inflammation zone. 2.Prominent inflammatory zone.
3. Putrefied odor more. 3.Less putrefied odor.
4. Too much gas bubbles. 4.Less gas bubbles.
6. Fibrinoid necrosis : Seen in the immune response involving blood vessels , deposition of immune
complexes with fibrin leakage from B.V. result in bright pink of amorphous material this type appear
in polyarteritisnodosa.
The leakage of proteins from dead cells result into for examples cardiac muscles fibers give
creatininekinase , troponine , liver cells give GOT,GPT and ALK phosphatase.
Types of necrosis:

8. Copyrights©2017lAliraqiaUniversitylDentistrylPathologylProf.Dr.KhalilHassanZenadAljeboori.
The Autolysis differ from necrosis that in :
NecrosisAutolysis
1. Presence of dead tissue
and living tissue.
1. All dead tissue.
2. Dead tissue accompanied
by inflammatory reaction.
2. Only dead tissue.
3. Congestion and RBCs
living.
3. All RBCs lysed.

9. Copyrights©2017lAliraqiaUniversitylDentistrylPathologylProf.Dr.KhalilHassanZenadAljeboori.
A. Liquefaction ,removed by blood , lymph .
B. Liquefaction ,cyst formation .
C. Liquefaction abscess formation .
D. Sloughing , desquamation .
E. Replacement by scar tissue .
F. Calcification.
G. Gangrene , necrosis invaded by saprophytic
bacteria(dry and moist gangrene) .
Fate of necrosis :

10. PRESENTATION ENDS
Copyrights © 2017 l Aliraqia University l Dentistry l Pathology l Prof.Dr. Khalil Hassan Zenad Aljeboori.
THANKS FOR LISTENING