This presentation deals with cell injury

1. CELL INJURY
AND
CELLULAR
ADAPATION
Dr Akshay Shetty
Associate Professor
SSRAMCH Inchal

2. Contents
30/04/2024 CELL INJURY AND CELL ADAPTION (Dr Akshay Shetty) 2
Objectives
Definition of Cell Injury
Causes of Cell injury
Reversible and Irreversible Cell Injury
Cellular adaptation
Cellular death
Summary
References

3. Objectives
By the end of the presentation the students
must be able to
1. Define Cell Injury
2. List Causes of Cell injury
3. Discuss Reversible and Irreversible Cell
Injury
4. Define Cellular adaptation
5. Illustrate types and mechanism of Cellular
adaptation
6. Describe Cellular death
30/04/2024 CELL INJURY AND CELL ADAPTION (Dr Akshay Shetty) 3

4. Cell injury
30/04/2024 CELL INJURY AND CELL ADAPTION (Dr Akshay Shetty) 4
Cell injury is defined as the
cellular changes caused by
stress which exceed the cell’s
adaptive capability .
cell injury results when cells are
stressed so severely that they
are no longer able to adapt, or
when cells are exposed to
inherently damaging agents, or
suffer from intrinsic
abnormalities

5. 4/30/2024 CELL INJURY AND CELL ADAPTION (Dr Akshay Shetty) 5
Cell injury
Reversible
Irreversible

6. Reversible
In early stages or mild forms of injury
the functional and morphologic
changes are reversible, if the
damaging stimulus is removed.
• At this stage, although there may be
significant structural and functional
abnormalities, the injury has
typically not progressed to severe
membrane damage and nuclear
dissolution
30/04/2024 CELL INJURY AND CELL ADAPTION (Dr Akshay Shetty) 6

7. Earliest changes associated with cell injury are :
Decreased generation of ATP.
Loss of cell membrane integrity.
Defects in protein synthesis.
Cytoskeletal damage.
DNA damage
30/04/2024 CELL INJURY AND CELL ADAPTION (Dr Akshay Shetty) 7

8. Irreversible injury is marked by :
Severe mitochondrial vacuolization.
Extensive damage to plasma
membranes.
Swelling of lysosomes.
The appearance large, amorphous
densities in mitochondria
30/04/2024 CELL INJURY AND CELL ADAPTION (Dr Akshay Shetty) 8

9. 30/04/2024 CELL INJURY AND CELL ADAPTION (Dr Akshay Shetty) 9

10. Causes of Cell injury
• Oxygen deprivation
• Chemical agents
• Physical agents
• Infectious agents
• Immunologic reactions
• Nutritional imbalances
• Genetic factors
• Aging
30/04/2024 CELL INJURY AND CELL ADAPTION (Dr Akshay Shetty) 10

11. 30/04/2024 CELL INJURY AND CELL ADAPTION (Dr Akshay Shetty) 11

12. Cell Adaption
When a cell undergoes physiological
stresses or pathological affect, it
encounters the stress by undergoing
adaption , it achieves a new steady state
preserving viability and function.
30/04/2024 CELL INJURY AND CELL ADAPTION (Dr Akshay Shetty) 12

13. Hyperplasia: It is an increase
in the number of cells
Cause: hyperplasia is usually
a response to growth factors
(i.e. hormones).
Note: Hyperplasia can be
physiologic or pathologic.
Clinical application :
A. Endometrial hyperplasia
induced by estrogen.
B. Endocrine stimulation,
e.g. Thyroid.
C. Focal nodular hyperplasia
(liver).
D. The response of foot cells
to uncomfortable shoes.
30/04/2024 CELL INJURY AND CELL ADAPTION (Dr Akshay Shetty) 13

14. Hypertrophy : It is an increase in the
size of cells resulting an increase in
organ size( occurs in tissues incapable
of cell division I,e muscle tissue )
Note: Hypertrophy can be physiologic
or pathologic
# Clinical applications:
Hypertrophy of the uterus during
pregnancy
Hypertrophy of cardiac muscle,
typically myocardial tissue
30/04/2024 CELL INJURY AND CELL ADAPTION (Dr Akshay Shetty) 14

15. Atrophy : Shrinkage in the
size of the cell by the loss
of cell substance
A. Atrophy of the brain in
Alzheimer disease
B. Thinning of the bones in
Osteoporosis
30/04/2024 CELL INJURY AND CELL ADAPTION (Dr Akshay Shetty) 15

16. Metaplasia : a
change in which an
adult cell type is
replaced by
another type.
The cell is replaced by
another cell more
capable to withstand
the adverse
environment
Bronchial mucosa
replaced by
squamous
epithelium
(smoking).
Cervical columnar
epithelium replaced
by squamous
epithelium
(cervicitis)
30/04/2024 CELL INJURY AND CELL ADAPTION (Dr Akshay Shetty) 16

17. Cell death
When the injury becomes irreversible, at that time the cell cannot
recover , thus it dies, this is called (cell death)
Apoptosis Necrosis
30/04/2024 CELL INJURY AND CELL ADAPTION (Dr Akshay Shetty) 17

18. Apoptosis
Apoptosis is programmed cell
death (single cell death) which
is commanded by genes inside
the cell, and it happens due to
physiologic or pathologic
events.
30/04/2024 CELL INJURY AND CELL ADAPTION (Dr Akshay Shetty) 18

19. Examples of Physiologic (normal) apoptosis include the:
• Programmed death of embryonic cells (in the embryonic life) in the limb buds
leading to the formation of fingers and toes (this is useful)
• Hormone-induced cell death of endometrial cells at the end of the menstrual
cycle.
• During lactation in the female, the breast becomes big and the glands become
hyperplastic and big and they produce milk. To stop lactation it has to undergo
apoptosis therefore the breast shrink (becomes small) and the glands disappear.
• To eliminate immune cells after cytokine depletion and auto reactive T cells in
developing thymus.
30/04/2024 CELL INJURY AND CELL ADAPTION (Dr Akshay Shetty) 19

20. Examples Pathologic apoptosis include:
• Hepatitis virus-induced liver cell apoptosis (acidophilic
bodies)
• Immune injury-related skin kerationcytes (civatte
bodies)
• Corticosteroid-induced atrophy of the neonatal
thymus.
30/04/2024 CELL INJURY AND CELL ADAPTION (Dr Akshay Shetty) 20

21. Necrosis: is a morphologic sign of cell death in a living tissue.
Types of necrosis:
• Coagulative necrosis is caused by hypoxemia and ischemia and it causes myocardial
infarction (coagulative necrosis affects mainly the heart, the lung, the spleen and the
kidneys)
Character : Cells' shape is maintained even after it's death.
• Liquefactive necrosis has two good examples (brain and abscess) and it caused by hypoxia
to the brain.
Character: part of the tissue appear as liquid (no cells)
30/04/2024 CELL INJURY AND CELL ADAPTION (Dr Akshay Shetty) 21

22. Caseous necrosis is typically seen in tuberculosis (happens mainly in the lung or
the lymph node) Histologically, it consists of granular material surrounded by
epithelioid and multinucleated giant cells.
Character: the tissue appears cheesy
• Fibrinoid necrosis is seen usually in the kidney and the blood vessels. It is immunologically mediated and
seen in autoimmune diseases. Blood vessels are impregnated by fibrin and other serum proteins and
appear magenta-red in histologic sections.
Character: Blood vessels are impregnated by fibrin
30/04/2024 CELL INJURY AND CELL ADAPTION (Dr Akshay Shetty) 22

23. Fat necrosis happens in the organs which are rich in fat. In case of acute
pancreatitis, the enzymes (lipolytic enzymes like amylase and lipase) in the
necrotic pancreatic cells are released to the abdominal cavity and start to digest
the fat. Free fatty acid released from fat cells bind with calcium to form white
specks or streaks composed of calcium soaps.
Character: white specks or streaks composed of calcium soaps
30/04/2024 CELL INJURY AND CELL ADAPTION (Dr Akshay Shetty) 23

24. Summary
30/04/2024 CELL INJURY AND CELL ADAPTION (Dr Akshay Shetty) 24
1.Define Cell
Injury
01
List Causes of
Cell injury
02
Discuss
Reversible and
Irreversible Cell
Injury
03
Define Cellular
adaptation
04
Illustrate types
and mechanism
of Cellular
adaptation
05
Describe
Cellular death
06

25. References
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7171462/
• https://ksumsc.com/download_center/Archive/1st/432/01%20FOUNDATION
%20BLOCK/432%20Teams%20Work/Pathology/Cell%20adaption%20%26%2
0Cell%20Injury.pdf
30/04/2024 CELL INJURY AND CELL ADAPTION (Dr Akshay Shetty) 25

26. THANK YOU
30/04/2024 CELL INJURY AND CELL ADAPTION (Dr Akshay Shetty) 26