Cell injury: CELL ADAPTATIONS

cell adaptations

1. CELLULAR ADAPTATIONS
AND
INJURY
Dr Vijay Shankar S

3. •Introduction
•Cellular adaptations
•Types of adaptations
•Mechanism
•Examples

4. Pretest
1.In smokers ,the ciliated columnar
epithelium of trachea and bronchi are
replaced by squamous epithelium. This is
an example of
A. Hyperplasia
B. Dysplasia
C. Metaplasia
D. Hypertrophy

5. •2. Skin ‘warts’ is an example for
A. Hyperplasia
B. Dysplasia
C. Metaplasia
D. Hypertrophy

7. NORMAL CELL
(HOMEOSTASIS)
STRESS
ADAPTATION CELL INJURY
INABILITY
TO
ADAPT
REVERSIBLE INJURY
MILD
TRANSIENT
SEVERE
PROGRESSIVE
IRREVERSIBLE INJURY
NECROSIS APOPTOSIS
CELL
DEATH

8. CELLULAR ADAPTATIONS
ATROPHY
HYPERTROPHY
HYPERPLASIA
METAPLASIA
•New , steady altered
state
• Allows them to survive
•Continue to function
•In abnormal
environment

9. ATROPHY
•Decrease in the number and size of the
cells of an organ
•Mechanism :Decreased protein synthesis and
increased protein degradation in
the cells

10. ATROPHY
PHYSIOLOGIC
ATROPHY
PATHOLOGIC
ATROPHY
1.Disuse atrophy
2.Nutritional/starvation
atrophy
3.Ischemic atrophy
4.Neuropathic
5.Loss of endocrine
stimulation
6.Pressure atrophy
1.Decrease in size of
uterus after
parturition
2.Brain, with ageing

15. HYPERTROPHY
•Increase in the SIZE of the parenchymal
cells in the organ
•Cause :
•Increased functional demand or
•By stimulation of hormones and growth factors

16. •Mechanisms :
•Increased production of cellular proteins.

17. HYPERTROPHY
PHYSIOLOGIC
HYPERTROPHY
PATHOLOGIC
HYPERTROPHY
1.Skeletal muscle
2.Cardiac muscle
3.Smooth muscle
4.Compensatory
hypertrophy
1. Enlarged size of
the uterus in
pregnancy

25. HYPERPLASIA
•Increase in the NUMBER of cells in an
organ
•It takes place if the cell population is
capable of dividing
•Mechanism :
•Results from growth factor induced proliferation of
mature cells or
•Increased output of new cells from stem cells.

26. HYPERPLASIA
PHYSIOLOGIC
HYPERPLASIA
PATHOLOGIC
HYPERPLASIA
1.Hormonal excess-
endometrial, prostate
2.Certain viral
infections:papillomavirus
- warts
1. Enlarged size of
the uterus in
pregnancy
2.Breast – puberty
pregnancy,
lactation
Compensatory
hyperplasia
Regeneration of
liver, kidney and
skin
Marrow hyperplasia

31. METAPLASIA
•It is a reversible change in which one
differentiated cell type (epithelial or
mesenchymal) is replaced by another cell
type

32. Mechanism
•Due to REPROGRAMMING of the
precursor cells, present in the normal
tissues.

33. METAPLASIA
EPITHELIAL
METAPLASIA
MESENCHYMAL
METAPLASIA
1.OSSEOUS METAPLASIA
1.Arterial wall
2.Myositis ossificans
3.Stroma of tumor
4.Cartilage of larynx in
elderly
2.CARTILAGENOUS
METAPLASIA
1.Healing of fractures
1. SQUAMOUS
METAPLASIA
1.Bronchus
2.Uterine cervix
3.Gall bladder
4.Renal pelvis
2.COLUMNAR
METAPLASIA
1.Barrett’s
esophagus
2.Healed gastric
ulcer

38. Post test
1.In smokers ,the ciliated columnar
epithelium of trachea and bronchi are
replaced by squamous epithelium.
This is an example of
A. Hyperplasia
B. Dysplasia
C. Metaplasia
D. Hypertrophy

C

39. •2. Skin ‘warts’ is an example for
A. Hyperplasia
B. Dysplasia
C. Metaplasia
D. Hypertrophy
A