Cellular Adoption

1. Cellular Adoption &
Tissue Response
Chapter # 10
Abasyn University Peshawar
Campus

2.  Cellular adaptation is the ability of cells to respond to various types
of stimuli and adverse environmental changes.
 Cellular adoption is, Reversible changes of cells in,
Size, number, phenotype,
metabolic activity and function
 To give in response to change in their environment
Cellular Adoption

3.  These adaptations include;
Hypertrophy (enlargement of individual cells),
Hyperplasia (increase in cell number),
Atrophy (reduction in size and cell number),
Metaplasia (transformation from one type of epithelium to another), and
Dysplasia (disordered growth of cells).
 Cells must constantly adapt, even under normal conditions, to
changes in their environment.
Cellular Adoption

4.  Hypertrophy (enlargement of individual cells)
 It’s the increase in the size of cells lead to caused increased in size of organ .
 No new cells generation, just increased the size of the cells.
 Synthesis of more structural components.
 Due to increased demand or stimulation by hormones & growth factors.
 Example, as in the enlargement of the breast and induction of lactation by
pregnancy.
1. Hypertrophy

5.  Causes of Hypertrophy
• Could be Physiologic and
pathologic
 Enlargement of uterus
pregnancy, action of estrogenic
hormones.
 Hypertrophy of heart the most
common stimulus is chronic
hemodynamic overload
1. Hypertrophy
Hypertrophy
Physiologic Pathologic
Hypertrophy of cardiac muscle,
Hypertrophy of smooth muscle,
Pregnancy

6. Hyperplasia (increase in cell number)
 It’s the increasing of cells numbers, lead to caused increased in
size of tissue / organ .
 Generation of new cells, and increased the size of the cells.
 Synthesis of more structural components.
2. Hyperplasia

7. Causes of Hyperplasia
• Could be Physiologic and pathologic
Physiologic hyperplasia: Occurs due to a normal
stressor.
For example, increase in the size of the breasts during
pregnancy
Increase in thickness of endometrium during menstrual
cycle
and liver growth after partial resection.
Pathologic hyperplasia: Occurs due to an abnormal
stressor.
2. Hyperplasia

8. Atrophy (reduction in size and cell number)
 Shrinking in size of the cell by the loss of cell substance is known
as Atrophy
 Atrophy (Reduced size of an organ or tissue, resulting from a
decrease in cell size and number)
 Atrophy is the progressive degeneration or shrinkage of muscle or
nerve tissue.
 Mostly occurred in fetus in infants
3. Atrophy

9. • Nutritional (starvation) atrophy
• Caused by starvation or
malnutrition
• Seen in proteins calorie
malnutrition (marasmus), due to
utilization of muscle protein as
an energy source.
3. Atrophy

10. • Loss of endocrinal stimulation
• After menopause: Loss of estrogen stimulation
• Menopause is the time that marks the end of menstrual cycles.
• Physiological atrophy of endometrium, (female reproductive part)
epithelium and breast.
3. Atrophy

11. Brain atrophy
Senile atrophy due to progressive developing atherosclerosis

12.  Metaplasia (transformation from one type of epithelium to another)
 Metaplasia is the replacement of one differentiated somatic cell type
with another differentiated somatic cell type in the same tissue.
 Metaplasia is a process whereby one type of mature tissue is
replaced by another type of mature tissue not indigenous to that
organ or tissue.
 Example; Squamous metaplasia
4. Metaplasia

13.  A term used to describe the presence of abnormal cells within a tissue
or organ.
 Dysplasia is not cancer, but it may sometimes become cancer.
 Dysplasia can be mild, moderate, or severe, depending on how abnormal
the cells look under a microscope and how much of the tissue or organ is
affected.
5. Dysplasia

14. Thank You
20
h
December,
2021