This document discusses various types of cellular and tissue changes including hypertrophy, hyperplasia, atrophy, and metaplasia. It notes that hypertrophy involves an increase in size of cells rather than number, and can be physiological such as in pregnancy, or pathological. Hyperplasia is an increase in cell number due to cell replication. Atrophy is a shrinkage in cell size and organ size, and can also be physiological or pathological. Metaplasia is a reversible change where one adult cell type is replaced by another.

6.  Hypoxia
 Physical Agents
 Chemicals
 Infections
 Immunological Reactions
 Genetic Errors
 Nutritional Imbalances

7.  Hyperplasia
 Hypertrophy
 Atrophy
 Metaplasia

8.  Non dividing cells
 Physiological
 Pathological
 Cells not capable of replication
 Mechanisms
mechanical triggers
trophic triggers
Ex :hypertrophy of heart
uterus in pregnancy
Skeletal muscle in body builders

9.  Increased production of structural proteins
 Switch of contractile proteins from adult to
fetal
 Expression of fetal genes

11.  Cells capable of replication
 Increase in no of cells
 Increase in size of the organ
 Physiologic and pathologic

12.  Hormonal
 Compensatory
Mechanisms of hyperplasia
local production of growth factors
activation of intra cellular pathway
stem cells

13.  Excessive hormonal stimulation
 Bph , endometrial hyperplasia
 Fertile soil for cancerous proliferations

14.  Shrinkage in cell size by loss of substances
 Organ shrinkage
 Physiologic or pathologic
 Physiologic Atrophy
 Ex : 1. Development – notocord , thyroglossal duct
2. uterus after parturition

15.  Decreased workload
 Loss of innervation
 Diminished blood supply
 Inadequate nutrition
 Loss of hormonal stimulation
 Senile atrophy

16.  Imbalance between protein production and
utilization
 Ubiqutin proteosome pathway

18.  Reversible change
 Replacement of one adult cell by other type
 Mc – columnar to squamous
 Seen in respiratory epithelium
 Ducts of glands impacted by stones
 Vitamin A deficiency
 Malignant transformation on chronic stages
 Barrets esophagus
 Connective tissue metaplasia
 Cervical metaplasia

19.  Stem cell reprogramming
 Uncoordinated growth factors
 Vit A deficiency
 Cytostatic drugs
 Virus