cell adaptations
TRANSCRIPT
Hypoxia
Physical Agents
Chemicals
Infections
Immunological Reactions
Genetic Errors
Nutritional Imbalances
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
Increased production of structural proteins
Switch of contractile proteins from adult to fetal
Expression of fetal genes
Cells capable of replication
Increase in no of cells
Increase in size of the organ
Physiologic and pathologic
Hormonal
Compensatory
Mechanisms of hyperplasia
local production of growth factors
activation of intra cellular pathway
stem cells
Excessive hormonal stimulation
Bph , endometrial hyperplasia
Fertile soil for cancerous proliferations
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
Decreased workload
Loss of innervation
Diminished blood supply
Inadequate nutrition
Loss of hormonal stimulation
Senile atrophy
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