Cell adaptations: hypertrophy, hyperplasia, atrophy, metaplasia !
- Process
Under a sustained stimulus, cells grow, multiply, shrink or change type to survive.
Updated 2026-11-01
See it in 3D: Esophagus · Trachea · Cervix
What it is
Adaptations are reversible responses to a change in demand or to chronic injury. They can be normal (the uterus in pregnancy) or disease-driven (the heart in hypertension, Barrett oesophagus). Metaplasia protects in the short term but can become the ground for dysplasia and cancer.
The adaptations to tell apart
| Change | What happens | Physiological example | Pathological example |
|---|---|---|---|
| Hypertrophy | Cells get bigger | Skeletal muscle with training; uterus in pregnancy | Left ventricular hypertrophy from hypertension |
| Hyperplasia | Cells increase in number | Breast at puberty and in lactation; liver regeneration | Endometrial hyperplasia from excess oestrogen; benign prostatic hyperplasia |
| Atrophy | Cells get smaller or fewer | Involution of the thymus; uterus after menopause | Muscle from disuse or denervation; brain from chronic ischaemia |
| Metaplasia | One adult cell type is replaced by another, tougher one | Squamous metaplasia of the cervical transformation zone | Barrett oesophagus; the smoker's bronchus |
| Dysplasia (not an adaptation) | Disordered growth with atypia, before cancer | None | Cervical intraepithelial neoplasia from HPV |
Clinical notes
- Barrett oesophagus: after chronic reflux, the stratified squamous epithelium of the distal oesophagus is replaced by intestinal-type columnar epithelium with goblet cells; the risk of oesophageal adenocarcinoma rises.
- Smoker's bronchus: ciliated pseudostratified columnar epithelium turns squamous; it resists smoke but loses mucociliary clearance.
- Adult cardiac myocytes barely divide, so the heart adapts by hypertrophy, not hyperplasia.
- Vitamin A deficiency also causes squamous metaplasia (for example in the conjunctiva).
In the lab
- In a Barrett biopsy, goblet cells look like clear, mucus-filled cups between columnar cells; Alcian blue stains them blue.
- Hyperplasia keeps normal architecture and normal-looking cells; dysplasia shows large, hyperchromatic nuclei and loss of maturation.
Test yourself
Think of the answer, then tap the question to see it.
What kind of metaplasia defines Barrett oesophagus?
Replacement of stratified squamous epithelium by intestinal-type columnar epithelium with goblet cells.
Why does the heart respond to overload with hypertrophy and not hyperplasia?
Adult cardiac myocytes hardly divide; they can only get bigger.
What change happens in a smoker's bronchial epithelium?
Squamous metaplasia: ciliated columnar epithelium is replaced by squamous epithelium, which is tougher but does not clear mucus.
What separates dysplasia from hyperplasia under the microscope?
Dysplasia shows atypia (large, hyperchromatic nuclei) and disorder; hyperplasia keeps normal-looking cells.
See it in 3D
The structures of Durgical's 3D anatomy where it is found.
Related
- Cell injury, apoptosis and necrosis
- Cell cycle, mitosis and meiosis
- Esophagus and the Barrett change
- Simple, stratified, pseudostratified and transitional epithelium
- Cervix and vagina: the transformation zone
Related conditions
- Gastro-oesophageal reflux disease (GERD)
- Oesophageal cancer
- Cervical cancer
- Human papillomavirus (HPV) infection
Educational content on normal microscopic structure and its clinical relevance; no substitute for studying slides or for a health professional's advice.
Sources: What Is Cancer? (National Cancer Institute, 2021); Barrett’s Esophagus (National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), 2020); 4.6 Tissue Injury and Aging (OpenStax (Rice University), 2022).
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Representative model, for educational purposes only.