Pathology – Proper Mechanism Flow Charts (Clean
& Exam‑Ready)
Use these arrow‑based flow charts directly in exams and presentations.
1) Hypertrophy (↑ Cell Size)
Stimulus (↑ workload / hormones) → Activation of signaling pathways → ↑ Transcription of growth genes
→ ↑ Protein synthesis (actin, myosin, enzymes) → ↑ Size of individual cells → ↑ Organ size (NO increase in
cell number)
2) Hyperplasia (↑ Cell Number)
Hormonal / Growth factor stimulus → Binding to growth factor receptors → Activation of cell cycle genes →
↑ Mitosis → ↑ Number of cells → Enlarged tissue/organ
3) Metaplasia (Change in Cell Type)
Chronic irritation / inflammation → Stem cell reprogramming → Altered gene expression → Replacement of
one mature cell type by another → Better stress tolerance but ↓ normal function
4) Dysplasia (Disordered Growth)
Persistent irritation / genetic damage → Abnormal cell proliferation → Loss of uniformity & polarity →
Nuclear atypia → Premalignant change (reversible early)
5) Atrophy (↓ Cell Size / Number)
↓ Workload / nutrition / blood supply / hormones → ↓ Protein synthesis → ↑ Protein degradation
(ubiquitin–proteasome) → Autophagy → ↓ Cell size ± number → ↓ Organ size & function
6) Aplasia (Failure of Development)
Genetic / developmental defect → Failure of cell production → Absence of tissue or organ
1
& Exam‑Ready)
Use these arrow‑based flow charts directly in exams and presentations.
1) Hypertrophy (↑ Cell Size)
Stimulus (↑ workload / hormones) → Activation of signaling pathways → ↑ Transcription of growth genes
→ ↑ Protein synthesis (actin, myosin, enzymes) → ↑ Size of individual cells → ↑ Organ size (NO increase in
cell number)
2) Hyperplasia (↑ Cell Number)
Hormonal / Growth factor stimulus → Binding to growth factor receptors → Activation of cell cycle genes →
↑ Mitosis → ↑ Number of cells → Enlarged tissue/organ
3) Metaplasia (Change in Cell Type)
Chronic irritation / inflammation → Stem cell reprogramming → Altered gene expression → Replacement of
one mature cell type by another → Better stress tolerance but ↓ normal function
4) Dysplasia (Disordered Growth)
Persistent irritation / genetic damage → Abnormal cell proliferation → Loss of uniformity & polarity →
Nuclear atypia → Premalignant change (reversible early)
5) Atrophy (↓ Cell Size / Number)
↓ Workload / nutrition / blood supply / hormones → ↓ Protein synthesis → ↑ Protein degradation
(ubiquitin–proteasome) → Autophagy → ↓ Cell size ± number → ↓ Organ size & function
6) Aplasia (Failure of Development)
Genetic / developmental defect → Failure of cell production → Absence of tissue or organ
1
