These B.Pharm notes on cell injury and adaptation (Chapter 7 of Human Anatomy, Physiology and Pathophysiology I) summarise the key points for first semester pharmacy students and link to the complete PDF.
Table of Contents
Read the following document for full information
Chapter overview
Cells respond to stress and injury in different ways depending on the type, duration and severity of the insult. This chapter describes the causes of cell injury, including hypoxia, chemical agents, physical agents and infectious organisms, and explains the difference between reversible and irreversible injury. It compares necrosis with apoptosis, describes the role of free radicals, and defines cellular adaptations such as atrophy, hypertrophy, hyperplasia, metaplasia and dysplasia, which allow cells to survive changed conditions.
Key points on cell injury and adaptation
- Causes of cell injury: hypoxia, chemical, physical and infectious agents
- Reversible versus irreversible injury
- Necrosis and apoptosis compared
- Cellular adaptations: atrophy, hypertrophy, hyperplasia, metaplasia, dysplasia
- Mechanisms of free-radical injury
Relevance to pharmacy practice
Many drugs and toxins injure cells, so this topic underlies toxicology and adverse drug reactions. Paracetamol overdose causes liver cell necrosis, and some anticancer drugs work by triggering apoptosis in tumour cells. Antioxidants are used to limit free-radical damage. Recognising hypertrophy, hyperplasia and atrophy also helps pharmacists understand conditions such as enlarged heart muscle and enlarged prostate.
Frequently asked questions
What is the difference between necrosis and apoptosis?
Necrosis is uncontrolled cell death after injury and causes inflammation. Apoptosis is programmed, energy-dependent cell death that does not provoke inflammation.
What is hypertrophy?
An increase in the size of cells, and therefore of the organ, without an increase in cell number, for example in the heart muscle of athletes.
What is metaplasia?
The reversible replacement of one mature cell type by another, such as columnar cells replaced by squamous cells in the airways of smokers.
Quick revision checklist
Before moving on, check that you can do each of the following without looking at your notes. Use this list on cell injury and adaptation as a self-test: tick a statement only when you can answer it aloud. Revisit any statement you cannot answer, then re-read the matching section of the PDF. Repeating this cycle two or three times before an exam builds the recall and confidence you need for both theory papers and viva.
- I can explain: causes of cell injury: hypoxia, chemical, physical and infectious agents
- I can explain: reversible versus irreversible injury
- I can explain: necrosis and apoptosis compared
- I can explain: cellular adaptations: atrophy, hypertrophy, hyperplasia, metaplasia, dysplasia
- I can explain: mechanisms of free-radical injury
Study and exam tips
Read the key points on cell injury and adaptation first, then study the PDF notes and redraw the main diagrams from memory. Link each concept to a drug or clinical example, and revisit the chapter before your internal and university examinations. Short daily revision works better than one long session. For additional reading, see the NCBI Bookshelf.
In B.Pharm examinations, short answer questions usually ask for definitions, classifications and labelled diagrams, while long answers on cell injury and adaptation ask for detailed descriptions with examples. Learn the headings in the order given in your syllabus, and add one clinical or drug-related example to each long answer to earn extra marks.
This post is part of the free B.Pharm Guru notes for the first semester. Every chapter of Human Anatomy, Physiology and Pathophysiology I has a short summary, key points and a downloadable PDF written for the B.Pharm course, so you can revise quickly or study in depth.
Previous chapter (Chapter 6): classification of tissues, structure, location and functions of epithelial, muscular and nervous and connective tissues. Next chapter (Chapter 8): integumentary system. View all HAP-I chapters.
