Lecture: Pathology 2: How the cell responds to injury Flashcards
How does tissue grow?
Increase in cell size or number by synthesis of new components. Different tissues show different proliferative ability.
What does the term multiplicative mean?
Increase in cell number by mitotic division
What does the term auxetic mean?
Increase in cell size
What does the term accretionary mean?
Increase in extracellular tissue
What is the role of cell turnover?
Cell turnover permits maintenance of continuously growing tissues (e.g. skin, intestinal mucosa) and healing (injury, disease).
What are labile cells?
Cells that continuously proliferate, have a short lifespan and a rapid turnover time
What are examples of labile cells?
White blood cells and many epithelial cells
What are stable cells (facultative dividers)?
Cells that have good regenerative ability but would normally have a low cell turnover
What are examples of stable cells?
Quiescent tissues e.g. hepatocytes
What are permanent cells?
Cells that have very little or no regenerative ability
What are examples of permanent cells?
Terminally differentiated cells, eg. keratinocytes, neurons, cardiac and skeletal muscle, and red blood cells.
How do cells acquire specialised functions?
Cells acquire a specialised function and this is a results of selective expression of genes. Disease replicates this process e.g. in neoplasia.
What determines severity of cell injury?
Cell injury depends on the duration and severity of the stimulus. Cell injury occurs if cells are so severely stressed that they can no longer adapt.
What are the 3 pathways following cell injury?
- Adapt
- Reversible cell injury (return to normal)
- Irreversible cell injury (necrosis or apoptosis)
What is hypertrophy?
Increase in cell size owing to increase in structural components; only adaptive response available to permanent cells (e.g. cardiac muscle cells).
What are examples of physiological hypertrophy?
- Hypertrophy of skeletal muscle through training
* Uterine hypertrophy owing to hormone stimulation
What are examples of pathophysiological hypertrophy?
- Cardiac hypertrophy owing to hypertension or valvular disease
- Bladder hypertrophy owing to prostatic enlargement