Flashcards in Cellular adaptation Deck (74)
What is cellular adaptation?
Mechanisms which allow tissues and organs to cope with changes in demand. They may be part of an entirely normal (physiological) process or occur as part of a disease (pathological) process
Are cellular adaptations usually reversible?
Give the 5 things that can alter in cellular adaptation, why do these alterations occur?
4) Metabolic activity
Occur due to changes in environment or demand
What is the role of cellular adaptation? 3
1) Aquire a new and steady state of metabolism and structure
2) Better equips cells to survive in a new environment
3) Failure of adaptation may lead to lethal or sub-lethal injury
Give an example of cell which is very susceptible to damage?
Give an example of cell which is very resistant to damage?
Name a type of cell which does not need to adapt in the face of environmental change and why?
Fibroblasts - can survive severe metabolic stress without harm eg. absence of O2
Name a type of cell which adapts easily to environmental change and why?
Labile cell population, have an active stem cell compartment
Highly adaptive in number and function
Name a type of cell which cannot adapt and why?
Permanent cell population
Highly specialised function
Easily damaged by environment change
What is meant by physiological cellular adaptation?
A cell responding to normal changes in physiology or demand
What is meant by pathological cellular adaptation?
A cell responding to disease related changes
What cellular adaptation occurs in response to increased cellular activity?
Increased size or number of cells
What cellular adaptation occurs in response to decreased cellular activity?
Decreased size or number of cells
What is the scientific term for increase in size of cells?
What is the scientific term for increase in number of cells?
Can hypertrophy and hyperplasia co-exist?
The net result of hypertrophy/hyperplasia is what?
Increased cell mass and thus increase in functional capacity
What kind of cell populations is hypertrophy commonly seen in, give an example?
Permanent cell populations
Especially cardiac and skeletal muscle
Give a physiological example of smooth muscle hypertrophy?
Hypertrophy of the smooth muscle cells of the uterus during pregnancy
Give a pathological example of muscle hypertrophy?
Hypertrophy of bladder muscle cells in benign prostatic hyperplasia - this leads to bladder outlet obstruction, bladder has to contract harder, so muscle becomes hypertrophied
Give an example of pathological hyperplasia?
Adenomyomatous hyperplasia of the prostate
Give a physiological example of skeletal muscle hypertrophy?
Skeletal muscle of a marathon runner
Give an example of pathological cardiac muscle hypertrophy?
Hypertrophy of cardiac muscle cells of left ventricle due to calcific aortic stenosis
This can also occur in systemic hypertension
Why can left ventricular hypertrophy lead to death?
Patients with LVH have increased ectopic beats, some of which can pre-dispose to sudden degeneration of rhythm to ventricular tachychardia or VF and sudden cardiac death
What is subcellular hypertrophy and hyperplasia, give an example?
Increase in size and number of subcellular organelles
For example, smooth ER hypertrophy in hepatocytes with barbiturates
What consequence can SER hypertrophy in hepatocytes with barbiturates lead to?
Increase in P450 mixed function oxidases which causes increased metabolism of other drugs - thus inactivating them
What 2 type of cell populations is hyperplasia possible in?
Labile and stable cell populations
For which 2 broad reasons may cell populations undergo physiological hyperplasia?
In response to hormones
As a compensatory mechanism
For which 2 broad reasons may cell populations undergo pathological hyperplasia?
Due to excess hormones or growth factors