cellular adaptation Flashcards
do cellular adaptation occur during physiological or pathological events
Both
can be physiological
can be pathological
what are the common reversible adaptations found in cells
size, number, phenotype, metabolic activity, function.
why is the aim of adaptation
Acquire new, steady state of metabolism and structure
Better equips cells to survive in a new environment
Failure of adaptation may lead to sub-lethal or lethal cell injury
do fibroblasts adapt to there environment and if not why not
Survive severe metabolic stress without harm
eg absence of O2
can cerebral neurones adapt, if not why not
Terminally differentiated
Permanent cell population
Highly specialised function
Easily damaged by environmental change
how do cells reposed to increased demand
hypertrophy
hyperplasia
what are the main types of adaptation
increased and decreased cellular activity or change in cell function
what changes does hypertrophy result in
Increase in size of existing cells
Increase in functional capacity
Increased synthesis of structural components
Increased metabolism
what cell population does hypertrophy typically happen in - permanent, stable, liable
permanent.
Ventricular hypertrophy results in increased ectopic beats, why might this be dangerous.
predispose to sudden degeneration of rhythm to ventricular tachycardia shown on the ECG, or to ventricular fibrillation and sudden cardiac death.
define sub cellular hypertrophy and hyperplasia
Increase in size and number of subcellular organelles
when does physiological hypertrophy take place
uterus in pregnancy.
prostate with age.
define Hyperplasia
Increase in number of cells
what cell population does hyperplasia occur in permanent, stable or liable
stable or liable
Is gynaecomastia physiological or pathological
hyperplasia of the glandular and stromal tissue in the breast
physiological- puberty
pathological- drugs and liver damage.
what is the pathopysiology of grave’s disease.
autoantibody binds to and switches on the TSH receptor in the thyroid, leading to prolonged, uncontrolled hyperplasia of the thyroid and hyperthyroidism
define atrophy
Reduction in size of organ or tissue by decrease in cell size and number
physiological atrophy includes
Embryogenesis, uterus after pregnancy or menopause
what are the causes of pathological atrophy
decreased workload loss of innervation diminished blood supply inadequate nutrition loss of endocrine stimulation pressure
what structures in the body undergo atrophy
aging an cerebrovascular disease- brain
kidney-decreased blood supply and back pressure form ureteric obstruction
thymus
adrenal cortex-caused by steroid therapy
why must long term steroides be stopped very slowly otherwise they would result Addisonian.
atrophy of the adrenal cortex caused by steroid therapy which would reduce the ACTH drive to the adrenal, causing a decrease in hormonal stimulation. This is a significant clinical issue. Long term steroids must be stopped very slowly to give the adrenals time to recover or the patient may be at risk of an Addisonian crisis due to hypoadrenalism.
what are 2 examples of hypertrophy
Uterus in pregnancy
ventricular hypertrophy
examples of hyperplasia
Adenomyomatous hyperplasia of prostate.
Cirrhotic liver- abnormal healing process leads to hyper plastic nodules
hypertrophy of one kidney due to hyperplasia of the other
Grave’s disease
Gynaecomastia
define metaplasia
Transformation of one differentiated cell type into another
Is metaplasia physiological or pathological
both
physiological-adaptation
pathological- cancer
define dysplasia
change of a cell type into another and proliferation
In-situ disease; non-invasive
is carcinoma in situ the same as dysplasia
yes.
before a cancer truly invades the basement membrane and when it is just proliferation what is it known as
dysplasia.
what type of cancer occurs in the cervix
squamous metaplasia
what type of cancer does endometrial hyperplasia due to increased oestrogen’s cause
adenocarcinomas
what type of cancer does parathyroid hyperplasia due to renal failure cause
adenoma
what type of cancer does squamous metaplasia of the bronchus cause
dysplasia and squamous cell carcinoma.
what type of cancer does metaplasia of the bladder cause
squamous cell carcinoma
what type of cancer does glandular metaplasia in the oesophagus cause
adenocarcinoma
