Abnormalities of growth / celullar adaptation Flashcards
Give an example of cells which do not need to adapt as the are able to survive severe metabolic stress without harm?
Fibroblasts
Give an example of cells with are able to adapt easily
Epithelial cells
Give an example of cells that are unable to adapt?
Cerebral neurons
How to cells respond to increased demand?
1) increase size of cells (hypertrophy)
2) increased number of cells (Hyperplasia)
What is involved in subcellular hypertrophy and hyperplasia?
1) increased size and number of organelles
What is the process of reduction in size of organ or tissue by decrease in cell size and number?
Atrophy
What physiological situations do we see atrophy?
- embryogenesis
- uterus after pregnancy / menopause.
When do we see pathological atrophy?
- decreasede workload
- loss of innervation
- diminished blood supply
- loss of endocrine stimulation
What are the mechanisms of atrophy?
1) reduction in volume of individual cells
2) Death of individual cells (apoptosis)
What is Involution?
Involution is PHYSIOLOGICAL atrophy by apoptosis
What is ageneis?
failure of formation of an embryonic cell mass
What is aplasia?
Failure to differentiate to organ specific tissue
What is dysagenesis?
failure of structural organisation of tissues into organs
What is hypoplasia?
failure of growth of organ to full size
What is metaplasia?
Transformation of one differentiated cell type into another
Where do we see metaplasia as part of the physiological process?
Uterus transforms through pre-puberty, puberty, pregancy, menopause
Where do we see pathological metaplasia?
1) Cigarette smoke causes epithelium to change from pseudostratified ciliated bronchial to sqaumous epithelium.
2) Bladder calculus/schistomosiasis/longstanding catheter.
3) Acid reflux causes the oesophageal squamous epithelium to change to columnar (glandular) epithelium.
What is dysplasia?
the earliest manifestion of multistage process of neoplasia
True or false :
Adaptations are reversible changes
TRUE
True or fale:
Dysplasia is reversible
FALSE
