Hypertrophy / Hypotrophy / Atrophy Flashcards
What is Hypertrophy
An adaptive change which consists of an increased size of a cell or an organ in response to different stimuli
Which type of cells does hypertrophy often occur in?
Non-dividing cells
What is Hypotrophy?
A decrease in cell or organ size
What is atrophy
The extreme of hypotrophy
Hypertrophy in skeletal and cardiac muscle occurs as a result of what?
An increased workload
Describe an example of hypertrophy occuring as a result of hormonal stimulation
Hypertrophy of the uterine smooth muscle during pregnancy (as a result of estrogen stimulation)
How is hypertrophy achieved within a muscle cell
Increase in myofilaments
Increased synthesis of cellular proteins
This is induced by growth factors, mechanical sensors and vasoactive agents
Name some pathways which can lead to hypertrophy
The phosphoinositide 3-kinase pathway
Pathways activated by G-protein coupled receptors
Give examples of physiological atrophy
Atrophy of the notocord
Atrophy of the tyroglossal duct
Give examples of pathologic atrophy
- result of decreased workload, atrophy of disuse ie bed rest
- loss of innervation of a muscle
- diminished blood supply
- inadequate nutrition
- loss of endocrine stimulation
What are the mechanisms of hypotrophy and atrophy
Decreased protein synthesis (redced metabolic activity)
Increased protein degradation(by ubiquitin proteosome ptw)
Increased autophagy
