Hypertrophy and hyperplasia Flashcards
What is hypertrophy?
Cell enlargement that causes enlargement of an organ or body part.
What is hyperplasia?
Cell proliferation that causes enlargement of an organ or body part.
What happens to the organ in case of hypertrophy and hyperplasia?
Hypertrophy and hyperplasia usually occur together.
If the changes occur in parenchymal tissue, it will increase the function of the organ.
If the changes occur in the mesechymal part, the function of the organ will decrease or stay as it is. This is called pseudohypertrophy.
Into what two categories are hypertrophies divided?
Physiological and pathologic hypertrophy
What is physiological hypertrophy?
Occurs when organs (e.g. muscles) enlarge in response to increased physiological activity –> increases the organ’s function
What is pathologic hypertrophy?
Occurs when an organ’s function has weakened due to cell damage –> remaining cells will try to compensate
What is needed for pathologic hypertrophy to occur?
Good nutrition and care. In poor living conditions, the compensation does not happen, and further pathological changes might occur.
Into what three types of hypertrophies are pathologic hypertrophies divided according to the underlying causes?
Compensatory hypertrophy
Vicarious hypertrophy
Hormonal or correlative hypertrophy
What is compensatory hypertrophy?
Happens when the organ sustains damages due to a higher-than-normal workload.
Most often happens to the heart and left ventricle (myocardium undergoes hypertrophy due to damaged cardiac valves).
What is vicarious hypertrophy?
Particular compensatory hypertrophy that takes place in paired organs when one of them loses functionality (kidneys, ovaries, salivary glands etc).
What is hormonal/correlative hypertrophy?
Takes place in endocrine gland disturbances.
E.g. pituitary gland will hypertrophy if the thyroid gland is partially or completely missing.
