Hyperplasia / Hypoplasia / Aplasia Flashcards
What is hyperplasia?
The increase in the number of cells in an organ or tissue, usually resulting in an increase of mass of the organ or tissue
Which cell populations does hyperplasia usually occur in?
Cell populations capable of dividing
What is hypoplasia? And Aplasia?
The decrease in cell number in an organ or tissue leading to a decrease in size. Aplasia is the extreme situation
What are the 2 types of physiological hyperplasia?
Hormonal and Compensaory
Give an example of hormonal hyperplasia
Proliferation of the glandular epitheliu of the female breast at puberty and during pregnancy
Give an example of compensatory hyperplasia
Increase in tissue mass after damage or partial resection (as in liver regeneration)
What may cause pathologic hyperplasia?
An excess of hormones or growth factors acting on target cells
Give an example of pathologic hyperplasia
Endometrial gland hyperplasia as a result of an imbalance between estrogen and progesterone secretion, resulting in abnormal menstrual bleeding
Why is pathalogic hyperplasia so dangerous?
It constitutes a fertile soil in which cancer proliferation may arise
What is the mechanism of hyperplasia?
Growth factor driven proliferation of mature cells and in SOME cases it is due to increased output of new cells from tissue stem cells.
What are the mechanisms for hypoplasia and aplasia?
Apoptosis
Decreased protein synthesis
Increased protein degradation
Autophagy
