Regeneration From De-differentiated Cells Vs Stem Cells

Question 1

What are the 2 strategies for regeneration?

Answer 1

• De-differentiation, division and redifferentiation of the typical cells of that tissue
• Stem cell mediated regeneration

Question 2

Describe the regeneration which occurs when the liver is partially resected

Answer 2

The liver regenerates by differentiation of hepatocytes, proliferation and re-differentiation. Stem cells are only used in a minor part. We can say that the regeneration of the liver is not true regeneration but compensatory hyperplasia in the remaining parts of the organ

Question 3

What triggers hepatocyte profliferation?

Answer 3

The combined action of cytokines and growth factors - which make liver cells re-enter the cell cycle

Question 4

Give examples of organs which can undergo compensatory growth

Answer 4

Liver
Kidneys
Pancreas
Adrenal gland
Thyroid gland
Lungs

Question 5

Describe regeneration by stem cells

Answer 5

Here, stem cells found within the organ are the source of cells that will regenerate the organ (no differentiated cells involved).

Question 6

Describe symmetrical vs asymmetrical division of stem cells

Answer 6

Stem cells can divide symmetrically to maintain the population of stem cells in the niche, OR they can divide asymmetrically to generate one stem cell and one progenitor cell - which will differentiate into the differentiated cell which is needed

Question 7

Progenitor cells divide symmetrically / asymmetrically?

Answer 7

symmetrically - ALWAYS

Question 8

Progenitor cells later give rise to…?

Answer 8

Differentiated cells