29. Regeneration - definition, mechanisms, medical significance.

Question 1

Regeneration - the process by which some organisms replace or restore lost or amputated body parts

Physiological regeneration - e.g. replacement of RBCs by spleen, replacement of cells that have been damaged
New RBCs made in bone marrow

Reparative regeneration - the repair of body organs that have been damaged

Answer 1

Regeneration - the process by which some organisms replace or restore lost or amputated body parts

Physiological regeneration - e.g. replacement of RBCs by spleen, replacement of cells that have been damaged
New RBCs made in bone marrow

Reparative regeneration - the repair of body organs that have been damaged

Question 2

Somatic embryogenesis - plant or embryo is derived from a single somatic cell or group of somatic cells, can be used in clonal propagation

Compensatory regeneration - after organs are damaged, removed or cease to function - increased functional demand can stimulate growth in tissues. e.g. if one kidney is removed, the other kidney grows until it is the size of both kidney’s combined

Answer 2

Somatic embryogenesis - plant or embryo is derived from a single somatic cell or group of somatic cells, can be used in clonal propagation

Compensatory regeneration - after organs are damaged, removed or cease to function - increased functional demand can stimulate growth in tissues. e.g. if one kidney is removed, the other kidney grows until it is the size of both kidney’s combined

Question 3

Mechanism - reverse cells (undifferentiated) epithelial cells revert to an earlier development stage
Dedifferentiation of adult structures - an undifferentiated mass of cells becomes re-specified. This type of regeneration is characteristic for re-forming limbs

Another example - morphallaxis - repatterining of existing tissues - little new growth

Answer 3

Mechanism - reverse cells (undifferentiated) epithelial cells revert to an earlier development stage
Dedifferentiation of adult structures - an undifferentiated mass of cells becomes re-specified. This type of regeneration is characteristic for re-forming limbs

Another example - morphallaxis - repatterining of existing tissues - little new growth

Question 4

Regenerating parts exhibit polarity by always growing in a distal direction (away from the main part of the body).

Answer 4

Regenerating parts exhibit polarity by always growing in a distal direction (away from the main part of the body).

Physiological - constant loss of many kinds of cells due to wear and tear by everyday activity

Question 5

Medical sig:

• engineer or replace damaged tissues or organs using bodies own repair mechanism to functionally heal previously irreplaceable tissues or organs
• possibility of growing tissue + organs in the lab and safely implant when the body cannot heal itself
• if regenerated organic cells derived from patients own tissue!
• cells -> solve problem of organ shortage and organ transplant rejection
• Rearrangement of preexisting tissue, use of adult somatic stem cells + dedifferentiation +/ or histodifferentiation of cells, more than one can operate in different tissues of the same animal
• during development - genes activated that serve to modify properties of the cell as living differentiate into different tissues

Answer 5

Medical sig:

• engineer or replace damaged tissues or organs using bodies own repair mechanism to functionally heal previously irreplaceable tissues or organs
• possibility of growing tissue + organs in the lab and safely implant when the body cannot heal itself
• if regenerated organic cells derived from patients own tissue!
• cells -> solve problem of organ shortage and organ transplant rejection
• Rearrangement of preexisting tissue, use of adult somatic stem cells + dedifferentiation +/ or histodifferentiation of cells, more than one can operate in different tissues of the same animal
• during development - genes activated that serve to modify properties of the cell as living differentiate into different tissues