Chapter 22 Part 2: Regeneration in Mammals

Question 1

In mammals, the ____ are capable of regenerating the same amount of tissue that is removed or lost.

Answer 1

the liver

Question 2

compensatory regeneration

Answer 2

division of ALREADY differentiated cells to replace structures and functions of damaged tissues.

Question 3

compensatory regeneration in the liver occurs via 2 mechanisms

Answer 3

1) mature hepatocytes are instructure to re-enter the cell cycle until the missing cells have become replaced
2) quiescent hepatic progenitor cells become activated when injury is severe or mature hepatocytes are not capable of fully repairing the damage.

Question 4

during regeneration, all major liver cell types including ___, __cells ___ cells ___ cells, and ___macrophages begin to regenerate lost cells, allowing for the liver to continue functioning properly.

Answer 4

during regeneration, all major liver cell types including HEPATOCYTES, FAT cells DUCT cells, ENDOTHELIAL cells, and KUPFFER macrophages begin to regenerate lost cells, allowing for the liver to continue functioning properly.

Question 5

during regeneration, gene pathways involved in ___ become down regulated, while pathways involved in _____ ___ become upregulated.

Answer 5

during regeneration, gene pathways involved in DIFFERENTIATION become down regulated, while pathways involved in CELL CYCLING become upregulated.

Question 6

Liver injury is sensed by the bloodstream, which activates ___ synthesis, increasing their concentration.
This increase in ___ activates non-hepatocytes to secrete paracrine factors.

Answer 6

Liver injury is sensed by the bloodstream, which activates POLYSACCHARIDE synthesis, increasing their concentration.
This increase in POLYSACCHARIDE activates non-hepatocytes to secrete paracrine factors.

Question 7

Liver injury is sensed by the bloodstream, which activates POLYSACCHARIDE synthesis, increasing their concentration.
This increase in POLYSACCHARIDE activates non-hepatocytes to secrete paracrine factors:

1. Kupffer cells secrete ___ and ___ to activate an immune response
2. stellate cells secrete ___ and ____
3. Endothelial cells in liber produce ___ and ___
4. metalloproteases become secreted that:

these factors all together promote hepatocyte ___ by preventing _____ via activation of ____ and repression of _____, a cyclin inhibitor.

Answer 7

Liver injury is sensed by the bloodstream, which activates POLYSACCHARIDE synthesis, increasing their concentration.
This increase in POLYSACCHARIDE activates non-hepatocytes to secrete paracrine factors:

1. Kupffer cells secrete IL6 and TNFALPHA to activate an immune response
2. stellate cells secrete HGF and TGFBETA
3. Endothelial cells in liber produce HGF and WNT2
4. metalloproteases become secreted that: DIGEST EXTRACELLULAR MATRIX ALLOWING HEPATOCYTES TO SEPARATE AND PROLIFERATE MORE EFFICIENTLY

these factors all together promote hepatocyte PROLIFERATION by preventing APOPTOSIS via activation of CYCLIN D+E and repression of P27, a cyclin inhibitor.

Question 8

digit regrowth:
each digit in mammals contains a ____ made up of progenitor cells that are undifferentiated. They contain ____-restricted and ___ progenitor cells, allowing for the regneration of digit tips in young mammals, including humans.

Answer 8

each digit in mammals contains a BLASTEMA made up of progenitor cells that are undifferentiated (PRODUCT OF EPIMORPHOSIS) . They contain ECTODERM-restricted and OSTEOBLAST progenitor cells, allowing for the regneration of digit tips in young mammals, including humans.