9b.1 Stem Cells and Tissue Engineering

Question 1

Hiroshima

Answer 1

if not instant death, died in 14 days. Blood replenishes in 14 days. No cells left to replace blood so people died.

Question 2

Potency

Answer 2

number of fates cells can take

Question 3

Totipotent

Answer 3

cells that can form every cell of embryo (3 layers, etc) and cells of placenta

Question 4

Pluripotent

Answer 4

cells that can form cell of all 3 germ layers but not placenta

Question 5

Multipotent

Answer 5

cells derived from embryo or adult committed to form small component of cells (hematopotent stem cells = present in bone marrow and capable of forming all blood cells)

Question 6

Uni/Bi potent

Answer 6

cells that can take up only one or two fates

Question 7

Stem Cell Niche

Answer 7

micro environment in which these stem cells can exist

Question 8

Stem Cells Therapeutic

Answer 8

• Stem cells can be defined as cells of variable potency that undergo asymmetric
cell division to form a stem cell and a progenitor cells.
• Stem cells have the capacity to self renew and differentiate into a committed cell.
• Play important role in organ maintenance and repair.
• Therapeutic repair of damaged organ by injecting some extra Stem cells.

Question 9

Single Cell Asymmetry

Answer 9

cells can keep making more cells or go on to commit to differentiation

Question 10

Population Asymmetry

Answer 10

in order to keep up the population, some cells are more prone to make more and some are more prone to commitment

Question 11

Adult stem cell lineage

Answer 11

In many organs, cell lineages pass from multipotent stem cells (can form many cells) to committed stem cell (can form a few cells) to progenitor cell (which is a trait amplifier) to a differentiated cell

Question 12

Stem cell Capacity

Answer 12

Intestine/Stem cell/Hematoppoietic:

• High cell turnover
• High regeneration
• High capacity

Liver/Muscle/Adrenal Gland:

• High cell turnover
• Low regeneration
• Medium capacity

Brain/Kidney/Heart:

• Low cell turnover
• Low regeneration
• Low capacity

Question 13

Pulse-chase experiment:
• To measure turnover of cells
• T1/2

Answer 13

• Labelled BrUridine deoxythymidine Short time (PULSE)
• Unlabelled Thymidine (Chase)
• label 4 cells, how long for it to get to 1/2 tabled cells
• measure radioactivity at zero then a X minutes

Question 14

Intestinal Stem Cells Niche

Answer 14

• Wnt - promotes survival and proliferation of stem cells in intestine
• cells undergoing continuous dividing replace microvilli and are in the crypt
• progenitor cells form transient amplifying zone. They move forward till reach epithelium
• progenitor not cabable of unlimited self renual (unlike stem cells)
• BMP - promotes differentiation, maturation in the direction of willis

Question 15

Fluorescence activated Cell sorting (FACS)

Answer 15

• CFP and GFP expressing cells
• stem cells have specific surface markers
• cell goes through resiviour one at a time. Excited by laser and florescent light detected by photomultiplier tube
• certain changes (that’s related to surface markers) and separated into fractions

Question 16

3 stem cell assays

Answer 16

•Repopulation Assay: Stem cells
transplanted into adult mice.
• In vitro Induction Assay:
• Embryo incorporation assay

Question 17

Bones

Answer 17

• osteoblasts -form bone cells
• osteoclasts -degrade bone cells (arise from hemapoetic stem cells)
• osteoblasts arise from mesenchymal stem cells