Stem Cells

Question 1

2 ways of stem cell division

Answer 1

1.Asymmetric self-renewal- occurs for tissue maintenance
Produces 2 cells: one that is identical to the parent cell which is needed to maintain stem cell tissue numbers and the other that is a slightly differentiated progenitor cell

2.Symmetric self renewal occurs for tissue expansion which takes place in development of when tissue repair is required after damage
Produces 2 identical cells to the parent which increases stem cell numbers that will later differentiate into progenitor cells

Question 2

Types of stem cells

Answer 2

1. Totipotent = able to differentiate into all cell types: mesoderm, ectoderm, endoderm, extra-embryonic tissue
2. Pluripotent = able to differentiate into all cell types of the embryo proper: mesoderm, ectoderm, endoderm
3. Multipotent = able to differentiate into more than 2 cells types usually restricted to a single tissue
4. Monopotent = able to differentiate into a single cell type

Question 3

What are adult stem cells

Answer 3

Arise in foetus and serve to maintain tissue throughout life

Have potential to give rise to several cell types depending on organ from which they derive

Are rare within a tissue and difficult to locate

Question 4

what are embryonic stem cells

Answer 4

Derived from early embryos but are transient and do not represent a cell that normally exists within the body

They have the potential to give rise to every cell type in the body and are easier to isolate

Question 5

clinical use of adult stem cells

Answer 5

Bone marrow = transplants

Skin stem cell = skin grafting

Eye stem cell = corneal grafting

Cartilaginous tissue = bronchus replacement