Adult stem cells

Question 1

What is a stem cell

Answer 1

Should be capable of self-renewal and have the ability to differentiate into multiple cell types

Question 2

What is the trophectoderm?

Answer 2

Formed on the outside of the embryo- will give rise to the placenta
Cells on the inside will be embryo

Question 3

Where do ES cells come from?

Answer 3

Inner cell mass of the blastocyst. These cells can be exposed to different factors and turned into many types of cells

Question 4

What is a progenitor cell

Answer 4

Cell which only shows limited capacity of self-renewal ad differentiation-they are different to stem cells

Question 5

Why self-renew/differentiate?

Answer 5

Self renewal is for maintaining stem cell pool, whilst giving rise to specialised cells

Question 6

What is the purpose of adult stem cells?

Answer 6

Keep the tissue alive and protect it from damage. They are multipotent they will be able to differentiate into different types of a subset of cells e.g. skin cells will have the ability to differentiate into all skin cell types

Question 7

How often does skin regenerate

Answer 7

90 days

Question 8

Define cellular homeostasis

Answer 8

Ability to regulate internal conditions usually by a system of feedback controls- stabilizing health and funcitoning- regardless of changing conditions.
Constant or periodic generation of new cells to replace the old, damaged or dying cells- or the addition of new cells

Question 9

Types of adult stem cells

Answer 9

Hematopoietic stem cells- immune system and blood
Mesenchymal stem cells- bine, cartilage, fat, muscle, tendon/ligament
Epithelial- skin, gut, other lining
Muscle
Neural

Question 10

What is a niche?

Answer 10

Complex micro environment around a stem cell, which is made up of many cells which interact with the environment and the stem cells to decide whether to activate it. Each niche is different

Question 11

What is the purpose of a niche

Answer 11

Maintain the stem cell population by providing the correct balance between self-renewal

Question 12

What are the similarities of niches?

Answer 12

There will be stem cells
There will be support cells which anchor the stem cell to the niche
Once the progenitors start to differentiate they will feedback onto the support cells to know that they have built the appropriate amount of differentiated cells- signals to stop differentiation.

Question 13

What types of blood cells do hematopoietic stem cells?

Answer 13

Myeloid cells- monocytes, mactophagesm neurtrophils, basophils etc
Lymphoid cells- T-cells, B-cell, NK cells etc

Question 14

Where are hematopoietic cells found?

Answer 14

Found in the bone marrow and form early on in development. Also found in in the placenta and umbilical cord. Stem cell factor is very important in maintaining the stem cell niche and this is secreted by stromal cells

Question 15

What signals are required for maintaining stem cells

Answer 15

JAK/STAT and BMPs

Question 16

What are the muscle stem cells called?

Answer 16

Satellite cells- muscles are built from these. Skeletal muscle regeneration is due to these satellite cells

Question 17

Where are muscle stem cells found?

Answer 17

They are normally quiescent and located outside the muscle fibre under the basal lamina.

Question 18

What are the markers for satellite cells?

Answer 18

Pax7 for satellite cells and MyoD for muscle cells

Question 19

What do mesenchymal cells differentiate into?

Answer 19

Cartilage, muscle, fat, tendons, ligaments and connective tissue

Question 20

Where are mesenchymal cells located?

Answer 20

There are located throughout the body e.g. in the bone marrow and umbilical cord blood

Question 21

What are epithelial stem cells and where are they located?

Answer 21

They give rise to epithelial cells
They are responsible for covering the internal and external surfaces.
Located in specialised niches e.g. the crypt of villi and in hair follicle of the skin

Question 22

What are neural stem cells?

Answer 22

Hypothalamic stem cells- they can self-renew or differentiate- they are radial glia cells

Question 23

Where are neural stem cells found?

Answer 23

In the subventricular zone- olfactory neurons arise from this.
Sub-granular zone
Hypothalamus- contribute to different/new eating behaviours