Adult stem cells Flashcards
What is a stem cell
Should be capable of self-renewal and have the ability to differentiate into multiple cell types
What is the trophectoderm?
Formed on the outside of the embryo- will give rise to the placenta
Cells on the inside will be embryo
Where do ES cells come from?
Inner cell mass of the blastocyst. These cells can be exposed to different factors and turned into many types of cells
What is a progenitor cell
Cell which only shows limited capacity of self-renewal ad differentiation-they are different to stem cells
Why self-renew/differentiate?
Self renewal is for maintaining stem cell pool, whilst giving rise to specialised cells
What is the purpose of adult stem cells?
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
How often does skin regenerate
90 days
Define cellular homeostasis
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
Types of adult stem cells
Hematopoietic stem cells- immune system and blood
Mesenchymal stem cells- bine, cartilage, fat, muscle, tendon/ligament
Epithelial- skin, gut, other lining
Muscle
Neural
What is a niche?
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
What is the purpose of a niche
Maintain the stem cell population by providing the correct balance between self-renewal
What are the similarities of niches?
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.
What types of blood cells do hematopoietic stem cells?
Myeloid cells- monocytes, mactophagesm neurtrophils, basophils etc
Lymphoid cells- T-cells, B-cell, NK cells etc
Where are hematopoietic cells found?
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
What signals are required for maintaining stem cells
JAK/STAT and BMPs
What are the muscle stem cells called?
Satellite cells- muscles are built from these. Skeletal muscle regeneration is due to these satellite cells
Where are muscle stem cells found?
They are normally quiescent and located outside the muscle fibre under the basal lamina.
What are the markers for satellite cells?
Pax7 for satellite cells and MyoD for muscle cells
What do mesenchymal cells differentiate into?
Cartilage, muscle, fat, tendons, ligaments and connective tissue
Where are mesenchymal cells located?
There are located throughout the body e.g. in the bone marrow and umbilical cord blood
What are epithelial stem cells and where are they located?
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
What are neural stem cells?
Hypothalamic stem cells- they can self-renew or differentiate- they are radial glia cells
Where are neural stem cells found?
In the subventricular zone- olfactory neurons arise from this.
Sub-granular zone
Hypothalamus- contribute to different/new eating behaviours
