Stem Cells Flashcards
What are the two essential characteristics of stem cells?
Self-renewal: Ability to divide and produce identical copies of themselves.
- Differentiation: Ability to give rise to specialized cell types
What are the types of stem cells based on potency?
Totipotent: Can form all tissues, organs, and extra-embryonic structures (e.g., fertilized egg).
- Pluripotent: Can differentiate into cells of all three germ layers (e.g., embryonic stem cells).
- Multipotent: Can give rise to specific tissue types (e.g., adult tissue stem cells).
Where are embryonic stem (ES) cells found, and what are their characteristics?
Found in the inner cell mass of the blastocyst.
• They are pluripotent and can differentiate into any cell type.
• Can be cultured indefinitely and manipulated to generate specific cell types.
What are methods to ensure cultured cells are embryonic stem cells?
Microscopy: Inspect for health and undifferentiated state.
- Passaging: Ensure cells exhibit long-term self-renewal.
- Karyotyping: Check for chromosomal integrity.
- Pluripotency markers: Confirm expression of pluripotency genes.
- Embryoid body formation: Test spontaneous differentiation into all three germ layers
What are tissue (adult) stem cells, and what are their roles?
Multipotent cells that generate and maintain specific tissues.
• Found in fetal tissues, cord blood, and adult tissues.
• Role: Repair and replace damaged cells in the body.
Give examples of tissue stem cells and their functions.
Hematopoietic stem cells: From blood or bone marrow, generate all blood cells.
- Mesenchymal stem cells: From bone marrow, can form bone, cartilage, and fat cells.
- Neural stem cells: Generate neurons, oligodendrocytes, and astrocytes.
Where does adult neurogenesis occur, and what are its functions?
Subventricular zone (SVZ): Sensory processing related to smell/memory.
- Subgranular zone (SGZ) in hippocampus: Spatial awareness, cognitive flexibility, and mood regulation.
What is the stem cell niche, and why is it important?
The microenvironment around stem cells.
• Provides support and signals for self-renewal and differentiation.
• Components: Niche cells, secreted factors, blood vessels for nutrition, and neural inputs.
What are induced pluripotent stem cells (iPSCs)?
Somatic cells reprogrammed to a pluripotent state using Yamanaka factors (4 transcription factors).
• Functionally similar to embryonic stem cells.
What are the advantages of iPSCs over embryonic stem cells?
Avoid ethical issues of using embryos.
- Derived from patient-specific cells, reducing rejection risks.
- Used to study diseases, drug screening, and potential organogenesis.
What are current applications of stem cells in medicine?
Umbilical cord stem cells: Treat leukemia in children.
• Hematopoietic stem cells: Used in bone marrow transplants.
• iPSCs: Study genetic diseases, test drug responses, and explore tissue regeneration.
How do stem cells help us understand development and disease?
Provide insight into early human development and cell division control.
• Allow modeling of genetic disorders and testing of therapeutic interventions.
What is reproductive cloning, and how is it related to stem cells?
Cloning uses cytoplasmic factors to reprogram DNA, turning somatic cells into pluripotent cells.
• Basis for creating iPSCs and studying cell differentiation.
