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22 Cards in this Set
- Front
- Back
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Define a stem cell |
A cell with both the capacity for self-renewal through cell division, and the capacity to generate specialised cell types through differentiation |
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What are the various forms of stem cell potency? |
Totipotent, pluripotent, multipotent, unipotent |
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Why is it important to keep the number of true stem cells low? |
To avoid excessive division and replication which may lead to DNA mutations |
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What is a committed stem cell? |
A cell which can give rise to a smaller subpopulation of cells |
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Give an example of cell renewal in the body |
Skin cells repeatedly express different keratin proteins through their 30 day lifespan |
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Describe the arrangement of stem cells in the gut |
Small numbers of stem cells found in crypts lining epithelium of gut, which differentiate and migrate up into the villi of the gut |
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What are the 4 types of cell produced by stem cells in the gut? |
Absorptive cells (brush border) Goblet cells (secrete mucus) Enteroendocrine (secrete serotonin and peptide hormones) Paneth cell (innate immune cells |
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Describe the pathway of a terminally differentiated cell in the gut |
Differentiation into G0 cell in the crypt of gut, migrate upwards to tip of villus in 2-5 days and sloughed off at surface |
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From which stem cell do blood cells originate? |
Haemopoietic stem cells |
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What is the experimental evidence of haematopoietic stem cells in bone marrow? |
If you irradiate a mouse to halt its blood cell production, the mouse will die. If you then inject it with bone marrow cells from a donor it will survive, showing the presence of a stem cell which can repopulate blood cell supply. You can then identify subpopulations of cells using cell surface antibodies and selectively test them by giving them to the irradiated mouse |
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What is the clinical relevance of bone marrow transplantation? |
Can be autologous (from patient) or allogeneic (from donor) Can be used to treat severe aplastic anaemia (bone marrow failure), leukemia (cancer of WBCs) or Non-Hodgkins lymphoma (cancer of the lymphatic system) |
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In which two locations will you find brain stem cells? |
Subventricular zone (produces new neurones for the olfactory bulb) and dentate gyrus of the hippocampus (involved in learning and memory, requires plasticity |
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Describe the pathway of neural stem cells in the subventricular zone? |
Neuronal stem cells lining ventricles produce neuroblasts. These migrate to the olfactory bulb along the rostral migratory stream. They form mature neurones and integrate into circuits |
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What are the two types of embryonic stem cells? |
Totipotent - can form the entire blastocyst Pluripotent - can form the embryo but not surrounding tissues (endo, meso, ectoderm) |
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Who discovered the mechanism for iPSCs? What are the 4 factors? |
Shinya Yamanaka, 2006 Oct4 Sox2 Klf4 Myc |
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From which cells are iPSCs usually produced? |
Fibroblast cells |
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What is a "disease in a dish" model and why is it useful? |
They allow us to produce cell types not usually accessible, for study in a petri dish. Allows us to study in vitro models for human disease and has potential for autologous transplantation |
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How are iPSCs useful in studying Parkinsons? |
We can produce dopaminergic neurones from iPSCs and study the disease pathways associated with them. We can also use them to screen for novel drugs |
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Name an ongoing trial involving iPSCs |
TRANSEURO, European trial looking into transplantation of iPSC/ESCs into brains of Parkinsons patients |
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What is the difference between apoptosis and necrosis? |
Apoptosis is controlled and programmed, necrosis occurs due to injury |
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Describe some features of apoptosis |
Molecular pathway involves activation of proteases and caspase 3, the executioner enzyme DNA fragmentation and laddering on electrophoresis Blebbing of nuclear membrane |
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What are 4 cell death diseases? |
Alzheimers - death of cortical neurones Parkinsons - death of midbrain dopaminergic neurones Huntingtons - death of medium spiny neurones in striatum, accumulation of Htt protein Motor neurone disease - death of upper/lower motor neurones |
