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The diversity of cellular life
Colonies of primitive unicellular organisms don’t show emergent
properties Prokaryotic organisms or
primitive eukaryotic organisms (algae, protistae) exist in colonies of identical cells
While the cells co-operate, they do not fuse to form a single mass and so don’t form a single organism
Each cell has identical structure and function
Multicellular organisms have differentiated cells
Cells are specialised: Blood cells Muscle cells Retinal cells Glandular cells Epithelial cells
Each cell type has a special task and structure
Each cell has the same DNA, but only a section of it is expressed
Levels of ‘organisation’ in a multicellular organism
1.CELL
2.TISSUE
3.ORGANS
4.ORGAN SYSTEMS
Cardiac myocytes
Heart
Cardiovascular system
4 key animal tissue types
1.Epithelial
2.Connective
3.Muscle
4.Nervous
Human Anatomy, Larry M. Frolich, Ph.D.
Human Anatomy, Larry M. Frolich, Ph.D.
Simple: just one layer or cell shape
Stratified: multiple layers and cell shapes
Classes of Epithelia
“ciliated” literally = eyelashes(see next page)
Stratified: regenerate from below
CONNECTIVE TISSUES
“Areolar tissue” as model
Universal in body
Underlies epithelium, supports capillaries, small nerves
Cells of Connective TissuesFibroblasts make fibres – cartilage, ligaments,
blood, bone
Immune cells in areolar tissue
Human Anatomy, Larry M. Frolich, Ph.D.
Different types of Connective tissues
Dense
Ligaments
CartilageBone
Loose
Fat
Areolar
Tissue types3. Muscle tissueSkeletalCardiacSmooth
Tissue types3. Nervous tissueSkeletalCardiacSmooth
Neuroglia
Cell Differentiation Harvard Animation
What are stem cells?Cells that are able to generate more specialised
types of cell types through the process of cell differentiation
Cells that can divide to make identical copies of themselves, through self-renewal
You can learn all about stem cells by watching the beautiful animation from Utah Genetics here:
Stem Cells
Different types of stem cells
1. Embryonic Stem Cells
Here, you can learn how embryonic stem cells are made:
Quck guide to Embryonic stem cells
Here is the BBC video on how embryonic stem cells are made:
How to make stem cells
Different types of stem cells
2. Somatic Stem Cells
(also called adult stem cells)
Exist naturally in the body
Used for bone marrow transplants
Can only differentiate into dedicated cell types
Adult Stem Cells are committed to become one
type of cell
Stem cells in the adult brain:Are they still working for us now?
Stem cells in mature skeletal muscle:Is there power still in our stem cells?
Different types of stem cells
3. Induced pluripotential Stem Cells
Created artificially in the lab by ‘reprogramming’ a patients own cells
Made from patient’s own cells – fat, skin, fibroblasts
Can become any cell in the body (even a whole mouse!)
Induced pluripotential Stem Cells – The future!
Learn the story of iPS stem cells from Utah Genetics…
IPS stem cells
Pros and Cons to iPS cell technology
Pros:Cells would be genetically identical to patient or donor of skin
cells (no immune rejection!)Do not need to use an embryo
Cons:Cells would still have genetic defectsOne of the pluripotency genes is a cancer geneViruses might insert genes in places we don’t want them
(causing mutations)
Different types of stem cells
4. Therapeutic Cloning: ‘patient-specific embryonic stem cells’
Can theoretically create pluripotent stem cells from patient’s own cells
Ethically highly controversial
Scientists have not yet grown a cloned human to the blastocyst stage
Different types of stem cells
Stem Cells used in medicine: Treatment of leukaemia
Stem cell transplants have been successfully used since 1968 to treat patients with leukaemia
Patients with leukaemia first have their own abnormal blood cells destroyed by radiotherapy
Then the patients own bone marrow stem cells are replaced with a transplant (into the bloodstream) from a healthy patient’s bone marrow
If the transplant is successful, then the stem cells will migrate into the bone marrow and begin to produce new, healthy leucocytes
You can learn all about leukaemia treatment by linking here onto Utah Inc:
Utah Genetics
Stem Cells used in medicine: Umbilical Cord Blood
Umbilical cord blood stem cell transplants have been used for treatment of leukaemia.
Unbilical cord blood stem cells are less prone to immune rejection
They are considered a potent resource for transplant therapies
Embryonic Stem cells are pluripotent
What can we use Stem Cells for?
To provide lab-grown human or animal tissue for identifying new treatments for disease (rather than using animals in research)
TO produce new human tissue and organs to replace damaged ones
To repair tissue by stimulating stem cells already in the body
To use stem cells from patients with inherited genetic diseases (e.g. cystic fibrosis, some forms of Parkinson’s disease) to study the disease
To better understand diseases like cancer
To investigate human development
Stem Cell Research is a fast-moving subject
Stem cell grandparents
Brand new sperm
First trial of human embryonic stem cells
Tracheal transplant
Stem cell nobel prize
The Stem Cell Ethical Debate
The Ethical QuestionsUntil recently, the only way to get pluripotent stem cells for research was to remove the inner cell mass of an embryo and put it in a dish. The thought of destroying a human embryo can be unsettling, even if it is only five days old.Stem cell research thus raised difficult questions:• Does life begin at fertilization, in the
womb, or at birth?• Is a human embryo equivalent to a human
child?• Does a human embryo have any rights?• Might the destruction of a single embryo
be justified if it provides a cure for a countless number of patients?
• Since ES cells can grow indefinitely in a dish and can, in theory, still grow into a human being, is the embryo really destroyed?
Ethics and iPS: Problem solved?
With iPS cells now available as an alternative to hES cells, the debate over stem cell research is becoming increasingly irrelevant. But ethical questions regarding hES cells may not entirely go away.Inevitably, some human embryos will still be needed for research. iPS cells are not exactly the same as hES cells, and hES cells still provide important controls: they are a gold standard against which the "stemness" of iPS cells is measured.Some experts believe it's wise to continue the study of all stem cell types, since we're not sure yet which one will be the most useful for cell replacement therapies.An additional ethical consideration is that iPS cells have the potential to develop into a human embryo, in effect producing a clone of the donor. Many nations are already prepared for this, having legislation in place that bans human cloning.
Key Ethical Questions (1)MORALITY AND HUMANITY OF EMBRYOS
1. At what point does an embryo/ blastocyst have full moral status?
2. Is there a ‘moral cut-off’ at 14 days after fertilisation?
3. Does an embryo’s moral status increase as it develops?
Key Ethical Questions (2)1. Is there anything wrong with using spare
embryos left over from fertility treatment?
2. Is it morally justifiable to use embryonic stem cells as a means to an end, if they will provide huge benefits from human health?
3. Should we be using embryonic stem cells at all, if we have the alternatives of stem cell lines derived from umbilical cord blood or induced pluripotential stem cells?
Arguments about embryonic cells
Arguments about Somatic Cell Nuclear Transfer
Arguments about the Moral Status of the
Embryo (1)
Arguments about the Moral Status of the
Embryo (2)
Arguments about the moral status of the
embryo (3)
Arguments about the moral status of the
embryo (4)
Links on ethics related to Stem Cell research
Stem Cell Ethics Factsheet
Ethics and Embryos Factsheet
Are embryos human? – a conversation…