Portsmouth College
Science Department
Stem Cells
Joe Wright
Portsmouth College
Learning Outcomes
• Explain what is meant by stem cells,
pleuripotency and totipotency
• Discuss the moral, ethical and spiritual
implications of stem cell research
Joe Wright
Portsmouth College
Question
• How many different types of cell are
there in the human body?
Joe Wright
Portsmouth College
Epidermal keratinocyte (differentiating epidermal cell) Epidermal basal cell (stem cell) Keratinocyte of fingernails and toenails Nail bed basal cell (stem cell) Medullary hair shaft cell Cortical
hair shaft cell Cuticular hair shaft cell Cuticular hair root heath cell Hair root sheath cell of Huxley's layer Hair root sheath cell of Henle's layer External hair root sheath cell Hair matrix cell
(stem cell) Surface epithelial cell of stratified squamous epithelium of cornea, tongue, oral cavity, esophagus, anal canal, distal urethra and vagina basal cell (stem cell) of epithelia of cornea,
tongue, oral cavity, esophagus, anal canal, distal urethra and vagina Urinary epithelium cell (lining urinary bladder and urinary ducts) Salivary gland mucous cell (polysaccharide-rich secretion)
Salivary gland serous cell (glycoprotein enzyme-rich secretion) Von Ebner's gland cell in tongue (washes taste buds) Mammary gland cell (milk secretion) Lacrimal gland cell (tear secretion)
Ceruminous gland cell in ear (wax secretion) Eccrine sweat gland dark cell (glycoprotein secretion) Eccrine sweat gland clear cell (small molecule secretion) Apocrine sweat gland cell
(odoriferous secretion, sex-hormone sensitive) Gland of Moll cell in eyelid (specialized sweat gland) Sebaceous gland cell (lipid-rich sebum secretion) Bowman's gland cell in nose (washes
olfactory epithelium) Brunner's gland cell in duodenum (enzymes and alkaline mucus) Seminal vesicle cell (secretes seminal fluid components, including fructose for swimming sperm)
Prostate gland cell (secretes seminal fluid components) Bulbourethral gland cell (mucus secretion) Bartholin's gland cell (vaginal lubricant secretion) Gland of Littre cell (mucus secretion)
Uterus endometrium cell (carbohydrate secretion) Isolated goblet cell of respiratory and digestive tracts (mucus secretion) Stomach lining mucous cell (mucus secretion) Gastric gland
zymogenic cell (pepsinogen secretion) Gastric gland oxyntic cell (hydrochloric acid secretion) Pancreatic acinar cell (bicarbonate and digestive enzyme secretion) Paneth cell of small intestine
(lysozyme secretion) Type II pneumocyte of lung (surfactant secretion) Clara cell of lung Anterior pituitary cells Somatotropes Lactotropes Thyrotropes Gonadotropes Corticotropes
Intermediate pituitary cell, secreting melanocyte-stimulating hormone Magnocellular neurosecretory cells secreting oxytocin secreting vasopressin Gut and respiratory tract cells secreting
serotonin secreting endorphin secreting somatostatin secreting gastrin secreting secretin secreting cholecystokinin secreting insulin secreting glucagon secreting bombesin Thyroid gland
cells thyroid epithelial cell parafollicular cell Parathyroid gland cells Parathyroid chief cell oxyphil cell Adrenal gland cells chromaffin cells secreting steroid hormones (mineralcorticoids and
gluco corticoids) Leydig cell of testes secreting testosterone Theca interna cell of ovarian follicle secreting estrogen Corpus luteum cell of ruptured ovarian follicle secreting progesterone
Kidney juxtaglomerular apparatus cell (renin secretion) Macula densa cell of kidney Peripolar cell of kidney Mesangial cell of kidney Intestinal brush border cell (with microvilli) Exocrine gland
striated duct cell Gall bladder epithelial cell Kidney proximal tubule brush border cell Kidney distal tubule cell Ductulus efferens nonciliated cell Epididymal principal cell Epididymal basal cell
Hepatocyte (liver cell) White fat cell Brown fat cell Liver lipocyte Type I pneumocyte (lining air space of lung) Pancreatic duct cell (centroacinar cell) Nonstriated duct cell (of sweat gland,
salivary gland, mammary gland, etc.) Kidney glomerulus parietal cell Kidney glomerulus podocyte Loop of Henle thin segment cell (in kidney) Kidney collecting duct cell Duct cell (of seminal
vesicle, prostate gland, etc.) Blood vessel and lymphatic vascular endothelial fenestrated cell Blood vessel and lymphatic vascular endothelial continuous cell Blood vessel and lymphatic
vascular endothelial splenic cell Synovial cell (lining joint cavities, hyaluronic acid secretion) Serosal cell (lining peritoneal, pleural, and pericardial cavities) Squamous cell (lining perilymphatic
space of ear) Squamous cell (lining endolymphatic space of ear) Columnar cell of endolymphatic sac with microvilli (lining endolymphatic space of ear) Columnar cell of endolymphatic sac
without microvilli (lining endolymphatic space of ear) Dark cell (lining endolymphatic space of ear) Vestibular membrane cell (lining endolymphatic space of ear) Stria vascularis basal cell
(lining endolymphatic space of ear) Stria vascularis marginal cell (lining endolymphatic space of ear) Cell of Claudius (lining endolymphatic space of ear) Cell of Boettcher (lining
endolymphatic space of ear) Choroid plexus cell (cerebrospinal fluid secretion) Pia-arachnoid squamous cell Pigmented ciliary epithelium cell of eye Nonpigmented ciliary epithelium cell of eye
Corneal endothelial cell Respiratory tract ciliated cell Oviduct ciliated cell (in female) Uterine endometrial ciliated cell (in female) Rete testis cilated cell (in male) Ductulus efferens ciliated cell
(in male) Ciliated ependymal cell of central nervous system lining brain cavities) Ameloblast epithelial cell (tooth enamel secretion) Planum semilunatum epithelial cell of vestibular apparatus
of ear (proteoglycan secretion) Organ of Corti interdental epithelial cell (secreting tectorial membrane covering hair cells) Loose connective tissue fibroblasts Corneal fibroblasts Tendon
fibroblasts Bone marrow reticular tissue fibroblasts Other nonepithelial fibroblasts Pericyte Nucleus pulposus cell of intervertebral disc Cementoblast/cementocyte (tooth root bonelike
ementum secretion) Odontoblast/odontocyte (tooth dentin secretion) Hyaline cartilage chondrocyte Fibrocartilage chondrocyte Elastic cartilage chondrocyte Osteoblast/osteocyte
Osteoprogenitor cell (stem cell of osteoblasts) Hyalocyte of vitreous body of eye Stellate cell of perilymphatic space of ear Red skeletal muscle cell (slow) White skeletal muscle cell (fast)
Intermediate skeletal muscle cell nuclear bag cell of Muscle spindle nuclear chain cell of Muscle spindle Satellite cell (stem cell) Ordinary heart muscle cell Nodal heart muscle cell Purkinje
fiber cell Smooth muscle cell (various types) Myoepithelial cell of iris Myoepithelial cell of exocrine glands Red Blood Cell Erythrocyte (red blood cell) Megakaryocyte (platelet recursor)
Monocyte Connective tissue macrophage (various types) Epidermal Langerhans cell Osteoclast (in bone) Dendritic cell (in lymphoid tissues) Microglial cell (in central nervous system)
Neutrophil granulocyte Eosinophil granulocyte Basophil granulocyte Mast cell Helper T cell Suppressor T cell Cytotoxic T cell B cells Natural killer cell Reticulocyte Stem cells and committed
progenitors for the blood and immune system (various types) Auditory inner hair cell of organ of Corti Auditory outer hair cell of organ of Corti Basal cell of olfactory epithelium (stem cell for
olfactory neurons) Cold-sensitive primary sensory neurons Heat-sensitive primary sensory neurons Merkel cell of epidermis (touch sensor) Olfactory receptor neuron Pain-sensitive primary
sensory neurons (various types) Photoreceptor rod cell of eye Photoreceptor blue-sensitive cone cell of eye Photoreceptor green-sensitive cone cell of eye Photoreceptor red-sensitive cone
cell of eye Proprioceptive primary sensory neurons (various types) Touch-sensitive primary sensory neurons (various types) Type I carotid body cell (blood pH sensor) Type II carotid body cell
(blood pH sensor) Type I hair cell of vestibular apparatus of ear (acceleration and gravity) Type II hair cell of vestibular apparatus of ear (acceleration and gravity) Type I taste bud cell
Cholinergic neural cell (various types) Adrenergic neural cell (various types) Peptidergic neural cell (various types) Inner pillar cell of organ of Corti Outer pillar cell of organ of Corti Inner
phalangeal cell of organ of Corti Outer phalangeal cell of organ of Corti Border cell of organ of Corti Hensen cell of organ of Corti Vestibular apparatus supporting cell Type I taste bud
supporting cell Olfactory epithelium supporting cell Schwann cell Satellite cell (encapsulating peripheral nerve cell bodies) Enteric glial cell Astrocyte (various types) Neuron cells (large variety
Joe Wright
of types, still poorly classified) Oligodendrocyte Spindle neuron Anterior lens epithelial cell Crystallin-containing lens fiber cell karan cellsMelanocyte Retinal pigmented pithelial cell
Portsmouth
College
Oogonium/Oocyte
Spermatid
Spermatocyte Spermatogonium cell (stem cell for spermatocyte) Spermatozoon Ovarian follicle cell Sertoli cell (in testis) Thymus epithelial cell
Introduction
• After fertilisation a ZYGOTE is formed
• A series of rapid cell divisions (CLEAVAGE)
follows
• Smaller cells are produced after each division
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Joe Wright
Portsmouth College
Cells in the Early Embryo
• After a zygote has
undergone 3 cycles it
has 8 identical cells.
• Any of these cells can
develop into a complete
human (e.g. identical
twins)
• These cells are called
TOTIPOTENT
Joe Wright
Portsmouth College
An 8 Cell Human Embryo
(Day 3)
5 Days after Conception
BLASTOCYST
Outer
layer
forms the
placenta
Joe Wright
Portsmouth College
Inner cell mass
goes on to form
the tissues of
developing
embryo. Cells
referred to as
PLURIPOTENT
EMBRYONIC
STEM CELLS
Differentiated Cells
• As embryo develops cells become specific
types of cell (DIFFERENTIATED)
• Some cells even in adults can turn into a
limited number of cells e.g. neural stem cells
& white blood stem cells.
• These cells are called MULTIPOTENT
Joe Wright
Portsmouth College
Joe Wright
Portsmouth College
Medical Uses of Stem Cells
• Adult stem cells have been used for
over 30 years to treat….
• Leukaemia & Lymphoma
Joe Wright
Portsmouth College
Potential use of Stem Cells
•
•
•
•
•
•
•
•
Parkinson’s Disease
Brain Damage
Cancer
Spinal cord injury
Muscle damage
Heart damage
Arthritis
Osteoporosis
•
•
•
•
•
Low blood supply
Baldness
Missing teeth
Deafness
Blindness and
Vision Impairment
• ALS (Lou Gehrig's
Disease)
A Universal Human Donor Cell
Joe Wright
Portsmouth College
Where to get Stem Cells
• Pluripotent cells isolated from ‘spare
embryos’ from IVF treatment
• Embryos allowed to grow to form
blastocysts
• Stem cells isolated, then cultured to
hopefully develop into tissues
• Rest of embryo discarded
Joe Wright
Portsmouth College
Ethical Concerns
Joe Wright
Portsmouth College
Ethical Concerns
• Most people agree that there are no
ethical objections to using adult
multipotent stem cells.
• Different people see the status of the
human embryo differently
• UK Law changed on 22nd Jan 2001
Joe Wright
Portsmouth College
UK Law: Before Jan ‘01
• Human Embryos only used in following cases:
– To promote advances in the treatment of
infertility
– To increase knowledge about causes of
congenital disease
– To increase knowledge about the causes of
miscarriage
– To develop more effective methods of
contraception
– To develop methods for detecting gene or
chromosome abnormalities in embryos before
Joe Wright
Portsmouth College
UK Law: Current
• ‘spare embryos’ from in vitro fertilisation
treatment can now be used as a source of
embryonic stem cells for the purpose of
research into serious disease
• On 27 Feb 02 extended to include
fundamental research necessary to
understand differentiation and
dedifferentiation of cells
Joe Wright
Portsmouth College
United States of America
• There is no U.S. Law against human embryonic stem
cell research
• Bush’s 2001 policy limited federal funding of stem cell
research only to what existed at the time
• Some scientists say that many of the cell lines are
deteriorating, contaminated or were developed
through obsolete methods, making them inadequate
to determine the potential therapeutic value of
embryonic stem cells
• Different states can have their own laws, e.g.
– California & New Jersey allow state funds to be used on
embryonic stem cells
– South Dakota bans research on any embryo
Joe Wright
Portsmouth College
SNAB Ethical Framework
Rights & Duties
Human rights
Right to life
Religious teaching
Making decisions for
yourself
I’m ill, I want the treatment
It’s my embryo
Joe Wright
Portsmouth College
Maximising the amount of
good in the world
More treatments = Healthier People
Leading a virtuous life
Justice: If it’s legal then its OK
Wisdom: Scientific advances are
important
Moderation: multipotent cells OK,
pluripotent cells not OK
Religious Concerns
• Religious concerns are rooted in views
about ‘life’. What is life…?
– the accidental result of the interaction of
chemical substances?
– the gift of a Creator God?
Your personal answer to this question may affect
how you feel about stem-cell research. But try to
put yourself in other people’s shoes…
Joe Wright
Portsmouth College
Life…an accident?
• Some secular philosophers would argue that
human life is precious because it is rare (in
galactic terms). Therefore to destroy life is
morally wrong.
• Others would argue that there is no difficulty in
using the cells of a zygote or blastocyst – as
many die naturally in any case.
• Difficult choices: is it morally defensible to use
one (potential) life to help another?
Joe Wright
Portsmouth College
If Life is an accident, you tell me…
• If life is an accident, does it matter what
happens to a few cells?
• Is there any difference between destroying a
potential human or, say, eating meat?
• Is there a reason for considering human life to
be more precious than any other life?
• Is it morally right to use one life to save
another?
• Is a potential human less valuable than a
developed human?
Joe Wright
Portsmouth College
Life…a gift? Consider the Bible…
• “You (God) created my inmost being; you knit
me together in my mother’s womb”
(Psalm 139)
• “The Lord God formed the man from the dust of
the ground and breathed into his nostrils the
breath of life, and the man became a living
being” (Genesis 2:7)
Joe Wright
Portsmouth College
Life…a gift? Consider the Qur’an…
(Surah 23:12-14)
• Verily, We created man from a product of wet earth;
(raw materials of life)
• then placed him as a drop of seed (sperm/egg?) in a
safe lodging (womb?)
• then We fashioned the drop into a ‘clinging thing’
(zygote?)
• then We fashioned the ‘clinging thing’ into a ‘little lump’
(blastocyst?)
• then we fashioned bones for the little lump (foetus?)
• then we clothed the bones with flesh (developed
foetus?)
• and then produced it as another creation. (baby)
Joe Wright
Portsmouth College
Life…a gift?
• Some religious philosophers (theologians)
argue that a gift from God comes with certain
‘conditions’ – like a manufacturers instructions.
(e.g. “Warranty is void if cover is removed”)
• Those conditions may include:
- “The Lord gives and the Lord takes away”
- “Love your neighbour as you love yourself”
- “You shall not murder”
Joe Wright
Portsmouth College
Life…a gift?
Some theologians draw a distinction
between human and animal life.
So…for them…it may be acceptable to use
animal stem cells, but not human ones.
Such theologians would also draw the line at
combining human and animal cells for
medical treatment.
Joe Wright
Portsmouth College
Life…a gift?
Other theologians argue that we must balance
scripture with reason…
e.g. God has given us the ability to reason out the
mechanics of life (biology). Knowing that many
eggs, zygotes and blastocysts do not survive
naturally, may be an indication that God is
unconcerned about stem cell research.
e.g. God brings healing through the skills of
scientists and doctors (to whom he has given the
gifts of reason).
Joe Wright
Portsmouth College
Let there be life!
We know that the human body is made up
of:
65% Oxygen
18% Carbon
10% Hydrogen
3% Nitrogen
1.5% Calcium
1% Phosphorous
0.2% Potassium
0.3% Sodium Chloride
1% Trace Elements
Joe Wright
Portsmouth College
Trace elements:
Magnesium, Iron, Fluorine, Zinc,
Silicon, Zirconium, Rubidium,
Strontium, Bromine, Lead, Niobium,
Copper, Aluminium, Cadmium, Boron,
Barium, Arsenic, Vanadium, Tin,
Mercury, Selenium, Manganese,
Iodine, Gold, Nickel, Molybdenum,
Titanium, Tellurium, Antimony,
Lithium, Chromium, Cesium, Cobalt,
Silver, Uranium, Beryllium, Radium.
Challenge…from Religion…
65% Oxygen
18% Carbon
10% Hydrogen
3% Nitrogen
1.5% Calcium
1% Phosphorous
0.2% Potassium
0.3% Sodium Chloride
1% Trace Elements
Trace elements:
Magnesium, Iron, Fluorine, Zinc,
Silicon, Zirconium, Rubidium,
Strontium, Bromine, Lead, Niobium,
Copper, Aluminium, Cadmium, Boron,
Barium, Arsenic, Vanadium, Tin,
Mercury, Selenium, Manganese,
Iodine, Gold, Nickel, Molybdenum,
Titanium, Tellurium, Antimony,
Lithium, Chromium, Cesium, Cobalt,
Silver, Uranium, Beryllium, Radium.
GO on…MAKE A HUMAN BEING!
Joe Wright
Portsmouth College
Discuss this proposition…
“At our current level of technology, we are unable to create
life…in ANY form. This is an ability that God reserves for
himself.
THEREFORE we have no right to destroy potential life,
whatever the possible benefits for human kind”
Joe Wright
Portsmouth College
AS Biology Task
• Using Activity Sheet 3.10 and your own
research.
• Produce 3 A4 Posters on:
– What are Stem Cells
– Arguments FOR Stem Cell Use
– Arguments AGAINST Stem Cell Use
Joe Wright
Portsmouth College