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MIND BLOWING TIME!: De-extinction
• We may now have the technology to clone extinct species
and (literally) bring them back to life on this planet!
• Scientists have pinpointed around 20 species for which this
may be possible, including the Wooly Mammoth, the
Tasmanian tiger and the Dodo.
• Scientists, geneticists, experts in biotechnologies, and
ethicists from around the world are currently meeting to
discuss the ethics and issues surrounding de-extinction
• Check out the TED Talk if you’d like:
http://www.ted.com/talks/stewart_brand_the_dawn_of_de_
extinction_are_you_ready.html
Hormones that affect Blood
Sugar
Representing the PANCREAS y’all!
The Pancreas
• The pancreas contains 2 types of cells, one
which produces digestive enzymes, and
another which produces hormones
• Hormone producing cells are found in
structures called ‘islets of Langerhans’
• Islets contain alpha and beta cells which
produce the hormones insulin and glucagon
Hormones that affect blood sugar
Insulin
• Discovered by Canadian scientists Banting & Best in 1921
(Banting received the Nobel Prize for this work in 1923)
• Produced in the beta cells of the islets of Langerhans in
the pancreas
• Released when blood sugar levels increase (ie. after a
meal)
• Cause the cells of muscles and the liver to become
permeable to glucose
• In the liver, excess glucose is converted to glycogen
Hormones that affect blood sugar
Glucagon
• Produced in the alpha islet cells
• Released when blood sugar level decreases
• Promotes conversion of glycogen to glucose
There are also other secondary hormones that
have an affect on blood sugar in the body
The Blood Sugar Loop:
After a meal, blood sugar
rises, and so insulin is
released. This, in turn, leads
to the uptake of glucose,
lowering blood sugar
When blood sugar drops,
glucagon is released. This
results in the conversion of
glycogen to glucose and
release into blood
Other Important Hormones
Epinephrine & norepinephrine
• Also known as adrenaline & noradrenaline
• Produced and stored in the adrenal medulla (part
of the adrenal gland above the kidney)
• Stress stimulates their release into the blood
• Result in an increased heart rate and blood sugar
level
• Has a similar affect as the presence of glucagon
Other Important Hormones
Glucocorticoids
• Includes cortisol
• Released by the anterior pituitary to help the
body recover from stress
• Increase the level of amino acids in blood
• Amino acids then converted into glucose by
the liver, again raising blood sugar levels
Diabetes Mellitus
• Chronic disease caused by insulin deficiency or
“resistance”
• characterized by persistent hyperglycemia (blood
glucose > 20 mmol/L)
• Symptoms: low energy, high urine volume,
glucose in urine, excessive thirst, weight loss,
blurred vision, acetone breath
Diabetes Mellitus
There are 3 main types:
Type 1:
• pancreas is unable to produce
insulin
• considered a variety of
autoimmune disease
• possible genetic component
but always triggered by
environmental factor(s)
Diabetes Mellitus
Type 2:
• decreased insulin production or ineffective use of
insulin by cells (“insulin resistance”, caused by
defective insulin receptor on cell membrane)
• can be controlled with diet, exercise & drugs that
stimulate the pancreas
• strong genetic component
Type 3:
• gestational diabetes
• similar to type 2, but usually temporary
Diabetes Mellitus
Treatment: frequent monitoring of blood sugar
levels, close attention to carb intake (no simple
sugars in diet), exercise
• For type 1, insulin injection by syringe, pump or
pen.
• Possible islet cell transplant (still in experimental
stages)
Untreated: leads to blindness, kidney failure, nerve
damage, massive cell death (necrosis and
gangrene)
Lab Exercise
Effects of Hormones of Blood Sugar
• Lab exercise 8.2.1 – pg. 401