Transcript Diabetes

Year 9 Biology
Blood sugar and
Diabetes
Prior learning
That sugar is available in the blood as glucose and
regulated by the brain, pancreas and the liver
Key words
insulin, glucagon, liver, pancreas, hypothalamus, negative
feedback
Some hormones affect only one target organ,
but most affect more than one.
When the hormone has had the desired effect,
further production of the hormone needs to be
controlled.
Hormone production is controlled by a process
called negative feedback.
The regulation of blood glucose level is an
example of negative feedback.
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The level of glucose in the blood decreases, causing the
pancreas to stop producing insulin. Insulin produced by the
pancreas tells cells to take insulin from the blood and convert it
to GLYCOGEN which is stored in the LIVER
increased blood glucose
insulin
blood glucose
returns to normal
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Negative feedback – low blood glucose
The level of glucose in the blood increases, causing the pancrea
to stop producing glucagon. Glucagon stimulates the liver to
convert glycogen back to glucose and release it back in the blood
stream.
decreased blood glucose
glucagon
blood glucose
returns to normal
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1 Look at the graph
a Which point, 1 or 2, shows just after a meal was eaten?
Explain your answer.
b Which point, 1 or 2, shows when insulin was released by the
pancreas? Explain your answer.
c Between which values does blood glucose concentration
normally vary?
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When hormones go wrong – diabetes
Lack of insulin production means
that the blood glucose level is
unregulated and causes
the condition known as “sugar diabetes”.
Symtoms of diabetes include; glucose in
urine, unusual thirst and lack of energy
After a person with diabetes has eaten, their blood glucose
level increases. What happens to this glucose?
The absence of insulin means that glucose is not converted
to glycogen and stored in the liver, so the blood of a
diabetic contains extra glucose.
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When hormones go wrong – diabetes
Glucose is essential for
the body, so why is excess
glucose a danger for people
with diabetes?
The ability of the kidneys to
absorb glucose is also exceeded, so
the excess is excreted in urine.
When the glucose is used up, coma and convulsions may
occur.
Regular insulin injections and a careful diet can control the
condition.
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2 Look at the graph.
a Describe the shape of the
curve for the normal
person.
b Describe the shape of the
curve for the diabetic
person.
c Explain the difference
between the two curves.
d How much higher has the
blood glucose
concentration of the
diabetic increased beyond
the normal range in your
answer to question 1c?
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Movie clip - diabetes
1)Explain why diabetes must be treated. Use a
graph to explain your answer (6 marks)
2)Suggest which part of the diet needs most
careful control for diabetics. Explain your
answer (2 marks)
3)Why does aerobic exercise help control blood
glucose concentration? (2 marks)
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Task 2: Create a poster that displays the facts
about diabetes
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