Transcript Hormones and Blood Sugar

Hormones and Blood Sugar
Key Players
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In regards to maintaining blood sugar
levels…
The Pancreas
The Liver
Player #1
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The pancreas
Contains two types of cells…
Digestive Enzymes
Focus on hormone producing cells
Islets of Langerhans
Located where ??
Islets of Langerhans
Islets of Langerhans
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Contain Alpha and Beta Cells
Alpha Cells: Secrete Glucagon
Beta Cells: Secrete Insulin
Player #2
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The Liver
Stores Glucose in the form of glycogen
Before We Look At Mechanisms…
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Must understand:
Body has created Positive and Negative
feedback systems
Positive Feedback
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Designed to accelerate or enhance a
response that has already started
Pushes systems outside of their normal
range
Example
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During Childbirth:
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Pressure receptors encourage the release of
Oxytocin in the Pituitary Gland
Oxytocin causes contractions
Pressure increases on the pressure sensors
After the child is born, the pressure receptors
are no longer stimulated and Oxytocin
production ceases
Pressure Sensors cause the release of
oxytocin
Oxytocin causes contractions to
intensify
More intense contractions cause
more pressure
Negative Feedback
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Designed to maintain the body systems
within appropriate parameters
Mechanisms are activated to restore
conditions to their normal state
Keeps delicate systems working ideally
and preserves body function
Example
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Calcium Levels
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If calcium levels in the blood are too low the
parathyroid releases parathyroid hormone
Parathyroid hormone causes the bones to
release calcium
Parathyroid hormone also causes intestines to
absorb more calcium
Blood calcium levels then return to normal
Example cont’d
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Calcium Levels cont’d
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If your calcium levels in your blood are too
high
The thyroid produces calcitonin
Calcitonin increases the uptake of calcium to
the bones
Calcium levels return to normal
Therefore
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In the body we see more Negative
Feedback Systems…
As part of homeostasis
And as you can see it is very Structured,
precise and complex.
Back to Blood Sugar
Glucose Regulation
You Decide
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Positive or Negative Feedback ??
Discuss and Explain Your Reasoning
Diabetes
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Caused by insufficient production or use of
insulin.
If untreated causes: blindness, kidney
failure and nerve damage.
Insulin
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Without adequate levels
Blood sugar levels rises quickly following
meals
Kidneys are unable to reabsorb all the
blood glucose being filtered
What does insulin do…
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Required for cells of the body to become
permeable to glucose
Therefore if insulin isn’t present glucose
cannot enter cells and they become
“starved”
Type 1 & Type 2 Diabetes
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Type 1: Juvenile on-set
Occurs when the pancreas cannot produce
insulin because of the degeneration of beta cells
in the islets of Langerhans
Type 2:Adult on-set
Decreased insulin production or ineffective use
Can be controlled by diet, exercise or oral drugs
(sulfonamides)
Adrenal Glands – Regulating BSL
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Already Know – Located on top of the
kidneys
Release the hormones epinephrine and
norepinephrine
How do these affect Blood Sugar Levels ?
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Nervous system senses a stressful situation
Short-term:
Adrenal medulla releases epinephrine and
norepinephrine into the blood
This causes a rise in blood sugar levels
Glucagon converted to glucose
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Why do you think this is important ??
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Long-term:
Adrenal cortex releases glucocorticoids
and mineralocorticoids
Glucocorticoids help the body meet the
demands of stress.
Cortisol – increases amino acids in blood
Questions
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P. 383 # 2,3,4,5
Q. 2 – How Does Insulin regulate
blood sugar levels ?
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Insulin decreases blood sugar levels.
When blood sugars are high, insulin is
released. Insulin increases glucose
utilization by making cells more permeable
to glucose, and blood sugar levels are
returned to a normal range.
Q.3 - How does glucagon regulate
blood sugar levels?
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Glucagon increases blood sugar levels.
When blood sugar levels are low, glucagon
is released and liver glycogen is converted
into glucose. Blood sugar levels rise as
glucose leaves the liver.
Q.4 - Using a flow chart, show a homeostatic
adjustment for a person who has consumed
a significant amount of carbohydrates in the past
hour.
Q.5 - What advantage is provided by increasing
blood sugar above normal levels in times
of stress?
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This provides more glucose for cells.
Glucose can be converted to adenosine
triphosphate (ATP), the cellular fuel. This
ensures that greater energy will be
available to the tissues of the body.