Lesson 5

1. The Endocrine System:
Feedback
Loops and
Homeostasis

2. Homeostasis and Hormones
• The endocrine
system functions
within positive and
negative feedback
loops in our bodies
to help maintain
homeostasis.
• What are feedback
loops?

3. Temperature Control
Knowing the following:
• The thyroid produces thyroxine, which
increases metabolism and helps regulate
body temperature.
• Thyroid-stimulating hormone is released
by the pituitary.
• Sketch a negative feedback loop that
controls body temperature regulation.

4. Temperature Control

5. • Knowing the following:
• Calcitonin from the thyroid inhibits
calcium release from the bones.
• Parathyroid hormone stimulates
release of calcium from the bones.
• Sketch a negative feedback loop that
controls blood calcium level.
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6. Blood Calcium

7. • Knowing that:
• Insulin from the pancreas lowers blood
glucose by stimulating body cells to take
up glucose.
• Glucagon from the pancreas increases
blood sugar by stimulating the liver to
break down glycogen into glucose.
• Sketch a negative feedback loop in your
notebook that controls blood sugar.
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8. Blood Sugar Control

9. Finally…Exit Slip
• On your desk: Draw a feedback loop
regulated by the endocrine system.
• Raise your hand when you are done
• Explain it and clean it off to be dismissed
from class