Download Unit 10: Feedback Loops

Bell Ringer:
• What region of the brain controls the Pituitary
Gland? Hypothalamus
• What is the “boss” of the Endocrine system?
Pituitary Gland
• What is the function of the Pituitary Gland?
Regulates all other glands with hormones through the bloodstream
• What are the “broadcasters”?
Glands
• What do the “broadcasters”release into the
bloodstream? Hormones
Unit 10: Feedback Loops
Fight or Flight Response
http://www.youtube.com/watch?v=4g25d7_Afmc
1.Increase in strength
2.No feelings of pain
3.Heightened senses
4.Sudden burst of energy
5.Increased breathing rate
Positive Feedback Loop
• An initial change causes a stimulus furthering
the change in the same direction.
Positive Feedback Loop
• Example:
– The hormone Oxytocin causes contractions in
childbirth.
Positive Feedback Loop
• Example:
– The hormone Oxytocin causes contractions in
childbirth.
– The contractions cause the release of more
Oxytocin.
Positive Feedback Loop
• Example:
– The hormone Oxytocin causes contractions in
childbirth.
– The contractions cause the release of more
Oxytocin from Hypothalamus.
– Continues until child is born.
Negative Feedback Loop
• The output shuts off the original stimulus or
reduces its intensity.
Negative Feedback Loop
• Example:
– Blood glucose rises after a meal
Negative Feedback Loop
• Example:
– Blood glucose rises after a meal
– Insulin is released into bloodstream from Pancreas
http://www.mayoclinic.org/diseasesconditions/hypoglycemia/basics/causes/con20021103
Negative Feedback Loop
• Example:
– Blood glucose rises after a meal
– Insulin is released into bloodstream from Pancreas
– Glucose becomes absorbed into cells/tissues
which then lowers blood glucose
Unit 10: Feedback Loop Homework/Notes
Name:_____________________________ Per:_____
Unit 10: Feedback Loops
Positive Feedback Loop:
Negative Feedback Loop:
Low Thyroxine in Body – Homework (Negative Feedback Loop Example)
Correct Order:
1. Thyroxine levels drop in the body which lowers Metabolism. Loop
Starts……
2. Body sends a “low Thyroxine” signal to the Hypothalamus
3. Hypothalamus secretes (TRH) Thyrotropin Releasing Hormone
4. TRH is sent to the Pituitary Gland
5. Pituitary Gland secretes (TSH) Thyroxine Secreting Hormone
6. TSH is sent to Thyroid
7. Thyroid secretes Thyroxine into blood which then spreads through body
8. Thyroxine levels increase in the body and Metabolism increases. Body
BODY
sends a “ok” signal to the Hypothalamus.
Normal Levels
9. Homeostasis in Body again …………Thyroxine Loop stops
of Thyroxine
In the box to the right, Create a Concept Map based on the
information above.
• Circle around the Glands
• Highlight the Hormones
• Use solid lines with arrows to show movement and direction of
Hormones
• Use a dashed line to show input signals from the body
• If you can’t figure this out, you must come see me during
Intervention prior to class.
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(Homeostasis)
Blood