Look Mama, It

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Look Mama, Its Alive!

• Human Feedback Systems

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TAKS Objective 2 The student will demonstrate
an understanding of living systems and the
environment

• Interdependence occurs
• among living systems

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• TEKS 8.6
• The student knows that interdependence occurs
  among living systems. The student is expected to
  identify feedback mechanisms that maintain
  equilibrium or systems such as body temperature,
  turgor pressure, and chemical reactions

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Lesson Objectives

• The learner will produce a graph or sketch to
  describe a negative feedback system, such as for
  serotonin production.
• The learner will demonstrate understanding of how
  blood glucose is controlled in humans by creating
  labeled drawings and providing a summary of the
  process.
• The learner will produce a labeled sketch that
  describes thermal regulation in humans.

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Question

• True or False Each body system works in isolation

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• Body systems are interrelated and work through a
  series of feedback systems

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Question

• True or False Feedback systems react quickly

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• In feedback systems, the action of a system
  components is typically slow in terms of time.
  That is, there is a build up in one direction and
  slowly, the body returns to homeostasis.

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Prior Knowledge

• Identify human systems and their function

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Background
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Negative feedback systems homeostasis

• Control of blood glucose
• Control blood calcium
• Control of blood pressure
• Control of body temperature

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Negative feedback

• Returns the body to equilibrium. It works like
  driving car down the road. Constant adjustment
  to the right or left is required to keep the car
  on the road.

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A negative feedback system is one that tries to
keep the body constant.
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In a positive feedback system the change will
continue to increase in one direction until
something happens in the body to stop it.
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An example of positive feedback is

• childbirth

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The feedback cycle
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Glucose Insulin and Glucagon

• The receptors of the pancreas are responsible for
  monitoring glucose levels in the blood.

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Blood Glucose Level

• Pancreatic Hormones regulate blood sugar level
  before and after meals.
• Islets clusters of cells in pancreas
• Alpha?secrete GLUCAGON increases sugar
• Beta? secrete INSULIN decreases sugar

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What Happens?

• Between meals
• Blood glucose low?Pancreas secretes
  glucagon?Liver changes glycogen to
  glucose?glucose sent to target tissues
• After a meal
• Blood glucose high?Pancreas secretes
  insulin?Glucose goes to the Liver(Glygogen) and
  goes to Target tissues

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Fight or Flight

• In emergencies, adrenaline is released by the
  body to override the homeostatic control of
  glucose. This is done to promote the breakdown of
  glycogen into glucose to be used in the
  emergency. These emergencies are often known as
  'fight or flight reactions'.

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Fight or Flight

• Adrenaline is secreted by the adrenal glands. The
  secretion of it leads to increased metabolism,
  breathing and heart rate. Once the emergency is
  over, and adrenaline levels drop, the homeostatic
  controls are once again back in place

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Thermoregulation
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?ENGAGE
View the video clip, The Search for Answers
beginning at 250.

• The Search for Answers

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?EXPLORE

• Compare the level of serotonin and serontonin
  receptors. Stop the video at 350, 356, and 403

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?EXPLAIN

• 1. What is the role of serotonin?
• 2. What is the effect of high levels of
  serotonin on the body?
• 3. Explain how the body attempts to regulate
  serotonin levels?
• 4. Relate serotonin regulation to anorexia
  nervosa.

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?ELABORATE

• Role Play The Rise and Fall of Glucose

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?ELABORATE

• How does the body keep from overheating?
• How does the body keep warm?

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?EVALUATE

• Produce a sketch or graph and describe a negative
  feedback system.
• Produce a labeled sketch of thermal regulation in
  humans.
• Summarize the regulation of blood glucose

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Concept Map
The Endocrine System
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