Homeostasis

Maintaining The Balance

Monday, December 16th 2013

Bell Ringer:

• Describe how living organisms use ATP.

Objective:• SWBAT: Compare

and Contrast positive feedback and negative feedback in a Venn Diagram.

Review:• Speak with your neighbors for 1 minute about

homeostasis.• Write down the definition of homeostasis in

your own words.• Why is homeostasis important?

•Be Prepared To Share

How does the body work to maintain Homeostasis?

• Specialized cells in our bodies work to maintain our

1. Temperature2. pH3. O2 and CO24. Level of energy molecules such as glucose

How do our bodies regulate homeostasis?

• Feedback mechanisms1. Positive Feedback2. Negative Feedback

Set Point- Degree of Normalcy that must be maintained

Negative Feedback

• Feedback mechanism that returns a system to a set point once it deviates (goes away from) past the set point.

ex. Thermostat

How does a thermostat work?

Take 1 min and talk to the people at your table about this answer.

Negative Feedback (Example)1. You set the

temperature (let’s say 72 degrees)

2. It get’s too hot in the room.

3. The Air conditioner turns on.

4. The temperature lowers to 72.

5. The air conditioner turns back off.

Think, Pair, Share• Think quietly for one minute about an example

of a negative feedback mechanisms we have in our body, in our homes, or in nature.

• Speak with your partner about another way you think our body uses negative feedback to maintain homeostasis.

• Be prepared to share!Hint: Think about how we maintain our body temperature, our energy, and our breathing.

Check For Understanding

• What happens when the body cannot regulate the setpoint of blood glucose???

Answer: Diabetes

http://www.brainpop.com/health/diseasesinjuriesandconditions/diabetes/

DIABETES

Global Diabetes Scale

% of Diabetes

Positive Feedback

• In a positive feedback system the change will continue to deviate from the set point until something happens in the body to stop it.

Positive Feedback Example

• Child birth

Think, Pair, Share

• Think quietly for one minute about positive feedback mechanisms we have in our body.

• Speak with your partner about one way you think our body uses positive feedback to maintain homeostasis.

• Be prepared to share!Hint: Think about how your body processes energy or food.

With Your Table:

• Compare and Contrast negative and positive feedback in a Venn Diagram.

Summary Analysis Questions1. Work on independently

2. Get a stamp for Credit!**Reminder – Silent and focused (no questions!)

1.When your body temperature goes up, what happens to your amount of sweat?

2.When you sweat, what happens to your body temperature?

3.When your body temperature goes back down, what happens to your amount of sweat?

4.What type of feedback mechanism was used?