sponge: set up cornell notes on pg. 15 topic: ch. 1 homeostasis essential question: define...

Sponge: Set up Cornell Notes on pg. 15

Topic: Ch. 1 Homeostasis

Essential Question:Define Homeostasis and explain its importance to survival

Don’t forget to add it to your T.O.Contents!

2.1 Atoms, Ions, and Molecules

Define Homeostasis and explain its importance to survival

Ch. 1 Homeostasis

2

• Title pg. 14 Homeostasis

• On the 1st line of pg. 14 title “Body Snatchers Video Notes”

• *Focus on the changes of the body after being infected with influenza virus• At least 10 bullets

Body Story: Body Snatchers

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1. What does the virus do to her cells?

2. What causes Holly’s pain symptoms? Why?

3. Your body has a natural thermostat (98.6). Why does her body react with a fever?

4. Why was it “good” that Holly couldn’t find pain medicine?

5. Why does it take the body so long to find the helper T and B cells?

6. The video said the specific T cell had been “waiting for 25 years” Hypothesize where you think she got it from?

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1. What does the virus do to her cells?“Hijacks her cell”- forces it to produce more of the virus2. What causes Holly’s pain symptoms? Why?Holly’s body is creating the pain symptoms. This lets her know that something is wrong- It is the result of her body fighting the invader. Allows her to “rest” so her body can use her energy to fight the invader. 3. Your body has a natural thermostat (98.6). Why does her body react with a fever?98.6 allows for a perfect “breeding ground” for the virus. By heating up her body the virus cannot produce at such a fast rate.4. Why was it “good” that Holly couldn’t find pain medicine?Pain medicine would reduce her fever, allowing the virus to produce at its full rate. 5. Why does it take the body so long to find the helper T and B cells?They are only 2 cells in trillions. Your body needs to locate the proper cells to fight the virus.6. The video said the specific T cell had been “waiting for 25 years” Hypothesize where you think she got it from?She was born with it. Passed on from her mother to her.

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On the top of pg. 15:

Recall from Biology what homeostasis is.

• At what temperature is your body in homeostasis?

• How does your body react to temperature increase?

• Temperature decrease?

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Recall from Biology what homeostasis is.

• At what temperature is your body in homeostasis?

• 98.6 degrees• How does your body react to temperature

increase?• Sweat• Temperature decrease?• Shivering

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An ameoba is a unicellular organism that lives in lakes or ponds• Have organelles just like us• Limited ability to move• Survives depending on the conditions of the

environment• Any extreme changes in the environment will kill it

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• Human Internal Environment • protects our cells from external changes• is relatively constant, despite an ever-

changing outside environment (98.6 degrees)

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Homeostasis

Homeostasis: Body’s maintenance of a stable internal environment

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Homeostatic Mechanisms – monitor aspects of the internal environment and corrects any changes

• Stimuli- Something that stimulates change (cause)

• Receptors – measure deviations from the set point (98.6) and sends signals to the control center

• Control center - (usually the brain) detects the change from the set point (ex: 98.6) and sends signals to effector organs.

• Effectors – such as muscles and glands, are activated and return conditions to normal

• Response – behavior that results (effect)

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Your control center (brain) is like a thermostat• Has a set temperature (98.6)• If it is too hot- sends signals to effectors to lower

body temp (ex: sweat)• If too cold- sends signals to effectors to raise

body temp (ex: shiver)

How does a thermostat work?• Air conditioner• Heater

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Homeostatic Mechanisms

Body temperature rises above set point (98.6)

100*

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Send signals to the control center

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The hypothalamus detects the difference from the set point and signals effector organs

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Work to return the body to balanced levels

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Body returns to homeostasis

Homeostatic mechanism regulates body temperatureSlide number: 1

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Control centerThe brain detects thedeviation from the setpoint and signals effectororgans.

ReceptorsThermoreceptors sendsignals to the control center.

EffectorsSkin blood vessels dilateand sweat glands secrete.

StimulusBody temperature rises above normal.

ResponseBody heat is lost to surroundings,temperature drops toward normal.

too high

too low

Normal bodyTemperature37oC (98.6oF)

StimulusBody temperature drops below normal.

ResponseBody heat is conserved,temperature rises toward normal.


EffectorsSkin blood vessels constrict andsweat glands remain inactive.

Effectorsgenerates body heat.

Control centerThe brain detects thedeviation from the set pointand signals effector organs.

If body temperaturecontinues to drop, controlcenter signals muscles tocontract involuntarily.




too high








ResponseBody heat is lost to surroundings,temperature drops toward normal.

too high


too low






too low





Control centerThe brain detects thedeviation from the set pointand signals effector organs.


too low





Control centerThe brain detects thedeviation from the set pointand signals effector organs. If body temperature

continues to drop, controlcenter signals muscles tocontract involuntarily.



too low





EffectorsMuscle activitygenerates body heat.





too low





ResponseBody heat is conserved,temperature rises toward normal.

EffectorsMuscle activitygenerates body heat.



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Using your Homeostasis effector and response sheet, write a paragraph describing the process of homeostatic mechanisms for either:

A) You have caught the flu and your temperature is now at 103 degrees

B) You are outside playing in snow and your body temperature is dropping due to the surrounding environment

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On the top of pg. 16 (no more than 5 lines)

1. What is homeostasis?

2. How do your control center and effectors work together to maintain homeostasis?

3. Give an example.

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1. What is homeostasis?The body’s maintenance of a stable internal environment

2. How do your control center and effectors work together to maintain homeostasis?The brain sends signals to specific effectors (muscles or glands) that will then respond to the changes and bring back conditions to normal

3. Give an example.The body’s temperature drops to 96 degrees. The brain signals the skeletal muscles to contract and relax repeatedly generating heat (shivering)

Sponge: Set up Cornell Notes on pg. 17

Topic: Ch. 1 Homeostasis

Essential Question:Compare and Contrast Negative and Positive feedback

Don’t forget to add it to your T.O.Contents!

2.1 Atoms, Ions, and Molecules

Compare and Contrast Negative and Positive Feedback

Ch. 1 HomeostasisPositive and Negative Feedback

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Stimulus: rising blood sugar

Response: blood sugar returns to normal= homeostasis

Negative Feedback: The control system (brain) sends signals/instructions to effectors (muscles and glands) to stabilize the body• activated by an imbalance• corrects an imbalance, brings body back to Homeostasis

Pancreas receptors detect high blood sugar

The control center signals the pancreas to secrete insulin

Effector: Insulin causes liver cells to take up sugar in the blood

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Stimulus: rising blood sugar

Response: blood sugar returns to normal= homeostasis

Pancreas receptors detect high blood sugar

The control center signals the pancreas to secrete insulin

Effector: Insulin causes liver cells to take up sugar in the blood

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Positive Feedback: Process by which changes cause additional similar changes, producing unstable conditions

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Stimulus:

Receptors:

Control Center:

Effectors:

Response:

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Homework

On the bottom of pg. 17 draw a double-bubble map, comparing and contrasting negative and positive feedback. Make sure you give examples of each.

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Negative Feedback

Positive Feedback

Corrects an imbalance

Ex: temperature regulation

Returns body to homeostasis

Causes additional changes

Ex: Contractions during childbirth

Moves body away from homeostasis

stimuli

receptors

Control center

effectors

sponge: set up cornell notes on pg. 15 topic: ch. 1 homeostasis essential question: define...

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