Homeostasis Lab10-30-13

Learning Target

Students will write short paragraphs describing what homeostasis is and how the nervous system is involved.

Homeostasis

Body’s ability to maintain basic stability internally with response to external stimuli.

It is the body’s way to “fix” itself when things go a little wrong.

Examples: too hot = sweat, too cold = shiver, build up pressure in your stomach = burp, built up pressure in bowels = fart.

Other examples?

“Can’t Take My Eyes Off Of You”

1. A student will have a flashlight shun in their eyes multiple times, HYPOTHESIZE/CLAIM what will happen to the pupil/iris when the flashlight is turned on.

2. PROCEDURE

a. Need 1 volunteer in each group to operate flashlight.

b. Need 1 volunteer to perform experiment.

c. Other group members are expected to look closely at the eye-opener’s eyes when the flashlight is turned on.

d. Repeat step C 2 more times.

3. DATA/EVIDENCE

a. WRITE down what happened to the pupil/iris.

4. CONCLUSION/REASONING

a. WRITE down WHY you think the pupil/iris was affected in that way.

“Oh My Beating Heart!”

Where to take your pulse: On your jugular vein or your wrist.

1. Take your pulse. I will time for 60 seconds.

2. Continue taking your pulse.

3. Answer these questions in your notebook:

a. What did you observe?

b. When have you noticed your heart rate rising before?

c. Under what circumstances?

d. Why does it happen?

Fight or Flight

CLAIM: An increase in obnoxious stimulus causes an increase in heart and breathing rates, which keeps the body balanced.

REASONING

More oxygen had to be transported by the circulatory system to cells and carbon dioxide had to be delivered from the cells to the lungs.

More oxygen and carbon dioxide is exchanged by the respiratory system by way of diffusion across the alveolar membranes.

Oxygen and carbon dioxide levels returned to normal as a result of removing the external stimuli. (and the pH has been neutralized)

EVIDENCE

Heart rate increased.

Breathing rate increased.

Recovery to original heart and breathing rates occurred.