Homeostasis Test Review Name: KEY
Look at the graph above and answer the following:
What is a behavioral explanation for the change in temperature between 7am and 9am?
Exercising (anything someone chooses to do to increase their body temperature)
What is an environmental cause of the change in temperature between 10am and 11am?
Staying inside somewhere with a thermostat, the temperature is overall stable
What is an internal response that would cause the change between 11am and 12pm?
Sweat glands secreting fluids to help cool the body temperature down, vessels dilating, etc.
2. Name 3 things Sam’s body does to stay warm while she is outside without her coat on. (List the systems involved & what they do)
1. Shivering (muscular system, quick contractions to warm up the body)
2. Sweat glands are not secreting fluids (integumentary, the skin is keeping heat preserved)
3. Blood vessels are constricted to keep heat in (circulatory system)
3. Name 3 things Desmond’s body does to stay cool while he is running. (List the systems involved & what they do).
1. Increasing breaths, (respiratory system, to help heat leave to the environment)
2. Sweat glands are secreting fluid (integumentary to help your skin cool down)
3. Increase in heart rate and dilated vessels (circulatory system, to help heat loss in the body)
4. a) Describe why you get a fever when you are sick. A fever helps increase your body temperature to kill bacteria or viruses.
b) What happens to the body’s temperature set point? It increases. (98.6 degrees F is our set point)
5. Fill in the chart to show the effect of exercise on homeostasis & the body’s response.
How does exercise affect it?
What is the body’s response?
Body temperature
Increases
Try to decrease your body temp. as it is increasing by sweating and breathing more
Blood acidity (amount of CO2)
Increases
Increasing respiratory rate to exhale more CO2
Blood sugar
Decreases
Tries to increase blood sugar to prevent hypoglycemia by releasing glucagon
Amount of O2
Decreases
Increasing respiratory rate to take in more O2
6. True or False: Enzymes work well at all temperatures or pH levels in living things.
False, enzymes work at ideal temperatures and pH levels in a variety of living organisms.
7. What is a vaccine?
A way to introduce your body to the virus to help your immune system prevent it in the future.
8. Describe how vaccines work.
Vaccines work through injection and puts a small amount of the virus to introduce your immune system to the virus. Your immune system will learn to respond and recognize the virus in order to defend your body if it ever comes in contact with that specific virus.
9. What is the difference between negative feedback and positive feedback?
Negative feedback is when your body fights against the stimulus, positive feedback is enhancing the stimulus.
10. Why is negative feedback more common when trying to maintain homeostasis?
Negative feedback is more common because it is the only way for our internal mechanisms to respond in order to maintain homeostasis.
Read the information below to answer question 11.
If you observe a plant or a tree bearing lots of fruits, you will notice the fruits go through the stages: from unripe to ripe to overripe. The process will start when the first fruit begins to ripen. When it is ripe, it releases a gas which is known as ethylene (C2H4). This causes the nearby fruits exposed to the ethylene to begin to ripen. As the ripening continues, these fruits also continue to release ethylene gas. This feedback loop is usually used in the production of fruits in which exposure to ethylene gas makes the ripening process faster.
11. Is this an example of positive or negative feedback? Why?
This is an example of positive feedback because the gas being released is only being released more. Nothing is “going against” the fruit ripening process to prevent the ethylene being released.
