Teacher Activity Notes
What Makes the Heart Beat Faster?
Students observe the effects of the hormone epinephrine (adrenaline) on the beating heart of a brine shrimp by counting the number of times the brine shrimp legs pulse per minute.
- Activity Guide
- Activity Report
- Plastic drinking straw (small diameter)
- Epinephrine solution (0.01%); Medicine dropper; Microscope slide with cover slip; Metric ruler; Brine shrimp; Scissors; Clock or watch with second hand; Hand lens or bioscope (stereoscope 10X)
- Activity Report Answer Key
- Charts and other visual representations that show the heart and circulation of blood. Also visual representations of blood vessels would enhance the learning experience.
Obtain the adult brine shrimp from an aquarium store. (The pulsating blood is not noticeable in newly hatched shrimp.) The shrimp can be stored in a container in the refrigerator for a few days without food or a water change. Daphnia, or water fleas, can be used in place of brine shrimp. They need to be ordered from a science supply house. Since they need to be kept alive with special food, the specified delivery date must be close to the date of the activity. It is difficult to keep these critters alive for long periods of time. Also order epinephrine.
Carolina Biological Supply Company, 2700 York Rd., Burlington, NC 27215. Call 1-800-334-5551.
Health Students can relate the observations of the brine shrimp to drug effects on the human body.
Prerequisites and Background Information
Students should know how to use a hand lens and bioscope. They should have practice in formulating hypotheses and designing experiments. It would also be helpful if students had some knowledge of hormone action.
Introduce Enrichment 2-1 by discussing the concept of a hypothesis. Have students make a list of hypotheses. Discuss the concept that brine shrimp, like other lab animals, are living organisms. So remind students to be careful when working with them. You might want to post the safety rules for handling laboratory animals.
Ask students to think about how epinephrine could affect the heart rate of brine shrimp. Remind them of what a hypothesis is. Remind them to consider their original hypotheses about the effect of epinephrine on brine shrimp as they conduct the activity. Make sure students understand the need for the straw ring to contain the shrimp so that they're easier to find and observe.
The medicine dropper, brine shrimp, and slides are very small. So students may need some help in centering their shrimp in the straw ring. Make sure students have the microscope set under low power. Also make sure the mirrors are focused on artificial light source-not on the sun. Remind students of lab safety rules, especially that the sun reflected in a microscope mirror can damage the eyes. Or you can post the safety rules.
Show students an example of a tally sheet. Ask them to make a mark every time they see the brine shrimp legs pulsate before the epinephrine is added. Monitor students as they add only one drop of epinephrine solution. Make sure they tally the number of times per minute the legs pulsate after the epinephrine was added. Have student compare the numbers of leg movements before and after they add the epinephrine.
A bronchial inhalator obtained from I a drugstore can be used as a substitute for epinephrine.
Conclude Enrichment 2-1 by comparing students' hypotheses to what was actually observed.
Use the experimental data and the written responses to the Activity Report to assess if students can
Activity Report Answer Key
- Sample answers to these questions will be provided upon request. Please send an email to email@example.com to request sample answers.
- What was your hypothesis about the effect of epinephrine on brine shrimp?
- Record the number of times the brine shrimp legs pulsed before and after the epinephrine was added.
- Describe your observations of the brine shrimp.
- Was your hypothesis confirmed by your experiment? Explain your answer.
Activity Guide: What Makes the Heart Beat Faster? (Student Reproducible)
Adrenaline or epinephrine is sometimes called the “fight or flight” hormone. When a person is angry or afraid, epinephrine prepares the body to fight or run away.
You cannot see the beating heart of the brine shrimp. But you can count the number of heartbeats per minute by counting the number of times the brine shrimp legs pulsate per minute.
- Plastic drinking straw (small diameter)
- Epinephrine solution (0.01%)
- Medicine dropper
- Microscope slide with cover slip
- Metric ruler
- Brine shrimp
- Clock or watch with second hand
- Hand lens or bioscope (stereoscope 10x)
- Activity Report
Think about how epinephrine could affect the heart rate of brine shrimp. Write your hypothesis on the Activity Report. Consider your original hypothesis about the effect of epinephrine on brine shrimp as you conduct this exploration.
Place the ring on a slide. The straw ring will act as a container for the brine shrimp on the slide.
With a medicine dropper, add one brine shrimp to the straw ring. Observe the slide under low power.
Observe the brine shrimp. Use a tally system to determine how many times per minute the legs pulsate. Record your observations. Add a drop of epinephrine solution and repeat the counting. Compare the numbers of leg movements before and after you added the epinephrine. What did you observe?
Consider your original hypothesis about the effect of epinephrine on brine shrimp as you conduct this exploration
What Makes the Heart Beat Faster? Activity Report Answer Key
1. What was your hypothesis about the effect of epinephrine on brine shrimp?
2. Record the number of times the brine shrimp legs pulsed before and after the epinephrine was added.
3. Describe your observations of the brine shrimp.
4. Was your hypothesis confirmed by your experiment? Explain your answer.