Lesson Plan #:AELP-ANA000
Author: David L. Umbarger, Montezuma-Cortez High School, Cortez, CO Date: May 1994
Grade Level(s): 9, 10, 11, 12
OVERVIEW: This activity is designed to let students see blood moving in the fin of a fish. They then can observe how the hormone epinephrine (adrenaline) changes the flow of blood.
A goldfish is wrapped in water soaked absorbent cotton and placed in a large petri dish. A glass slide is placed under and another over the caudal fin to hold the fin in place and help restrict the fish from flipping the fin from position. When positioned under a light microscope, the circulation of blood can easily be observed, as well as the movement of blood from arterioles to capillaries and to veinuoles. When epinephrine (adrenaline) solution is added topically to the fin, the response of the vessels can be observed.
OBJECTIVES: The student will be able to:
- What direction would you expect blood to flow through the following structures in a fish fin: Arteriole? Veinuole? Capillary?
- What are the primary differences between the structures listed above?
- What effect would you expect epinephrine (adrenaline) to have on the circulation of blood in the fin of a fish?
Locate an arteriole, veinuole, and capillary in the fish fin. After finding each structure, turn to the medium powered lens and observe. After each observation answer the questions relative to the three structures:
- What relative size is this structure?
- With what relative velocity does blood move in this structure?
- What direction does blood flow in this structure? (toward head or tail)
- Does blood move at a constant rate and in one direction or in both directions and at different rates?
- What observed reaction did the epinephrine have in the rate of blood flow in the arteriole and capillary?
- Under what conditions would you expect a fish to naturally secrete epinephrine?
- After observing the effect epinephrine has on the circulation of blood in a fish fin (question a.), expand on your answer in question b. to include an evolutionary advantage the fish might obtain by secreting epinephrine when under those conditions.
- Based on your observations, under what conditions would you secrete epinephrine, what effect would you expect it to have, and what evolutionary advantages would you expect it to provide?
All described above.
TYING IT ALL TOGETHER:
When administering the epinephrine, the students will expect an increase in the fishes’ blood flow based on their knowledge of adrenaline being a cardio-vascular stimulant. However, it restricts blood flow to the peripheral circulatory network. Their observations serve as a good test for their ability to separate what they bring in the lab as a
preconceived expectation from the actual observed effect. You might follow this lab with a discussion of the need for a placebo or other controls when doing labs of this nature.
Other drugs such as ethanol or nicotine may be used by some groups and the results compared on the board after the lab.
These lesson plans are the result of the work of the teachers who have attended the Columbia Education Center’s Summer Workshop. CEC is a consortium of teacher from 14 western states dedicated to improving the quality of education in the rural, western, United States, and particularly the quality of math and science Education. CEC uses Big Sky Telegraph as the hub of their telecommunications network that allows the participating teachers to stay in contact with their trainers and peers that they have met at the Workshops.