Download 153 - UBC Zoology

NAME & section #:
LAB REPORT: HEART FUNCTION IN THE FROG.
- Do not copy word-for-word from text.
INTRODUCTION.
- state the purpose of this exercise?
MATERIAL AND METHODS
- see the lab manual.
RESULTS. (your observations of what happens during the experiments;)
- use separate pages.
A. OBSERVATION OF THE CARDIAC CYCLE (Exercise A)
- tabulate class results for the spontaneously beating heart rate.
- calculate the mean heart rate.
- record observations as instructed in the lab manual. Answers to questions should be brief.
B. THE PACEMAKER (Exercise B)
- tabulate class results and calculate mean rates for each temperature.
- In no more than five lines, describe class results.
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C. RECORDING THE CARDIAC CYCLE (Exercise C)
- include a fully labelled (atrial and ventricular systole, diastole, chart speed, etc...) section of chart
paper from the recorder with your report.
- calculate the following from your data:
a) heart rate in beats/min.
b) duration of the atrial systole
c) duration of the ventricular systole
d) duration of the ventricular diastole.
D. THE REFRACTORY PERIOD AND EXTRA SYSTOLE (Exercise D)
- include fully labelled chart recordings showing the effects of stimulation at different points of the
cardiac cycle. (do not forget to include a recording showing the extra systole and compensatory
pause).
- include a "normal" recording for comparison.
- In no more than five lines describe what you observed.
E. EFFECTS OF AUTONOMIC DRUGS (Exercise E)
- include a fully labelled chart recording showing the effects of epinephrine, acetyl-choline and
atropine sulfate.
- tabulate class results.
- calculate the class average for heart rate.
- Using the class average, illustrate with a bar graph the effect of these autonomic drugs on the
heart rate.
- In five lines describe class results.
F. AUTOMATICITY OF THE HEART (Exercise F)
- tabulate class results.
- calculate mean rates
- in 5 lines describe class results.
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DISCUSSION. (explanations of the events in the experiments)
- Answer in the spaces provided below. Do not use extra pages.
THE PACEMAKER (Exercise B)
Explain the difference in responses when different parts of the heart are heated or cooled.
THE REFRACTORY PERIOD AND EXTRA SYSTOLE (Exercise D)
1) Explain why you obtained different responses depending on when you stimulated the ventricle
during the cardiac cycle? (some stimulations will cause an extra-systole, others will not.)
2) What is the physiological explanation for the compensatory pause?
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3) What is the advantage for cardiac muscle to exhibit an absolute refractory period which is
nearly as long as its contraction?
What is the advantage for skeletal muscle to exhibit a refractory period which is so small as to be
negligible?
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EFFECTS OF AUTONOMIC DRUGS (Exercise E)
In terms of the neural regulation of the heart, explain the effects of the autonomic drugs on heart
rate.
AUTOMATICITY OF THE HEART (Exercise F)
1) Explain why the sinus venosus, the atria and the ventricles beat with different rates when they are
separated from each other.
2) Will the rate of beating of the whole heart be similar to the rate of the isolated ventricle, of the
isolated atria or of the isolated sinus venosus? Why?
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