Frog’s Heart Experiment Flashcards
Difference between Amphibian heart and Mammalian heart in Heart chambers
3 chambers
2 auricles(atria) → drain into One ventricle
Fourchambers
2 atria
2 ventricles
Difference between Amphibian heart and mammalian heart Sinus venosus and White crescentic line
Present Absent
Present Absent
Difference between Amphibian heart and Mammalian heart in Pacemaker
insinusvenous(mostdependentbluishpart)
the lowermost part with the heart suspended upside down
Sa node
Difference between Amphibian heart and Mammalian heart in Conducting system
No conducting bundle system between atria and ventricle
Present
Coronaries and myocardial perfusion
Not well Well developed
Directly from the blood present in the ventricles Through coronaries
The aim of the experiment
- To prove that sinus venosus is the frog’s pacemaker
- To know the effect of temperature on the heart
- To record extrasystole
- To record heart block
Experiment Steps
Record heart rate on a slowly
rotating drum pour warm ringer to whole heart (38o) + record
bring back temperature to normal by normal ringer then pour warm ringer to sinus venosus +record
Approach heated glass rod to ventricles or auricle (without touching) +record Repeat the whole experiment using cold ringer (4)
Effect of Warming on heart rate
Whole heart increase hr
Sinus venosus increase hr
Auricles no change in hr
ventricles No change in hr
Effect of Cooling on heart rate
Whole heart Decrease hr
Sinus venosus decrease hr
Auricles no change in hr
ventricle doesn’t change in hr
Effect of temperature
Effect of cooling on the sinus venous & Effect of cooling on the cardiac muscle itself
Decrease hr (Bradycardia)
No change in hr
Inc amplitude of contraction due to 1diastolic time
Dec amplitude of contraction
(Inc EDV)
And vice versa for warmings effect
