Reviewing Frog Muscle Lab Data 2015
How much did our frogs weigh?
What percentage of body mass is the gastrocnemius muscle of the frog?
Should the gastroc muscle be able to lift the body mass of the frog during jumping?
Does the data indicate that the gastroc could lift the mass of the frog?
Compare the peak tetanic tension to the mass the gastrocnemius muscle. How many times its own weight can the gastroc muscle lift?
According to our data, which has the lowest threshold: stimulation of the sciatic nerve or direct stimulation of the muscle?
How do you explain the difference in thresholds for the nerve and muscle?
Examine the values reported for the latent period. Which should result in the longer latent periods and why: stimulation of the sciatic nerve or direct stimulation of the muscle?
What is the most likely explanation for the wide variation in twitch duration?
Compare the contraction times for the left and right gastrocnemius muscles from each frog. Would we expect the values to be similar? Why or why not?
Examine the values for peak twitch tension. Which values seem unusual? How do you explain the variation among muscles?
One might assume the two gastrocnemius muscles from each frog would be equally strong. Do our results support that assumption?
How do you explain the variation in peak twitch tension? Your explanation should incorporate the length-tension curve.
If this experiment were to be repeated, what would you suggest to make sure that each muscle is starting from its optimal length? In other words, how might the set-up be modified to produce more consistent results in the future?
According to the textbook, by what ratio is peak tetanic tension expected to exceed peak twitch tension?
(Continued on reverse side.)
Should the peak tetanic tension be greater than the peak twitch tension? Why or why not? (Consider what’s happening with Ca++ during these contractions.)
What did we establish as an index of fatigue?
We’d expect time to fatigue would be very similar from muscles from the same frog. Provide several possible explanations as to why our results have so much variability.
What is the role of the wrist extensor in the forearm of the frog?
Based on its function, predict the relative abundance of Type I and Type II myofibers in the wrist extensor of the frog.
What is the role of the gastrocnemius muscle in the frog?
Based on its function, predict the relative abundance of Type I and Type II myofibers in the gastrocnemius of the frog.
What percentage of body mass is the wrist extensor muscle of the frog?
Based on the predicted types of myofibers that comprise each muscle, which muscle would be expected to fatigue more quickly? Does our data support that assertion?