Name: ______Biology I.
Lab: Muscle Stimulation
(A) Background
In this lab you will explore the relationship between workload and a muscle’s threshold of stimulation. You will determine the threshold stimulus for four different frog muscles (thigh, calf, upper forelimb, and lower forelimb) under workloads ranging from 0 g to 80 g.
Begin by reading the Procedure and following the instructions.
(B) Data Table: Threshold Voltage vs. Load
Load (g) / Lower Forelimb Muscles (v) / Upper Forelimb Muscles (v) / Calf Muscles (v) / Thigh Muscles (v)0 g
5 g
10 g
20 g
40 g
80 g
(C) Journal Questions
Respond to each question in underlined type.
(1) Based on the results of your investigation, what conclusions can you draw about the relationship between a muscle’s workload and its threshold of stimulation?
(2) Why would a muscle’s threshold of stimulation change as its workload changes?
(3) Which muscles were able to contract under the greatest loads? What does this suggest about the role these muscles play in frog movement?
(4) Describe an experiment you might perform to determine which leg muscles of a frog are important for jumping long distances.
(5) What are some advantages of performing this experiment in a simulated environment?