1. From a functional standpoint, discuss the difference between isotonic and isometric muscle contractions. 2. The graph on the right compares speed of musce contraction with load. Which object will you be able to lift most quickly. and which will you lift most slowly? Explain your answer by discussing the relationship between load and speed of contraction. Liting a cell phone Lifting a laptop computer Lfting a television 20 40 60 80 100 120 140 Time (msec) Stimulus 3. The figure on the right shows the organization of three small motor units. Notice that the muscle fibers in each motor unit are dispersed throughout a muscle and intermingle with muscle fibers of the other motor units. What do you think is the functional significance of such an arrangement? Spinal cord Cell bodies of motor neurons Axons of motor neurons Motor nerve KEY Motor unit 1 Motor unit 2 Muscle fibers from different motor units Motor unit 3 Distance shortened