Let's return to our scenario...

DumbellsPretend you have a friend who has recently gotten very excited about fitness and exercise. Now all she wants to talk about is what’s happening in her body during workouts! She’s started a new weight lifting program for her arms where she cycles quickly through various dumbbell exercises for a few minutes before resting and repeating later. She asks you to help her understand what’s happening in her muscle cells during and after those workouts.

Briefly explain (just a sentence or two for each point) how...

    Her muscles generate energy (ATP) to do this work?
    Her nervous system coordinates the stimulation/action potentials to her muscle cells?
    Her muscle cells will change over time as a result of her workouts?

Mostly Complete (10 pts): Discuss one way cells alter their activities or characteristics for each of the topics above (energy generation, nervous system stimulation, and muscle cell adjustments). Click "previous" below to find the answers on the preceding three Canvas pages. The three preceding pages cover each of these three topics!

 

             I would explained my friend that during weight lifting, the muscles require ATP (adenosine triphosphate) to contract and perform work.  When the muscle cell is at rest, it uses some of its ATP to add a phosphate group to creatine, forming CP. When ATP levels drop during intense exercise, CP steps in. It’s rapidly broken down to generate more ATP, providing a burst of energy for about 8–10 seconds. Motor neurons transmit electrical signals from the brain , spinal cord to the muscle. When lifting weights, the nervous system coordinates the firing of motor neurons, which stimulate muscle fibers to contract.The frequency and intensity of these signals determine the force and duration of muscle contractions.Consistent work out perform training, muscle fibers increase in size due to increased protein synthesis and the addition of contractile proteins actin and myosin.