Skeletal Muscle: Learn about the muscles we use to walk and run

Of the three cells on the microscope scree, which have the potential to be more oxidative?

1 and 2

Using this information, which of the three cells on the microscope screen have a high capacity for anaerobic activity?

2 and 3

Which of the three cells on the microscope screen can be considered fast twitch?

2 and 3

What is cell 2

Fast, oxidative and glycolytic

From the graphs you have made that are visible on the centre screen, how does passive tension change with muscle length?

Increases

How does twitch change with muscle length?

Increases then decreases

What is cell 1 ?

Slow and oxidative

Take a look at the graphs. Why might the EDL generate a higher force during a single twitch, but the two muscles generate similar forces when stimulated at 40 Hz?

The EDL can release more calcium with a single twitch, but at 40 Hz, both muscles achieve similar cytoplasmic calcium levels.

Comparing the two graphs, which of the following could possibly explain the faster contraction and relaxation speeds of the EDL relative to the soleus?

The EDL has more sarcoplasmic reticulum

The Soleus tetanus peaks are fused, which means that they do not completely relax before peaking again. Why might soleus show fused tetanus peaks and higher forces at a lower stimulation frequency than the EDL?

The EDL is faster at pumping calcium out of the cytoplasm.

Based solely on the fiber types you've found within these muscles, which muscle seems to be more suited to slower, sustained movements like walking?

The soleus

what is cell 3 ?

fast, glycolytic

Why might the EDL fatigue more quickly than the soleus?

the EDL uses mostly anaerobic metabolism, but the soleus uses mostly aerobic metabolism.