Skeletal muscle fiber

1          sarcoplasm (cytoplasm)

2          nuclei (of muscle cell)

3          myofibrils

4          Cohnheim's areas (skip this)

5          plasma membrane (sarcolemma)

6          endomysium


The Sarcomere:

            A band

            I band

            M line

            Z line


IMPORTANT:  This is a model of a segment of

a skeletal muscle CELL (fiber).

This single cell has multiple nuclei, and a single

axon terminal that controls its contraction.  The

myofibrils of the sarcomere are a specialized

cytoskeleton.  Please remember what you've

learned about basic cell structure!


Neuromuscular junction / synapse (nmj)


Neural structures:

8          axon

9          myelin sheath

10        mitochondria of the neuron

11        3 terminal branches of axon

12        neurofibrils (seen in cut section of

            terminal branch)

13        Schwann cells (1.5 cells are shown)

14        synaptic vesicles (shown as dots)

15        nuclei of Schwann cells


Muscle structures:

16        mitochondria of the muscle fiber

17        subneural cleft (lateral view)

18        subneural cleft (superficial view)

19        synaptic bouton