Healing Skeletal Muscle

This is a surgeon's incision. The operation was a success but the patient died of a heart attack two weeks later.

The muscle fibers at the upper right are pretty much normal. There are resting nuclei at the edges of red-staining fibers.

The cells in the center have a purple cytoplasm from the RNA required for protein synthesis. The nuclei have developed euchromatin (i.e., their genes are activated for repair) and nucleoli (where they made their ribosomes).

The healing process was going well. You can see some intracellular ("cloudy swelling") and extracellular edema. This appears as clear areas because water does not stain.

If you biopsied the muscle of somebody who was pumping himself up in the gym, you might see something similar. But here it is much more striking -- simply trying to get back to normal.


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