Part III. Muscle and neuromuscular synapse
| The electrical activity in muscle is similar to that in nerve
and can be recorded in a similar manner. The nerve impulses in a motor nerve
trigger action potentials in the innervated muscle. The muscle impulses
in turn evoke the contraction of the muscle. The nerve-muscle junction is an example of a synapse-a functional connection between excitable cells, at which information is transferred from one cell to another. There are millions, maybe billions, of synapses in the central nervous system of an animal such as the frog, but few are as accessible for study as the neuromuscular (n-m) synapse. Information about the functioning of the n-m synapse can help us understand the functioning of other synapses, such as those in the central nervous system. The sartorius muscle and nerve of the frog have long been the most popular subject for study of the n-m synapse, but here we will show how the gastrocnemius muscle, together with its nerve, can also give interesting n-m results. In the present context, the sartorius muscle will be used to demonstrate some electrical features of muscle activated directly rather than by way of the innervating nerve. |
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