Neuromuscular Junction Diseases

Three ways to break the nerve-muscle handshake · Week 4
A muscle moves when a nerve releases acetylcholine (ACh). The ACh crosses a tiny gap. Then it binds receptors, the docking spots on the muscle. Three diseases break that handshake, each at a different point. That is why one causes floppy paralysis, one causes rigid spasms, and one causes weakness. Click each one.

The neuromuscular junction

The nerve ending sits on top and the muscle below. Watch which part breaks: the ACh release, the brake, or the receptors.
Pick one of the four states.
Pick a statenormal · botulism · tetanus · MG

What is broken

Compare the three: Botulism blocks ACh release, so you get floppy (flaccid), descending paralysis that starts at the head and moves down. Tetanus blocks the inhibitory "brake" in the CNS, so you get rigid spasms and lockjaw. Myasthenia gravis destroys ACh receptors, so you get fatigable weakness. It gets worse with use and better with rest.