In this article we will discuss about the meaning and myesthenia gravis disease of neuromuscular junction.
Meaning of Neuromuscular Junction:
Neuromuscular junction (Fig. 2.14) is a functional junction between a nerve fiber and a muscle fiber. As the motor nerve approaches this junction, it loses the myelin sheath and the bare nerve expands. This expansion is known as the sole foot region or axon telodendria or terminal boutons.
The corresponding portion on the muscle membrane is the end plate region, which is thrown into a number of folds. These folds will have the receptor sites for acetylcholine (Fig. 2.15). The folds increase the surface area available for the action of acetylcholine.
Disease of Neuromuscular Junction—Myesthenia Gravis:
i. It is an autoimmune disease.
ii. Antibodies are produced against the ACh receptors present on the post-junction membrane.
iii. So the receptors get destroyed.
iv. ACh liberated during neuromuscular transmission fails to find adequate number of receptors for its action.
v. The amplitude of end plate potential is minimized.
vi. This leads to no development of action potential in the muscle.
vii. Features are easy fatigability, weakness.
viii. If the condition is severe, it can lead to respiratory paralysis and death.
ix. Treatment will be administration of anticholinesterase to prolong the action of acetylcholine.
Some of the other ways of treatment are:
a. Thymectomy to reduce antibody production
b. Administration of immunosuppressants to minimize the production of antibody.