Neupsy Key

Each muscle fiber is also surrounded by a basal lamina, or basement membrane. Lying under the basement membrane are specialized cells referred to as satellite cells. Satellite cells are derived…

CMSs are caused by defects affecting the presynaptic, synaptic basal lamina–associated, and postsynaptic regions of the neuromuscular junction. Inheritance is autosomal recessive, except in the dominantly inherited slow-channel CMS. While…

Approximately 50% of LEMS patients have a small cell lung cancer (SCLC), often not clinically evident at the inception of neuromuscular symptoms. Presumably, the immune response leading to LEMS begins…

Early in the disease course, a presumptive diagnosis of myasthenia gravis is supported by a test dose of edrophonium chloride (Tensilon), an acetylcholinesterase inhibitor characterized by very rapid onset (30-45…

The thymus gland plays a central role in the development of AChR-antibody MG, particularly for early-onset cases of MG (e.g., patients younger than 50 years). Hyperplastic thymus glands of patients…

Myasthenia gravis is seen in all age groups, with a bimodal distribution, affecting younger adults in their 20s and 30s (with a female predominance) and older adults in their 60s…

This technique is performed to specifically stress the safety factor by rapidly mobilizing and releasing multiple stores of ACh. With a 2-to 5-Hz RMNS, fewer stores of ACh are released,…

The nicotinic AChR contains five subunits arranged radially around a transmembrane ion channel. Antibodies generated in myasthenia gravis are primarily directed against the AChR alpha subunit. These antibodies may bind…

Alpha bungarotoxin has another use. Because it binds to tightly to the AChR, it provides a means of seeing each muscle fiber’s postsynaptic site. This is accomplished by tagging bungarotoxin…

The structure of the neuromuscular junction explains why it is so powerful. An axonal branch terminates in a branched structure that is laden with mitochondria, synaptic vesicles, and a number…