Motor Disorders

Question 0

Signs of schwann cell lesions

Answer 0

Nerve conduction slowing or conduction block.

Ex. Guillain-Barre, Diphteria

Question 1

Signs of lesion of nerve soma

Answer 1

Muscle weakness and atrophy
Fibrillations and fasciculations
Eventual replacement of muscle fibers with connective tissue.

Ex. ALS (Lou Gehrig’s Disease) and Polio

Question 2

Lambert-Eaton Syndrome

Answer 2

Autoimmune disease, where circulating antibodies are directed against voltage-gated Ca2+ channels inmotor neuron terminals.

Results in muscle weakness due to reduced Ach release.

strength increases with sustained or repeated muscular contraction in otherwise weakened patients.

Associated with Oat cell carcinoma

Question 3

Slow Channel Syndrome

Answer 3

ACh binding to nAChRs causes prolonged opening of ACh receptor channels and, consequently, depolarization block

Question 4

Myotonia congenita (Chloride Channel Syndrome)

Answer 4

Myotonia congenita is a genetic disease in which fewer chloride channels are expressed.
The consequence is slow muscular relaxation. Patients suffer from muscle stiffness and hypertrophy.

Question 5

nAChRs in Denervated Muscle

Answer 5

Following denervation, nAChRs return to a supersensitive embryonic state (scattered across the surface of the muscle), with an adult state (converging to form NMJ) re-emerging with reinnervation.