Of or pertaining to James the First, of England, or of his reign or times; especially, pertaining to a style of architecture and decoration popular in the time of James I.; as, Jacobean writers. Etymology: From L. Jacobus James.
ALS is a progressive, degenerative disease of the nervous system. It is one of a group of diseases, called motor neuron diseases (MND), in which specialized nerve cells that control movement of the voluntary muscles gradually cease functioning and die. Fasciculation is a sign of muscle irritability, as the normal action of the lower motor neuron on the muscle is impaired. 2  The sole involvement of lower motor neurons can be seen in a form of ALS called progressive muscular atrophy.
Spinal muscular atrophy (SMA) refers to a group of. inherited diseases of the motor nerves that cause. muscle weakness and atrophy (wasting). The motor. nerves arise from the spinal cord and control the. muscles that are used for activities such as breathing, crawling, walking, head and neck control, and swallowing.