Motorneuron

Motorneurons are nerve cells that form the primary pathway for signals from the central nervous system to the body's muscles, initiating movement. They are a crucial component of the motor system, which includes the brain, spinal cord, and the motor neurons themselves. These neurons originate in the central nervous system, either in the brainstem or the spinal cord, and extend their axons to innervate skeletal muscle fibers. When a motor neuron is activated, it releases neurotransmitters, such as acetylcholine, at the neuromuscular junction, triggering a muscle contraction.

There are two main types of motor neurons: upper motor neurons and lower motor neurons. Upper motor neurons are located in the cerebral cortex and brainstem and transmit signals down to lower motor neurons. Lower motor neurons are found in the spinal cord and brainstem and directly innervate the muscles. Damage to motor neurons, whether from injury or disease, can lead to muscle weakness, paralysis, and atrophy. Conditions like amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA) are examples of diseases that affect motor neurons. The proper functioning of motor neurons is essential for all voluntary and involuntary movements.