A fundamental link between the nervous system and the muscular system.
The motor unit is made up of a motoneuron, located in the spinal cord, and all the muscle fibres it controls. When an electrical signal is emitted from the motoneuron, all the fibres in this unit contract simultaneously. It is this organization that allows the brain to transform an intention to move into concrete action.
A mechanism adapted to precision or force
Not all motor units are identical. Some control only a few muscle fibres, such as in the muscles of the eyes or fingers, allowing for extremely precise gestures. Others, however, can mobilize several hundred fibres, particularly in the leg muscles, to generate powerful movements such as running or jumping. This diversity offers a subtle balance between finesse and strength.
The Importance of Motor Units in Health
The proper functioning of motor units is essential for our daily movements. Neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS), affect motor neurons and progressively compromise the brain's ability to activate muscles. The study of motor units is therefore crucial to better understand, diagnose and treat these pathologies.
Other Words That May Be of Interest to You
- Motor neuron :
- Motor neurons involved in the transmission of motor information from the brain to the spinal cord and peripheral organs.