| Name: | primary motor neuron |
|---|---|
| Synonyms: | primary motoneuron |
| Definition: | Motor neurons that arise during the first day of development. Primary motoneurons have larger diameter cell bodies and axons than secondary motoneurons and are positioned more dorsally and medially than secondary motoneurons. Primary motoneurons are present in a single bilateral pair of clusters in each spinal segment and innervate axial muscle fibers in the corresponding pair of myotomes. Axons make a conspicuous loop around the Mauthner axon before entering the ventral root. |
| Ontology: | Anatomy Ontology [ZFA:0009244] |
| Name: | axon |
|---|---|
| Synonyms: | |
| Definition: | The long process of a neuron that conducts nerve impulses, usually away from the cell body to the terminals and varicosities, which are sites of storage and release of neurotransmitter. |
| Ontology: | GO: Cellular Component [GO:0030424] QuickGO AmiGO |
| Name: | morphology |
|---|---|
| Synonyms: | |
| Definition: | A quality of a single physical entity inhering in the bearer by virtue of the bearer's size or shape or structure. |
| Ontology: | Phenotypic Quality Ontology [PATO:0000051] |