. Biology of the vertebrates : a comparative study of man and his animal allies. Vertebrates; Vertebrates -- Anatomy; Anatomy, Comparative. J2Q Biology of the Vertebrates Lemniscus Anterior Medulla these impulses as well as of coordination of muscular activity. In both of these tracts the primary sensory neurons are similar to those described for the fasciculi gracilis and cuneatus. Collaterals, leaving these neurons along their course, enter the dorsal gray matter to synapse with the neurons of the second order. The cell bodies of the dorsal spinocerebellar tract are located in the nucleus do
. Biology of the vertebrates : a comparative study of man and his animal allies. Vertebrates; Vertebrates -- Anatomy; Anatomy, Comparative. J2Q Biology of the Vertebrates Lemniscus Anterior Medulla these impulses as well as of coordination of muscular activity. In both of these tracts the primary sensory neurons are similar to those described for the fasciculi gracilis and cuneatus. Collaterals, leaving these neurons along their course, enter the dorsal gray matter to synapse with the neurons of the second order. The cell bodies of the dorsal spinocerebellar tract are located in the nucleus dorsalis (Clarke's col- umn) from which neurites run into the dorsal tract of the same side of the cord (Fig. 619). These fibers run forward through the medulla and enter the cerebellum by way of the restiform body (Fig. 644). The ventral spinocerebellar tracts are composed of neurites whose cell bodies are in the dorsal horns and adjacent portions of the gray matter. Some fibers enter the nearby tract of the same side of the cord; others cross over, through the ventral commissure, to run forward through the ventral tract of the opposite side. Each ventral spinocerebellar tract passes through the medulla and deeper part of the pons to enter the anterior cerebellar peduncle, through which it swings back into the anterior part of the cerebellum (Fig. 645). (d) Corticospinal Tracts.—Numerous motor pathways eventually leave the spinal cord through the primary motor neuron or ''final common path," as mentioned previously. Many groups of fibers exert involuntary control over the muscles, while several which descend from the cerebral cortex place the skeletal muscles under voluntary control. The most important voluntary tracts entering the spinal cord are the corticospinals which originate in giant pyramidal cells of the motor cortex, immediately anterior to the central sulcus. The neurites of these pyramidal cells pass successively through the white matter of the cerebral hemisp
Size: 1256px × 1988px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, booksubjectanatomycomparative, booksubjectverte
