The anatomy of the nervous system, from the standpoint of development and function . ons form the innermost stratum of the retina, the stratum optician,through which they enter the optic nerve. It will be apparent from Fig. 160that the visual cells are the receptors and neurons of the first order in the opticpath. The impulses are transmitted through the bipolar cells to the ganglioncells, whose axons, in turn, carry them by way of the optic nerves to the supe-rior colliculus. lateral geniculate body, and pulvinar of the thalmus. In the samefigure it may be seen that the nerve also contains so
The anatomy of the nervous system, from the standpoint of development and function . ons form the innermost stratum of the retina, the stratum optician,through which they enter the optic nerve. It will be apparent from Fig. 160that the visual cells are the receptors and neurons of the first order in the opticpath. The impulses are transmitted through the bipolar cells to the ganglioncells, whose axons, in turn, carry them by way of the optic nerves to the supe-rior colliculus. lateral geniculate body, and pulvinar of the thalmus. In the samefigure it may be seen that the nerve also contains some efferent fibers whichterminate in the retina (Arey. 1916). The Optic Chiasma and Optic Tracts.—The optic nerve emerges from thebulbus oculi at the nasal side of the posterior pole and. after entering the craniumthrough the optic foramen, unites with its fellow of the opposite side to form the Pulvinar of thalamus Aqueduct of cerebrum Red nucleusMedial geniculate body. - — ?- y /Tegmentum Lateral geniculate body Cerebral peduncleOptic tract- Posterior perforated substance. Substantia nigra Base of peduncle Mammillary body or perforated substance Tuber cinereum Optic nerve Optic chiasma Olfactory trigonendibulum Fig. 161.—The connections and relations of the optic tracts. The mesencephalon has been cutacross and the specimen is viewed from below. (Sobotta-McMurrich . optic chiasma. in which a partial decussation of the fibers takes place ( 162). Beyond the decussation fibers from both retinae are continued ineach of the optic tracts. In the chiasma the fibers from the two optic nervesare so distributed that each tract receives the fibers from the lateral half of theretina of its own side and those from the medial half of the opposite optic tracts partially encircle the ends of the cerebral peduncles. Eachtract divides into a medial and a lateral root, of which the former goes to themedial geniculate body and does not consist of optic nerve-fibers. The
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectnervoussystem, bookye
