Early embryonic development of the camel lumbar spinal cord segment. (with 8 figures) [electronic resource]

Includes references.

The lumbar spinal Cord segment of the camel embryos at 2.4 to 28 cm CVRL was examined. Major changes are occurring in the organization of the lumbar spinal cord segment at this early developmental period. At the 2.4, 2.7 and 3.6 cm CVRL the three primary layers; ependymal, mantle and marginal cells layer in the developing lumbar spinal cord segment were demonstrated. The mantle layer is the first to show striking differentiation while the marginal layer is represented by thin outer rim. Proliferation and differentiation of the neuroepithelial cells in the developing spinal cord produce the thick lateral walls, thin roof and floor plates. The spinal ganglion and dorsal root of the spinal nerve are differentiated. At 2.7 cm CVRL differential thickening of the lateral walls produces shallow longitudinal groove called sulcus limitans which separates the dorsal part (alar plate) from the ventral part (basal plate). The ventral root of the spinal nerve and the spinal cord ganglion are embedded in loose mesenchyme which tends to differentiate into spinal meninges. At 3.6 cm CVRL the basal plate which is the future ventral gray horn is seen to be quite voluminous and the dorsal and ventral roots unite to form the beginning of the spinal nerve. At 5.5 cm CVRL the alar plates enlarge forming the dorsal septum. At 8.4 to 10.5 cm CVRL the basal plates enlarge, and bulge ventrally on each side of the midline producing the distinct ventral median fissure, the white and gray matters can be recognized. At 28 cm CVRL the lumen of the spinal cord is differentiated into the central canal bounded dorsally and ventrally by dorsal and ventral gray commissures therefore the gray-matter takes the appearance of butterfly. The lumbar spinal nerve and their roots are well distinct.The lumbar spinal Cord segment of the camel embryos at 2.4 to 28 cm CVRL was examined. Major changes are occurring in the organization of the lumbar spinal cord segment at this early developmental period. At the 2.4, 2.7 and 3.6 cm CVRL the three primary layers; ependymal, mantle and marginal cells layer in the developing lumbar spinal cord segment were demonstrated. The mantle layer is the first to show striking differentiation while the marginal layer is represented by thin outer rim. Proliferation and differentiation of the neuroepithelial cells in the developing spinal cord produce the thick lateral walls, thin roof and floor plates. The spinal ganglion and dorsal root of the spinal nerve are differentiated. At 2.7 cm CVRL differential thickening of the lateral walls produces shallow longitudinal groove called sulcus limitans which separates the dorsal part (alar plate) from the ventral part (basal plate). The ventral root of the spinal nerve and the spinal cord ganglion are embedded in loose mesenchyme which tends to differentiate into spinal meninges. At 3.6 cm CVRL the basal plate which is the future ventral gray horn is seen to be quite voluminous and the dorsal and ventral roots unite to form the beginning of the spinal nerve. At 5.5 cm CVRL the alar plates enlarge forming the dorsal septum. At 8.4 to 10.5 cm CVRL the basal plates enlarge, and bulge ventrally on each side of the midline producing the distinct ventral median fissure, the white and gray matters can be recognized. At 28 cm CVRL the lumen of the spinal cord is differentiated into the central canal bounded dorsally and ventrally by dorsal and ventral gray commissures therefore the gray-matter takes the appearance of butterfly. The lumbar spinal nerve and their roots are well distinct.

Summary in Arabic.