. A laboratory manual and text-book of embryology. Embryology. THE BRAIN 349 occipital and parietal lobes (Fig. 33S); (3) the calcarinc fissure which includes between it and the parieto-occipital fissure the cuneus and marks the position of the visual area of the cerebrum; (4) the collateral fissure on the ventral surface of the temporal lobe, which produces the inward bulging on the floor of the posterior horn of the ventricle known as the collateral eminence. The calcarine fissure also affects the internal wall of the ventricle, causing the convexity termed the calcar avis. Simultaneously wi
. A laboratory manual and text-book of embryology. Embryology. THE BRAIN 349 occipital and parietal lobes (Fig. 33S); (3) the calcarinc fissure which includes between it and the parieto-occipital fissure the cuneus and marks the position of the visual area of the cerebrum; (4) the collateral fissure on the ventral surface of the temporal lobe, which produces the inward bulging on the floor of the posterior horn of the ventricle known as the collateral eminence. The calcarine fissure also affects the internal wall of the ventricle, causing the convexity termed the calcar avis. Simultaneously with the development of the collateral fissure appear other shallower depressions known as sulci. These have a definite arrangement and Gyrus cinguli Corp. callosum Siilc. Corp. callosi Spknium Parieto-occipital fissure Space of septum pellu- cidum Rostral lamina Parol- factory area. Cuneus Fig. Olfactory lobe Fissura rhinica Optic nerve Temporal lobe -Median surface of the right cerebral hemisphere from a seven months' fetus (Kollmann). with the fissures mark off from each other the various functional areas of the cere- brum. The surface convolutions between the depressions constitute the gyri and lobules of the adult cerebrum. Histogenesis of the Cerebral Cortex.—The three primitive zones typical of the neural tube are differentiated in the wall of the pallium: the ependymal, mantle and marginal layers. During the first two months the cortex remains thin and differentiation is slow. At eight weeks neuroblasts migrate from the ependymal and mantle zones into the marginal zone and give rise to layers of pyramidal cells typical of the cerebrum. The differentiation of these layers is most active during the third and fourth months. From the fourth month on the. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original wor
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectembryology, bookyear1
