. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. GASTROPOD MODEL OF LEAKXIXC 523. CELL IV CELL V FIGURE 15. Schematic representation of Hcnitisscnda eye showing the general configura- tion of the five photoreceptors (dark stipple), the rhabdomere (black) beneath the lens, and the course of axons which enter the optic nerve (black dot). Cell IV is situated above cell V, and their rhabdomeres are apposed (Stensaas ct al., 1969). photoreceptors within the same eye. Electron microscopic sections revealed a faint and a darkly stained cell. The axons of these two cells could the
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. GASTROPOD MODEL OF LEAKXIXC 523. CELL IV CELL V FIGURE 15. Schematic representation of Hcnitisscnda eye showing the general configura- tion of the five photoreceptors (dark stipple), the rhabdomere (black) beneath the lens, and the course of axons which enter the optic nerve (black dot). Cell IV is situated above cell V, and their rhabdomeres are apposed (Stensaas ct al., 1969). photoreceptors within the same eye. Electron microscopic sections revealed a faint and a darkly stained cell. The axons of these two cells could then be traced by thick and thin sections to sites of apposition between faint and darkly stained endings —' 30 from the optic nerves' entry point into the pleural ganglion (Fig. 14). These experiments, taken together, provide strong evidence that the photoreceptors synapse on each other at their terminal branchs within the pleural ganglion. Optic ganglion cells There are 14 cells in each optic ganglion (Stensaas ct al., 1969). The axons of these cells join those of the photoreceptors to form the optic nerve (10-20 /xm), which enters the lateral aspect of the pleural ganglion (Fig. 16). The axons of optic ganglion cells continue to course in a well-defined tract approximately 300 into the pleural ganglion. Optic ganglion cells (except for one, the largest) FIGURE 14A. (Numbered 7) Electron micrograph showing HRP-labeled photoreceptor soma (s) and cross-section of optic nerve. The pigment cells contain numerous pigment gran- ules (pg). The optic nerve consists of five axons (1-5) surrounded by a glial sheath (gs). A darkly labeled axon (a) corresponds to the labeled soma. A partially filled area indicated by arrow (bottom center) may be the result of some leakage from a previous unstable electrode penetration (Crow et al., 1979). A faintly stained axon, apparent in the optic nerve, was stained during this previous penetration. FIGURE 14B. (Numbered 8) Electron micrograph
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
