8. UROPHYSIS AND CAUDAL NEUROSECRETORY SYSTEM
403
Fig. 3. Electron micrograph of Gillichthys urophysial capillary (CAP) to show
surrounding axon profiles containing elementary neurosecretory granules. Insert at
right is higher magnification of one axon to show details of granules (in this species
more irregularly shaped than in others ). BM, basement membrane; EN, endothelium.
often of large size (in comparison with adjacent motor neurons) with
polymorphic nuclei, sometimes elaborately multilobate, and intensely
basophilic cytoplasm. Endocellular capillaries are occasionally evident.
From the cell soma, which possesses dendritic processes, one of which is
often directed toward or even into the central canal of the spinal cord,
proceeds a large, unmyelinated axon to terminate in association with
capillaries in the urophysis ( Figs. 1C and 3). Enlargements of these axons
403
Fig. 3. Electron micrograph of Gillichthys urophysial capillary (CAP) to show
surrounding axon profiles containing elementary neurosecretory granules. Insert at
right is higher magnification of one axon to show details of granules (in this species
more irregularly shaped than in others ). BM, basement membrane; EN, endothelium.
often of large size (in comparison with adjacent motor neurons) with
polymorphic nuclei, sometimes elaborately multilobate, and intensely
basophilic cytoplasm. Endocellular capillaries are occasionally evident.
From the cell soma, which possesses dendritic processes, one of which is
often directed toward or even into the central canal of the spinal cord,
proceeds a large, unmyelinated axon to terminate in association with
capillaries in the urophysis ( Figs. 1C and 3). Enlargements of these axons