The fine structure of prostomial photoreceptors in Eulalia viridis (Polychaeta; Annelida)
| ISSN: |
1432-0878
|
|---|---|
| Keywords: |
Photoreceptors ; Polychaete ; Submicrovillar cisternae ; Fine structure
|
| Source: |
Springer Online Journal Archives 1860-2000
|
| Topics: |
Biology
Medicine
|
| Notes: |
Summary The prostomium of Eulalia viridis has both microvillar and ciliary photoreceptors. The compound eyes each consist of a central lens surrounded by a layer of sensory and pigment cells. They resemble those of nereids, except that the lens is composed of vesiculated droplets produced by a specialized lenticular cell located in the cell layer surrounding the lens. Photoreceptoral microvilli of the sensory cell outer segments are underlain by “submicrovillar cisternae” (or SMC). The axial filament is ensheathed by part of the SMC complex. The sensory cells of the posterior photoreceptors are similar in cytology to those of the compound eyes but are not organized into “eyes”. Each ciliary photoreceptor unit consists of an extracellular vacuole bounded by a supporting cell and the ciliated terminal of a sensory cell dendrite which projects into the vacuole. They are similar to the ciliary photoreceptors of nereids. The discussion seeks to establish SMC as an important component of microvillar photoreceptors in polychaetes. SMC resemble subrhabdomeric cisternae of arthropod eyes and also lamellate structures found in photoreceptors of other animals. SMC are probably involved with the metabolism of photopigment.
|
| Type of Medium: |
Electronic Resource
|
| URL: |