Biomaterial Database

Retinal fine structure in the European eel Anguilla anguilla. IV. Photoreceptors of the yellow eel stage. 1985

C R Braekevelt

The complex life cycle of the European eel (Anguilla anguilla) involves a long catadromous migration during which the eye undergoes a number of morphological alterations. This report deals with the fine structure of the photoreceptors of the yellow eel stage and is part of a comparative study of the retina of the eel during the major stages of its life cycle. The photoreceptors of the yellow eel are easily divisible into rods and single cones and the rods at least appear to be capable of retinomotor responses. Rods are more elongated and more numerous than cones. In the light-adapted state the inner segment of rods is of the same diameter as the outer segment but narrows abruptly in the myoid region. Cone inner segments on the other hand are much wider than the outer segments which taper distally. Both rods and cones display organelles in the inner segment indicative of high metabolic activity. Cone nuclei are located scleral to the external limiting membrane while rod nuclei are vitreal to this boundary. Both rods and cones display both invaginated and superficial synaptic sites. Except for an apparent increase in number and outer segment width of the rods, the photoreceptors of the yellow eel have changed only slightly from that described for the glass eel stage.

UI	MeSH Term	Description	Entries
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D009940	Organoids	An organization of cells into an organ-like structure. Organoids can be generated in culture, e.g., self-organized three-dimensional tissue structures derived from STEM CELLS (see MICROPHYSIOLOGICAL SYSTEMS). They are also found in certain NEOPLASMS.	Organoid
D010786	Photoreceptor Cells	Specialized cells that detect and transduce light. They are classified into two types based on their light reception structure, the ciliary photoreceptors and the rhabdomeric photoreceptors with MICROVILLI. Ciliary photoreceptor cells use OPSINS that activate a PHOSPHODIESTERASE phosphodiesterase cascade. Rhabdomeric photoreceptor cells use opsins that activate a PHOSPHOLIPASE C cascade.	Ciliary Photoreceptor Cells,Ciliary Photoreceptors,Rhabdomeric Photoreceptor Cells,Rhabdomeric Photoreceptors,Cell, Ciliary Photoreceptor,Cell, Photoreceptor,Cell, Rhabdomeric Photoreceptor,Cells, Ciliary Photoreceptor,Cells, Photoreceptor,Cells, Rhabdomeric Photoreceptor,Ciliary Photoreceptor,Ciliary Photoreceptor Cell,Photoreceptor Cell,Photoreceptor Cell, Ciliary,Photoreceptor Cell, Rhabdomeric,Photoreceptor Cells, Ciliary,Photoreceptor Cells, Rhabdomeric,Photoreceptor, Ciliary,Photoreceptor, Rhabdomeric,Photoreceptors, Ciliary,Photoreceptors, Rhabdomeric,Rhabdomeric Photoreceptor,Rhabdomeric Photoreceptor Cell
D012160	Retina	The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.	Ora Serrata
D000367	Age Factors	Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.	Age Reporting,Age Factor,Factor, Age,Factors, Age
D000811	Anguilla	A genus in the Family Anguillidae, Order Anguilliformes, that includes fresh water eels.	Anguillas
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia