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The structure of the pineal organ of the bluefin tuna, Thunnus thynnus
Author(s) -
Murphy Richard C.
Publication year - 1971
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/jmor.1051330102
Subject(s) - biology , diencephalon , anatomy , golgi apparatus , thunnus , central nervous system , tuna , microbiology and biotechnology , neuroscience , fish <actinopterygii> , endoplasmic reticulum , fishery
The pineal organ of the bluefin tuna was studied using light and electron microscopy. The pineal, an evagination in the diencephalic pallium, consists of a distal expanded end‐organ and a stalk. A pineal nerve connects this end‐organ to the habenular area of the diencephalon. The tissues above the pineal are modified for light transmission. Supporting cells are the most numerous type seen in the pineal tissue. The cytoplasm often contains glycogen, while the golgi apparatus is seldom seen. The plasma membrane is a complex of folded membranes interdigitating with adjacent cells. The sensory cells are characterized by a basal nucleus, a constricted neck region, and an ellipsoid region that is capped distally by lamellae. Sensory cells have the basic appearance of retinal photoreceptors. The lamellae are more disorganized than those of retinal rods, and some lamellae appear to be discharged from the cell. This study indicates that the pineal may function to deliver photoperiodic stimuli to the central nervous system, through the transmission of nerve impulses.