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The pineal gland is present in almost all vertebrates, but is absent in protochordates in which there is a simple pineal homologue. The hagfish , archaic vertebrates, lack a pineal gland. [ 7 ] In some species of amphibians and reptiles, the gland is linked to a light-sensing organ, variously called the parietal eye , the pineal eye or the ...
The pineal gland, a photosensitive organ regulating melatonin production by capturing light signals through the photoreceptor cell converting them into intercellular signals of the lamprey is located in the midline of its body, for lamprey, the pineal eye is accompanied by the parapineal organ. [38]
The eye is at the top of the head; is photoreceptive; and is associated with the pineal gland, which regulates circadian rhythmicity and hormone production for thermoregulation. [1] The hole that contains the eye is known as the pineal foramen or parietal foramen, because it is often enclosed by the parietal bones.
Usually, this animal is simply called the iguana. The green iguana ranges over a large geographic area; it is native from southern Brazil and Paraguay as far north as Mexico. A herbivore, it has adapted significantly with regard to locomotion and osmoregulation as a result of its diet. It grows to 1.7 m (5.6 ft) in length from head to tail ...
It is part of the pineal complex, another part of which is the pineal gland, which in tuatara secretes melatonin at night. [24] Some salamanders have been shown to use their pineal bodies to perceive polarised light, and thus determine the position of the sun, even under cloud cover, aiding navigation. [66]
The first Pineal Opsin (Pinopsin) was found in the chicken pineal gland. It is a blue sensitive opsin (λ max = 470 nm). [76] [77] Pineal opsins have a wide range of expression in the brain, most notably in the pineal region.
Castoreum. Castoreum / k æ s ˈ t ɔːr i ə m / is a yellowish exudate from the castor sacs of mature beavers used in combination with urine to scent mark their territory. [1] [2]Both beaver sexes have a pair of castor sacs and a pair of anal glands, located in two cavities under the skin between the pelvis and the base of the tail. [3]
In some cases, "blind" cavefish may still be able to see: Juvenile Mexican tetras of the cave form are able to sense light via certain cells in the pineal gland , [20] and Congo blind barbs are photophobic, despite only having retinas and optical nerves that are rudimentary and located deep inside the head, and completely lacking a lens. [21]