Search results
Results From The WOW.Com Content Network
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 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.
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]
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]
The pineal body also has photoreceptive cells which, though regressed, retain visual pigment like the photoreceptive cells of the regressed eye. The pineal gland in Proteus probably possesses some control over the physiological processes. [21] Behavioral experiments revealed that the skin itself is also sensitive to light. [22]
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]
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]
A gland is a cell or an organ in an animal's body that produces and secretes different substances that the organism needs, either into the bloodstream or into a body cavity or outer surface. [1] A gland may also function to remove unwanted substances such as urine from the body. [2] There are two types of gland, each with a different method of ...