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Pineal
The pineal gland, conarium, or epiphysis cerebri, is a small endocrine gland in the brain of most vertebrates. The pineal gland produces melatonin, a serotonin-derived hormone which modulates sleep patterns in both circadian and seasonal cycles. The shape of the gland resembles a pine cone, which gives it its name. The pineal gland is located in the epithalamus, near the center of the brain, between the two hemispheres, tucked in a groove where the two halves of the thalamus join. The pineal gland is one of the neuroendocrine secretory circumventricular organs in which capillaries are mostly permeable to solutes in the blood. Nearly all vertebrate species possess a pineal gland. The most important exception is a primitive vertebrate, the hagfish. Even in the hagfish, however, there may be a "pineal equivalent" structure in the dorsal diencephalon. The lancelet ''Branchiostoma lanceolatum'', an early chordate which is a close relative to vertebrates, also lacks a recognizab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parietal Eye
A parietal eye, also known as a third eye or pineal eye, is a part of the epithalamus present in some vertebrates. The eye is located at the top of the head, is photoreceptive and is associated with the pineal gland, regulating circadian rhythmicity and hormone production for thermoregulation. The hole in the head which contains the eye is known as a pineal foramen or parietal foramen, since it is often enclosed by the parietal bones. Presence in various animals The parietal eye is found in the tuatara, most lizards, frogs, salamanders, certain bony fish, sharks, and lampreys. It is absent in mammals, but was present in their closest extinct relatives, the therapsids, suggesting it was lost during the course of the mammalian evolution due to it being useless in endothermic animals. It is also absent in the ancestrally endothermic ("warm-blooded") archosaurs such as birds. The parietal eye is also lost in ectothermic ("cold-blooded") archosaurs like crocodilians, and in turtl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Melatonin
Melatonin is a natural product found in plants and animals. It is primarily known in animals as a hormone released by the pineal gland in the brain at night, and has long been associated with control of the sleep–wake cycle. In vertebrates, melatonin is involved in synchronizing circadian rhythms, including sleep–wake timing and blood pressure regulation, and in control of seasonal rhythmicity including reproduction, fattening, moulting and hibernation. Many of its effects are through activation of the melatonin receptors, while others are due to its role as an antioxidant. In plants, it functions to defend against oxidative stress. It is also present in various foods. Melatonin was discovered in 1958. In addition to its role as a natural hormone, melatonin is used as a dietary supplement and medication in the treatment of sleep disorders such as insomnia and circadian rhythm sleep disorders; for information on melatonin as a supplement and medication, see the mel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circumventricular Organs
Circumventricular organs (CVOs) ( circum-: around ; ventricular: of ventricle) are structures in the brain characterized by their extensive and highly permeable capillaries, unlike those in the rest of the brain where there exists a blood–brain barrier (BBB) at the capillary level. Although the term "circumventricular organs" was originally proposed in 1958 by Austrian anatomist Helmut O. Hofer concerning structures around the brain ventricular system, the penetration of blood-borne dyes into small specific CVO regions was discovered in the early 20th century. The ''permeable'' CVOs enabling rapid neurohumoral exchange include the subfornical organ (SFO), the area postrema (AP), the vascular organ of lamina terminalis (VOLT — also known as the ''organum vasculosum of the lamina terminalis'' (OVLT)), the median eminence, the pituitary neural lobe, and the pineal gland. The circumventricular organs are midline structures around the third and fourth ventricles that a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epithalamus
The epithalamus is a posterior (dorsal) segment of the diencephalon. The epithalamus includes the habenular nuclei and their interconnecting fibers, the habenular commissure, the stria medullaris and the pineal gland. Functions The function of the epithalamus is to connect the limbic system to other parts of the brain. The epithalamus also serves as a connecting point for the dorsal diencephalic conduction system, which is responsible for carrying information from the limbic forebrain to limbic midbrain structures. Some functions of its components include the secretion of melatonin and secretion of hormones from the pituitary gland (by the pineal gland circadian rhythms), regulation of motor pathways and emotions, and how energy is conserved in the body. A study has shown that the lateral habenula, an epithalamic structure, produces spontaneous theta oscillatory activity that was correlated with theta oscillation in the hippocampus. The same study also found that the increase ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circadian Rhythm
A circadian rhythm (), or circadian cycle, is a natural, internal process that regulates the sleep–wake cycle and repeats roughly every 24 hours. It can refer to any process that originates within an organism (i.e., endogenous) and responds to the environment ( entrained by the environment). These 24-hour rhythms are driven by a circadian clock, and they have been widely observed in animals, plants, fungi and cyanobacteria. The term ''circadian'' comes from the Latin '' circa'', meaning "approximately", and ''dies'', meaning "day". Processes with 24-hour cycles are more generally called diurnal rhythms; diurnal rhythms should not be called circadian rhythms unless they can be confirmed as endogenous, and not environmental. Although circadian rhythms are endogenous, they are adjusted to the local environment by external cues called zeitgebers (German for "time givers"), which include light, temperature and redox cycles. In clinical settings, an abnormal circadian rhythm in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
René Descartes
René Descartes ( or ; ; Latinized: Renatus Cartesius; 31 March 1596 – 11 February 1650) was a French philosopher, scientist, and mathematician, widely considered a seminal figure in the emergence of modern philosophy and science. Mathematics was central to his method of inquiry, and he connected the previously separate fields of geometry and algebra into analytic geometry. Descartes spent much of his working life in the Dutch Republic, initially serving the Dutch States Army, later becoming a central intellectual of the Dutch Golden Age. Although he served a Protestant state and was later counted as a deist by critics, Descartes considered himself a devout Catholic. Many elements of Descartes' philosophy have precedents in late Aristotelianism, the revived Stoicism of the 16th century, or in earlier philosophers like Augustine. In his natural philosophy, he differed from the schools on two major points: first, he rejected the splitting of corporeal substance i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lamprey
Lampreys (sometimes inaccurately called lamprey eels) are an ancient extant lineage of jawless fish of the order Petromyzontiformes , placed in the superclass Cyclostomata. The adult lamprey may be characterized by a toothed, funnel-like sucking mouth. The common name "lamprey" is probably derived from Latin , which may mean "stone licker" ( "to lick" + "stone"), though the etymology is uncertain. ''Lamprey'' is sometimes seen for the plural form. There are about 38 known extant species of lampreys and five known extinct species. Parasitic carnivorous species are the most well-known, and feed by boring into the flesh of other fish to suck their blood; but only 18 species of lampreys engage in this micropredatory lifestyle. Of the 18 carnivorous species, nine migrate from saltwater to freshwater to breed (some of them also have freshwater populations), and nine live exclusively in freshwater. All non-carnivorous forms are freshwater species. Adults of the non-carnivorous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pine Cone
A conifer cone (in formal botanical usage: strobilus, plural strobili) is a seed-bearing organ on gymnosperm plants. It is usually woody, ovoid to globular, including scales and bracts arranged around a central axis, especially in conifers and cycads. The cone of Pinophyta (conifer clade) contains the reproductive structures. The woody cone is the female cone, which produces seeds. The male cone, which produces pollen, is usually herbaceous and much less conspicuous even at full maturity. The name "cone" derives from Greek ''konos'' (pine cone), which also gave name to the geometric cone. The individual plates of a cone are known as ''scales''. The ''umbo'' of a conifer cone refers to the first year's growth of a seed scale on the cone, showing up as a protuberance at the end of the two-year-old scale. The male cone (microstrobilus or pollen cone) is structurally similar across all conifers, differing only in small ways (mostly in scale arrangement) from species to species ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cistern Of Great Cerebral Vein
The superior cistern (cistern of great cerebral vein, quadrigeminal cistern, Bichat's canal) is a dilation as a subarachnoid cistern of the subarachnoid space around the brain. It lies between the splenium of the corpus callosum and the superior surface of the cerebellum. It extends between the layers of the tela choroidea of the third ventricle. It contains the great cerebral vein, posterior cerebral artery, quadrigeminal artery, glossopharyngeal nerve (CN IX), and the pineal gland. Structure The superior cistern is a dilatation as a subarachnoid cistern of the subarachnoid space around the brain. It lies between the splenium of the corpus callosum (superiorly), the cerebellar vermis (inferiorly and posteriorly), and the tentorial margin. It lies medial to part of the medial occipital cortex. It extends between the layers of the tela choroidea of the third ventricle. Contents The superior cistern contains a number of important structures, including: * the great cerebral ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sleep
Sleep is a sedentary state of mind and body. It is characterized by altered consciousness, relatively inhibited Perception, sensory activity, reduced muscle activity and reduced interactions with surroundings. It is distinguished from wakefulness by a decreased ability to react to stimulus (physiology), stimuli, but more reactive than a coma or disorders of consciousness, with sleep displaying different, active brain patterns. Sleep occurs in sleep cycle, repeating periods, in which the body alternates between two distinct modes: REM sleep and non-rapid eye movement sleep, non-REM sleep. Although REM stands for "rapid eye movement", this mode of sleep has many other aspects, including virtual paralysis of the body. dream, Dreams are a succession of images, ideas, emotions, and sensations that usually occur involuntarily in the mind during certain stages of sleep. During sleep, most of the human body, body's systems are in an anabolic state, helping to restore the Immunity (medi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conifer Cone
A conifer cone (in formal botanical usage: strobilus, plural strobili) is a seed-bearing organ on gymnosperm plants. It is usually woody, ovoid to globular, including scales and bracts arranged around a central axis, especially in conifers and cycads. The cone of Pinophyta (conifer clade) contains the reproductive structures. The woody cone is the female cone, which produces seeds. The male cone, which produces pollen, is usually herbaceous and much less conspicuous even at full maturity. The name "cone" derives from Greek ''konos'' (pine cone), which also gave name to the geometric cone. The individual plates of a cone are known as ''scales''. The ''umbo'' of a conifer cone refers to the first year's growth of a seed scale on the cone, showing up as a protuberance at the end of the two-year-old scale. The male cone (microstrobilus or pollen cone) is structurally similar across all conifers, differing only in small ways (mostly in scale arrangement) from species to species ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brain
The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head ( cephalization), usually near organs for special senses such as vision, hearing and olfaction. Being the most specialized organ, it is responsible for receiving information from the sensory nervous system, processing those information (thought, cognition, and intelligence) and the coordination of motor control (muscle activity and endocrine system). While invertebrate brains arise from paired segmental ganglia (each of which is only responsible for the respective body segment) of the ventral nerve cord, vertebrate brains develop axially from the midline dorsal nerve cord as a vesicular enlargement at the rostral end of the neural tube, with centralized control over all body segments. All vertebrate brains can be embryonically divided into three parts: the forebrain (prosencep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
