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Ultradian
In chronobiology, an ultradian rhythm is a recurrent period or cycle repeated throughout a 24-hour day. In contrast, circadian rhythms complete one cycle daily, while infradian rhythms such as the menstrual cycle have periods longer than a day. The ''Oxford English Dictionary's'' definition of ''Ultradian'' specifies that it refers to cycles with a period shorter than a day but longer than an hour. The descriptive term ultradian is used in sleep research in reference to the 90–120 minute cycling of the sleep stages during human sleep. There is a circasemidian rhythm in body temperature and cognitive function which is technically ultradian. However, this appears to be the first harmonic of the circadian rhythm of each and not an endogenous rhythm with its own rhythm generator. Other ultradian rhythms include blood circulation, blinking, pulse, hormonal secretions such as growth hormone, heart rate, thermoregulation, micturition, bowel activity, nostril dilation, appetite, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infradian
In chronobiology, an infradian rhythm is a rhythm with a period longer than the period of a circadian rhythm, i.e., one cycle is longer than 24 hours. Some examples of infradian rhythms in mammals include menstrual cycle, menstruation, Sexual reproduction, breeding, Migration (ecology), migration, hibernation, molting and fur or Human hair growth#Growth cycle, hair growth, and tidal or seasonal rhythms. In contrast, ultradian rhythms have periods shorter (<24 hours) than the period of a circadian rhythm. Several infradian rhythms are known to be caused by hormone or neurotransmitter stimulation or by environmental factors such as the lunar cycles. For example, seasonal depression, an example of an infradian rhythm occurring once a year, can be caused by the systematic lowering of light levels during the winter. The seasonal affective disorder can be classified as infradian, or as circannual, which means occurring on a yearly basis. Carrie Arnold [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sleep Cycle
The sleep cycle is an oscillation between the slow-wave and REM (paradoxical) phases of sleep. It is sometimes called the ultradian sleep cycle, sleep–dream cycle, or REM-NREM cycle, to distinguish it from the circadian alternation between sleep and wakefulness. In humans, this cycle takes 70 to 110 minutes (90 ± 20 minutes). Within the sleep of adults and infants there are cyclic fluctuations between quiet and active sleep. These fluctuations may persist during wakefulness as rest-activity cycles but are less easily discerned. Characteristics Electroencephalography shows the timing of sleep cycles by virtue of the marked distinction in brainwaves manifested during REM and non-REM sleep. Delta wave activity, correlating with slow-wave (deep) sleep, in particular shows regular oscillations throughout a good night's sleep. Secretions of various hormones, including renin, growth hormone, and prolactin, correlate positively with delta-wave activity, while secretion of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bipolar Disorder
Bipolar disorder (BD), previously known as manic depression, is a mental disorder characterized by periods of Depression (mood), depression and periods of abnormally elevated Mood (psychology), mood that each last from days to weeks, and in some cases months. If the elevated mood is severe or associated with psychosis, it is called ''mania''; if it is less severe and does not significantly affect functioning, it is called ''hypomania''. During mania, an individual behaves or feels abnormally energetic, happy, or irritable, and they often make impulsive decisions with little regard for the consequences. There is usually, but not always, a Sleep deprivation, reduced need for sleep during manic phases. During periods of depression, the individual may experience crying, have a negative outlook on life, and demonstrate poor eye contact with others. The risk of suicide is high. Over a period of 20 years, 6% of those with bipolar disorder died by suicide, with about one-third Suicide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circadian Rhythm
A circadian rhythm (), or circadian cycle, is a natural oscillation that repeats roughly every 24 hours. Circadian rhythms can refer to any process that originates within an organism (i.e., Endogeny (biology), endogenous) and responds to the environment (is Entrainment (chronobiology), entrained by the environment). Circadian rhythms are regulated by a circadian clock whose primary function is to rhythmically co-ordinate biological processes so they occur at the correct time to maximize the fitness of an individual. Circadian rhythms have been widely observed in animals, plants, fungi and cyanobacteria and there is evidence that they evolved independently in each of these kingdoms of life. The term ''circadian'' comes from the Latin ', meaning "around", and ', 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 ci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circasemidian Rhythm
In chronobiology, a circasemidian rhythm is a physiological arousal cycle that peaks twice in a 24-hour day. It may also be called the semicircadian rhythm. Numerous studies have demonstrated that human circadian rhythms in many measures of performance and physiological activity have a 2-peak daily (circasemidian) pattern. The word, circasemidian, is based upon the Latin words ''circa'' ("about"), ''semi'' ("half") and ''dia'' ("day"). Thus, this is a rhythm that has two cycles per day, and some investigators have referred to it as the semicircadian rhythm. It usually serves to (1) deepen the pre-dawn nadir in body temperature and cognitive performance, (2) create a flat spot during the early afternoon in the daytime increase in body temperature and cognitive performance (the "post-lunch dip"), and (3) heighten the early-evening peak in body temperature and cognitive performance. Broughton was the first to bring this characteristic of human performance to the attention of researchers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nasal Cycle
The nasal cycle is the subconscious alternating partial Nasal congestion, congestion and decongestion of the nasal cavity, nasal cavities in humans and other animals. This results in greater airflow through one nostril with periodic alternation between the nostrils. It is a physiological congestion of the nasal conchae, also called the nasal turbinates (curled bony projections within the nasal cavities), due to selective activation of one half of the autonomic nervous system by the hypothalamus. It should not be confused with pathological nasal congestion. Description In the modern western literature, it was first described by the German physician Richard Kayser in 1895. In 1927, Heetderks described the alternating turgescence of the inferior turbinates in 80% of a normal population. According to Heetderks, the cycle is the result of alternating congestion and decongestion of the nasal conchae or turbinates, predominantly the inferior turbinates, which are by far the largest o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leptin Circadian Cycle (24 Hours)
Leptin (from Ancient Greek, Greek λεπτός ''leptos'', "thin" or "light" or "small"), also known as obese protein, is a protein hormone predominantly made by adipocytes (cells of adipose tissue). Its primary role is likely to regulate long-term Energy homeostasis, energy balance. As one of the major signals of energy status, leptin levels influence appetite, Hunger (physiology), satiety, and motivated behaviors oriented toward the maintenance of energy reserves (e.g., feeding, foraging behaviors). The amount of circulating leptin correlates with the amount of energy reserves, mainly Triglyceride, triglycerides stored in adipose tissue. High leptin levels are interpreted by the brain that energy reserves are high, whereas low leptin levels indicate that energy reserves are low, in the process adapting the organism to Starvation response, starvation through a variety of metabolic, endocrine, neurobiochemical, and behavioral changes. Leptin is coded for by the ''LEP'' gene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bowel
The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The tract is the largest of the body's systems, after the cardiovascular system. The GI tract contains all the major organs of the digestive system, in humans and other animals, including the esophagus, stomach, and intestines. Food taken in through the mouth is digested to extract nutrients and absorb energy, and the waste expelled at the anus as feces. ''Gastrointestinal'' is an adjective meaning of or pertaining to the stomach and intestines. Most animals have a "through-gut" or complete digestive tract. Exceptions are more primitive ones: sponges have small pores ( ostia) throughout their body for digestion and a larger dorsal pore ( osculum) for excretion, comb jellies have both a ventral mouth and dorsal anal pores, while cnidarians and acoels have a single pore for both digestion and excretion. The human gast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chronobiology
Chronobiology is a field of biology that examines timing processes, including periodic (cyclic) phenomena in living organisms, such as their adaptation to solar- and lunar-related rhythms. These cycles are known as biological rhythms. Chronobiology comes from the ancient Greek χρόνος (''chrónos'', meaning "time"), and biology, which pertains to the study, or science, of life. The related terms ''chronomics'' and ''chronome'' have been used in some cases to describe either the molecular mechanisms involved in chronobiological phenomena or the more quantitative aspects of chronobiology, particularly where comparison of cycles between organisms is required. Chronobiological studies include but are not limited to comparative anatomy, physiology, genetics, molecular biology and behavior of organisms related to their biological rhythms. Other aspects include epigenetics, development, reproduction, ecology and evolution. The subject Chronobiology studies variations of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
