Circadian Rhythms
Stress messes with circadian rhythm
The Link Between Stress and Your Circadian Rhythm. Like many hormones, cortisol plays a variety of roles in the human body. When we are chronically stressed, it is released in higher amounts throughout the day. ... Cortisol also affects circadian genes in liver and adrenal cells.
Who won Nobel Prize in Physiology or Medicine for unveiling circadian rhythms?
2017 Nobel Prize Winner Michael W. Young
suprachiasmatic nucleus of the hypothalamus
Blood levels of the pineal hormone melatonin are high at night and low during the day. Its secretion is regulated by a rhythm-generating system located in the suprachiasmatic nucleus of the hypothalamus, which is in turn regulated by light.
SCN= suprachiasmatic nucleus or nuclei (SCN) is a tiny region of the brain in the hypothalamus, situated directly above the optic chiasm. It is responsible for controlling circadian rhythms. The neuronal and hormonal activities it generates regulate many different body functions in a 24-hour cycle, using around 20,000 neurons
Circadian rhythms help determine our sleep patterns. The body's master clock, or SCN, controls the production of melatonin, a hormone that makes you sleepy. It receives information about incoming light from the optic nerves, which relay information from the eyes to the brain.
Tips for healthy sleep
Here are some tips: Go to sleep and wake up at the same time each day. Avoid napping. Use the bed only for sleeping and being intimate. Try to avoid stress, fatigue, and sleep deprivation. Avoid vigorous exercise at least four hours prior to bedtime (but do exercise earlier in the day)
melatonin
Of the endocrine organs, the function of the pineal gland was the last discovered. Located deep in the center of the brain, the pineal gland was once known as the "third eye." The pineal gland produces melatonin, which helps maintain circadian rhythm and regulate reproductive hormones.
pineal gland secretes
The pineal gland is a tiny endocrine gland found in the brain. It produces and secretes the hormone melatonin, which is a hormone that helps regulate biological rhythms such as sleep and wake cycles. The secretion of melatonin is inhibited by light and triggered by darkness.
Hypnopompic hallucinations
hallucinations that occur when awakening from sleep; seen in narcolepsy
Hypnagogia, also referred to as "hypnagogic hallucinations"
is the experience of the transitional state from wakefulness to sleep: the hypnagogic state of consciousness, during the onset of sleep (for the transitional state from sleep to wakefulness see hypnopompic). Mental phenomena that may occur during this "threshold consciousness" phase include lucid thought, lucid dreaming, hallucinations, and sleep paralysis. However, sleep paralysis and lucid dreaming are separate sleep conditions that are sometimes experienced during the hypnagogic state.Threshold consciousness (commonly called "half-asleep" or "half-awake", or "mind awake body asleep") describes the same mental state of someone who is moving towards sleep or wakefulness, but has not yet completed the transition.
Infradian rhythms refer to those rhythms with a period
more than 24 hours... There are many examples of circadian rhythms, such as the sleep-wake cycle, the body-temperature cycle, and the cycles in which a number of hormones are secreted. Infradian rhythms have a period of more than 24 hours. The menstrual cycle in women and the hibernation cycle in bears are two good examples.