Physiological Basis of Sleep and Wakefulness
Neurophysiology of sleep and wakefulness
The neurophysiology of sleep and wakefulness is complex, but is the result of the superimposition of higher neurological…
Neuroanatomy of sleep and wakefulness
The activity of the cerebral cortex is critical in determining whether sleep or wakefulness occurs, but it does…
Output from SCN - Circadian rhythms
Fibres leave the SCN to reach the ventrolateral preoptic area (VLPO) of the anterior hypothalamus multisynaptically. They initially…
Pineal gland - Circadian rhythms
The pineal gland contains a circadian pacemaker in some vertebrates, such as perching birds (passerines).
In…
Sleep rhythms
The diurnal cycling of sleep–wake rhythms maintains sleep and wakefulness in line with environmental time, but by itself…
Melatonin - Circadian rhythms
Melatonin production The clock in the SCN, through its neurological connections, has a circadian influence not only on sleep, but…
Circadian rhythm periodicity The characteristics of this rhythm generator are largely genetically determined. At least 12 genes have been identified on…
Impulses reach the SCN from retinal receptors which lie particularly in the lower and nasal quadrant of the…
Whether an individual is awake or asleep depends on the balance of forces promoting and inhibiting each of…
REM sleep is almost never normally entered from wakefulness except in infants. It is preceded by NREM sleep,…
This includes a variety of mechanisms that influence sleep but which are independent of the time spent awake…
Genito-urinary function Even before the onset of NREM sleep the heart rate falls in parallel with the reduction in body…
The minute ventilation falls (1.23) and the arterial Pco2 rises by 2–3mmHg. The stage of NREM sleep oscillates…
Less saliva is produced during sleep than during wakefulness, possibly partly related to a reduction in oromotor activity,…
The minute ventilation is reduced compared to NREM sleep and wakefulness [9], and the arterial Pco2…
Homeostatic control of cardiovascular function in response to, for instance, changes in blood volume or temperature is poor…
Genito-urinary function
Melatonin (N-5-methoxy-N-acetyl-tryptamine) is synthesized from tryptophan after it has been converted to 5HT
Coordination of circadian rhythms
Circadian rhythms
Circadian rhythms have a periodicity of around a day, which is longer than…
SCN clock genetics - Circadian rhythms
Input to SCN - Circadian rhythms
Control of sleep and wakefulness
REM sleep ultradian rhythm
Adaptive drive
Rapid eye movement (REM) sleep - Genito-urinary function
Sleep-related erections (nocturnal penile tumescence) develop rapidly during REM sleep, and may persist…
Non-rapid eye movement (NREM) sleep - Cardiovascular function
Non-rapid eye movement (NREM) sleep - Respiratory function
Non-rapid eye movement (NREM) sleep - Gastrointestinal function
Rapid eye movement (REM) sleep - Respiratory function
Rapid eye movement (REM) sleep - Cardiovascular function
Non-rapid eye movement (NREM) sleep - Genito-urinary function
There is considerable diurnal variation in renal function. Water and sodium are retained…
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