Health

Does penile tumescence have any relation to sleep architecture? Since the 1970s, it has been known that nocturnal erections are phenomena of REM sleep. Therefore, the classic hypogonadal teaching that decreased morning erections are caused by low testosterone levels may be related to more than one primary problem. The patient with decreased or absent morning …

Does penile tumescence have any relation to sleep architecture Read More »

What are the sleep characteristics associated with rising AM testosterone levels? There is accumulating evidence in adult men that the testosterone profile is significantly influenced by NREM–REM cycling. Sleep architecture, characteristics which is associated with a nocturnal rise in am testosterone, as follows: (1) duration of the first NREM period; (2) daytime recovery sleep; (3) …

Sleep characteristics associated with rising AM testosterone levels Read More »

How does gonadotropin release change from youth to adulthood, and is the LH adulthood pattern solely responsible for gonadal steroid release? a. Regarding changes to maturity: Sexual maturity is geared to enable men and women to achieve daily sperm and monthly egg production, respectively. There is a pulsatile release of both luteinizing hormone (LH) and follicle-stimulating hormone …

How does gonadotropin release change from youth to adulthood Read More »

Hormones elevated early in sleep and elevated late in sleep Recall that SWS predominates during the first third of sleep and REM predominates during the last half of sleep. GH and prolactin (PRL) are entrained to SWS. The increase in GH secretion during sleep is well known. Regardless of age and gender, most PRL secretion …

Hormones elevated early in sleep and elevated late in sleep Read More »

How is melatonin involved in regulation of circadian rhythms, and are there any other hormones that contribute to circadian rhythm regulation? Melatonin communicates a chemical message of LD cycling peripherally, that is, to the remainder of the body. Melatonin levels are involved in synchronization of circadian rhythms through a circuitous neural communication to the SCN …

Circadian rhythm regulation Read More »

On the basis of the description of the circadian system, what is “entrainment,” and how is it related to “synchronization” of circadian rhythms Circadian rhythms are synchronized to the 24-hour day through the process of entrainment. As outlined above, the SCN is the master autonomous pacemaker for biologic rhythms, but is set at > 24 …

Entrainment of circadian rhythms Read More »

Since the circadian oscillatory network has three components (SCN, entrainment, and tissue oscillators), what is the basic SCN organization and the basic molecular mechanisms of the circadian clock systems? The SCN cytoarchitecture reveals functional organization. In mammals, the SCN comprises some 100,000 neurons and is divided into a primarily light-sensitive SCN core , which receives the unique …

SCN organization of the circadian clock systems Read More »