clock


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clock

(klok) a device for measuring time.
biological clock  the physiologic mechanism which governs the rhythmic occurrence of certain biochemical, physiologic, and behavioral phenomena in living organisms.

clock

(klŏk)
n.
1. An instrument other than a watch for measuring or indicating time, especially a mechanical or electronic device having a numbered dial and moving hands or a digital display.
2. A biological clock.
v. clocked, clocking, clocks
v.tr.
To register or record with a mechanical device: clocked the winds at 60 miles per hour.

clock′er n.

CLOCK

A gene on chromosome 4q12 that encodes a ubiquitously expressed human homolog of the mouse clock gene, which forms a heterodimer with ARNTL and activates E-box element transcription of several circadian clock proteins (e.g., PER1 and PER2). CLOCK is highly expressed in the suprachiasmatic nucleus.

Molecular pathology
CLOCK-ARNTL double mutations in the PAS domains result in syngernistic desensitisation to high levels of CRY on repression of CLOCK-ARNTL transcriptional activity of PER1, disrupting circadian rhythmicity.

clock

(klok)
A device for measuring time.

biological clock

1. An internal system in organisms that influences behavior in a rhythmic manner. Functions such as growth, feeding, secretion of hormones, the rate of drug action, the wake-sleep cycle, the menstrual cycle, and reproduction coincide with certain external events such as day and night, the tides, and the seasons. Biological clocks appear to be set by environmental conditions in some animals, but if these animals are isolated from their environment they continue to function according to the usual rhythm. A gradual change in environment does produce a gradual change in the timing of the biological clock. See: circadian; maladaptation to night work; zeitgeber
2. A colloquial term for the decrease in fertility that accompanies aging, particularly as women approach the age of 35.

Patient discussion about clock

Q. How do you wake up in the morning if your narcolepsy is so severe you can't hear the alarm clock, phone ring? biggest problem is sleep paralysis, can't wake up. Late for work, everything, life is suffering because of severity. Have tried ritalin, natural supplements, hypnosis therapy, Provigal, antidepressants, nothing seems to work. Employer thinks it's an excuse, friends are irritated, I'm at my wits end. Life is spent sleeping more than awake.

A. Narcolepsy cannot yet be cured. But EDS and cataplexy, the most disabling symptoms of the disorder, can be controlled in most patients with drug treatment. Often the treatment regimen is modified as symptoms change. For decades, doctors have used central nervous system stimulants-amphetamines such as methylphenidate, dextroamphetamine, methamphetamine, and pemoline-to alleviate EDS and reduce the incidence of sleep attacks. For most patients these medications are generally quite effective at reducing daytime drowsiness and improving levels of alertness. However, they are associated with a wide array of undesirable side effects so their use must be carefully monitored. Common side effects include irritability and nervousness, shakiness, disturbances in heart rhythm, stomach upset, nighttime sleep disruption, and anorexia. For full article: http://www.ninds.nih.gov/disorders/narcolepsy/detail_narcolepsy.htm#120393201 Hope this helps.

More discussions about clock
References in periodicals archive ?
IT'S time to spring forward this week so don't forget to set your clocks an hour later this weekend.
Just getting to the clock in the Petersham church, a winder needs to be in good shape.
Contemporary A Simple Chrome Clock with silver strokes to denote the hours suits modern interiors.
to) from users who want to know real time, mainly to set computer clocks.
The clock will stop for the change of possession, so going out of bounds will not be a blunder.
The Seth Thomas and Infinity Instruments clocks were the more moderately priced units, retailing from $29.
A clock by one of the great makers such as Charles Frodsham or Thomas Tompion will be substantially more desirable than a provincially made clock.
All trace lengths are typically required to be within half an inch from that of the strobe line to minimize clock skew.
In Richmond, Virginia's Chimborazo Hospital, male administrators used the clock to regiment sleep patterns and meal times.
Its movement spins gears that rotate the display-altering wheels of the clock face.
Sobel's tale concerns John Harrison, an obscure English watchmaker from a merchant-class background who believed clocks held the answer.
Recently, Durst had to take the clock down and revamp it to monitor the accelerated rate of federal debt increase, now more than $13,000 per second.