BIOL 1080 Lecture Notes - Gastrointestinal Tract, Postprandial
25 Jan 2012
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Document Summary
When actually measured you see this pattern. This is almost the same amount that is lost during 50 years of aging! Chronobiology- the study of timescales and cycles in biology. Biological rhythms- cycles in all zones biological rhythmicity: ultradian (less than 24 hours)) and infradian (more than 24 hours) Circadian rhythm- biological rhythm based on a 24 hour cycle. Circadian rhythms are present in essential all physiological processes. They are controlled by gene expression, regulation of enzyme activities, neural function, hormone secretion. Circadian rhythms coordinates sleep, nutrient supply and activity patterns with the metabolic patterns required at different stages of the day. Disruption of circadian rhythms in experimental animals causes a wide spectrum of health problems and premature aging. The central clock is a brain region called the suprachiasmatic nucleus which keeps time based on light signals from the retina. Nearly every cell in the body has a subsidiary clock, which coordinates its metablosim with the rest of the body.
