BIOL 1080 Lecture Notes - Lecture 5: Circadian Rhythm, Jet Lag, Biopsy
2 Mar 2016
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Document Summary
Using the example of height as a biomarker of spinal osteoporosis: height needs to be regularly in each individual in order to be useful. Biomarkers measurements may change from day to day and from hour to hour within a day. Looking to the image on the right: there is a. 2cm daily variation in height (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 of biological rhythmicity: ultradian (less than. 24hrs), circadian (24hrs), and infradian (more than 24hrs) Circadian rhythms are present in essentially all physiological processes. They are controlled by gene expression, regulation of enzyme activities, neural function, hormone secretion, etc. Circadian rhythms coordinate sleep, nutrient supply and activity patterns with the metabolic patterns required at different stages of the day.
