PSB-2000 Lecture Notes - Lecture 18: Circadian Rhythm, Jet Lag, Molecular Clock
Document Summary
Circadian rhythms: rhythms that last about a day; humans last around 24. 2: waking and sleeping, hormone secreion, urine producion, eaing and drinking, sensiivity to drugs. Age is an important factor: early in life you go to bed early and wake up early, people around 20 go to bed late and wake up late. To prepare for changes in environment before they occur: sunrise/sunset, temperature changes. They bird lies south when the paterning of light changes. A simulus that resets the biological clock: circadian rhythms persist without light (free-running) but light can reset them. Problem is that our endogenous rhythm doesn"t match external ime: easier to travel west than east, go west > phase delay, go east > phase advance. Duraion of sleep depends on when you go to bed. For those who work nigt shit tr to sleep during day but it is diicult: other circadian rhythms (like temp) do not adjust to new atempted sleep wake cycle.
