PSYB64H3 Chapter 11: Chapter 11
Document Summary
Circadian rhythms - a repeating cycle of about 24 hours. To establish and maintain these rhythms, internal biological clocks interact with stimuli known as zeitgebers light is the most important zeitgeber (external cue for setting biological rhytms) for human beings. In the absence of light, human free running circadian rhythm (non synched with environmental cues) lasts 24. 2 24. 9 hours. Exposure to light resets or entrain the internal biological clock to the 24 hour cycle of the earth s rotation. Blind people and submarine people experience free running cycles that are longer than 24 hours, and these result in severe sleep disruptions. In addition to light, other zeitgebers include physical activity, feeding, body temperature, and sleep related hormones. Individual sleep patterns result from different versions of genes responsible for our internal clocks. Morning people = larks , night people = night owls many fall somewhere between the two.
