Daily changes in light intensity major environmental

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: ynchronized with acAvity levels driven by surrounding environment 9 Circadian Rhythms •  The internal clock that regulates circadian rhythms is synchronized, or entrained to the daily Light ­Dark (LD) cycle and other social and environmental cues. •  Endogenous Period of the biological clock is ~ 24.2 hours •  The Aming of sleep usually bears a characterisAc relaAonship to the environment and to other circadian rhythms in the body. •  Daily changes in light intensity –  Major environmental cue used to adjust SCN master clock –  Photoreceptors in reAna pick up light signals and transmit them directly to SCN –  SCN relays message regarding light status to pineal gland 10 Visual System SCN 24-h LD Cycle Eye Retina Optic Chiasm Lateral Geniculate Visual Cortex 11 Human SCN 12 Melanopsin PhotosensiAve Ganglion Cell: A New ReAnal Photoreceptor 13 Sleep without a Biological Clock 14 Clinical Laboratory Values 15 SAmulus ­Response (SR): Time of Day Responses A. 100 75 50 25 Chemotherapeutic Agent 2 6 10 14 18 22 B. 100 75 50 25 Radiation C. 100 75 50 25 0 2 6 10 14 18 22 Bacterial Infection 2 6 10 14 18 22 Time of Day (hr) 16 Jet Lag 17 SR: Light and the RegulaAon of...
View Full Document

This note was uploaded on 11/15/2010 for the course BIO NPB 101 taught by Professor Dr.weidner during the Fall '10 term at UC Davis.

Ask a homework question - tutors are online