NEUR 2200 Lecture Notes - Lecture 21: Muscle Tone, Pineal Gland, Melatonin

• School: Carleton University
• Department: Neuroscience
• Course: NEUR 2200
• Professor: Matthew Holahan

Document Summary

Linked to the cycle of days and seasons. Animals living near the poles of the earth are more affected by seasonal changes than animals living in equatorial regions. Human behavior is governed more by daily cycles than by seasonal cycles. Biological clock: rhythms are endogenous (control from within) Allows animals to anticipate events before they happen (birds migrate before it gets cold) Infradian rhythm: less than a year (human menstrual cycle) Ultradian rhythm: less than a day (eating cycle) Free-running rhythm: rh(cid:455)th(cid:373) of the (cid:271)od(cid:455)"s o(cid:449)(cid:374) de(cid:448)isi(cid:374)g i(cid:374) the absence of all external cues (would be about 25 to 27 hours without external cues) Zeitgeber: e(cid:374)(cid:448)iro(cid:374)(cid:373)e(cid:374)tal e(cid:448)e(cid:374)t that e(cid:374)trai(cid:374)s (cid:271)iologi(cid:272)al rh(cid:455)th(cid:373)s; a (cid:862)ti(cid:373)e gi(cid:448)er(cid:863) (light resets the biological clock) Entrainment: determination or modification of the period of a biological rhythm through the superchiasmatic nucleus. Jet lag: disruption in the entrainment (plasticity) of a perso(cid:374)"s (cid:271)iologi(cid:272)al (cid:272)lo(cid:272)k. Suprachiasmatic nucleus: involved with circadian rhythms located just above the optic chiasm.