Suprachiasmatic Nucleus (SCN)

A pair of small nuclei in the hypothalamus that serves as the body's primary circadian pacemaker, regulating sleep-wake cycles and other daily rhythms.

Key Functions:

• Acts as the master circadian pacemaker.
• Receives light input from the retinohypothalamic tract.
• Regulates the secretion of melatonin from the pineal gland.
• Synchronizes internal biological rhythms with the external light-dark cycle.

Interacting Systems & Components:

• Hypothalamus (located within)
• Retinohypothalamic Tract (receives input from)
• Pineal Gland (regulates melatonin secretion)
• Circadian Rhythm (primary regulator of)