Pineal Gland Ripple Ireland

Where is it located?  Between two hemispheres of brain  Tucked into groove where two rounded thalamic bodies join  Dorsal aspects of brain’s diencephalon region  Part of both nervous system and endocrine system

What hormones does it produce?  Melatonin  derived from tryptophan, regulates circadian rhythm (sleep cycle) and body temperature

What effect does the hormone have?  Regulation of sleep patterns and seasonal functions (i.e. hibernation)  Influences sexual development, hibernation, and seasonal breeding  Helps protect body from cell damage caused by free radicals  Jet lag

Why is this hormone important to homeostasis?  Homeostatic sleep schedule  thermoregulation

Feedback Mechanisms and Antagonistic Hormones  Source of circadian rhythms (sleep patterns) lies in suprachiasmatic nuclei (SCNs)  Day: SCN decreases melatonin production  Night: SCN increases melatonin production

What releases/inhibits melatonin production?  Inhibited when retina detects light  Stimulated when in darkness

What happens if the gland does not function properly?  Too much  Drowsiness/insomnia  Reduced core body temperature  Not enough/not at all  Seasonal Affective Disorder (SAD) – depression in winter  More inflammation  Weakened immune system  Increased risk of cancer

What can be done?  Supplements are available  Doses of melatonin can be used to treat depression, insomnia, and jet lag.

Sources  