-The endocrine system is the information signaling system.
-Their glands produce hormones.
-This system regulates mood, growth and development, tissue function and metabolism.

-The hypothalamus controls body temperature, hunger, thirst, fatigue, anger, and circadian cycles.
-It secretes hormones to tell other glands to create their hormone GHRH


-The pineal body secretes melatonin
-Melatonin may help regulate sleep patterns.