1. Endocrine system consists of ductless glands.
2. The glands secrete hormone directly into the bloodstream.
3. Pituitary gland is the 'boss' (master gland) because it controls the activity of other endocrine glands.
4. Even they function differently, endocrine system is complementary to nervous system and they work together for coordination and responses in human body.
ALL THE BEST!