Endocrine glands secrete ___________ into the bloodstream, where they travel to specific sites called ___________.
Endocrine System Endocrine glands-secrete chemical substances called hormones directly into the bloodstream for transport to target tissues.Hormones: three basic types 1. steroid hormones: are lipid originally synthesized from cholesterol There are more than 20 steroid hormones in the body, ie.ndocrine System Endocrine glands-secrete chemical substances called hormones directly into the bloodstream for transport to target tissues.