The network of glands that release chemical messengers directly into the bloodstream is called the

The network of glands that release chemical messengers directly into the bloodstream is called the endocrine system.  The endocrine system produces and secretes these chemical messengers, referred as hormones directly into bloodstream  to transmit signals to appropriate part of body. The hormones regulate bodily functions like growth, metabolism, tissue function, sexual function, reproduction, sleep and mood. 

Iwould say silver and gold