The endocrine system is a system of ductless glands that secrete their products into the interstitial fluid.

Endocrine System

A collection of glands in the body that secrete hormones directly into the circulatory system to be carried towards distant target organs.

Ductless Glands

Glands that release their secretions, such as hormones, directly into the bloodstream rather than through ducts, also known as endocrine glands.

Interstitial Fluid

The fluid that surrounds the cells of tissues, providing a medium through which nutrients and wastes can exchange between blood and cells.