Here's why:
* Endocrine glands are ductless glands, meaning they don't have a system of tubes or ducts to carry their secretions.
* Instead, they release hormones directly into the surrounding interstitial fluid, from where they diffuse into nearby capillaries and enter the bloodstream.
* The bloodstream then carries the hormones to target cells throughout the body, where they exert their specific effects.
This is in contrast to exocrine glands which secrete their products into ducts that lead to a specific location, such as sweat glands releasing sweat onto the skin.
