How do exocrine glands differ from endocrine glands in terms of secretion site?

• A. Exocrine secretes onto surfaces or into ducts; endocrine releases hormones into the bloodstream.
• B. Exocrine releases hormones into the bloodstream; endocrine secretes onto surfaces or into ducts.
• C. Both secrete into ducts
• D. Endocrine secretes onto surfaces

Answer: (A)

Exocrine glands secrete their products onto surfaces or into ducts that carry the secretions to a body surface or organ lumen. Think of saliva into the mouth or sweat onto the skin—that’s secretion through a duct system to a site outside the tissue where the gland resides. Endocrine glands, on the other hand, release hormones directly into the bloodstream, so the signals travel through blood to distant target organs and tissues.

So the key idea is: exocrine glands use ducts or surface sites for secretion, while endocrine glands release hormones into the circulatory system.