Which term describes secretion to outside of the body via ducts?

Which term describes secretion to outside of the body via ducts?

• A. Endocrine
• B. Autocrine
• C. Paracrine
• D. Exocrine

Answer: (D)

Exocrine secretion is the process by which a gland releases its product onto an epithelial surface or into a duct that leads outside the body or into a hollow organ. This is what sweat glands do by sending sweat to the skin, and salivary glands by delivering saliva into the mouth. The pancreas also has an exocrine function, secreting digestive enzymes into the small intestine through a duct. In contrast, endocrine glands release hormones directly into the bloodstream, with no ducts involved, so their products travel to distant targets. Autocrine and paracrine signaling involve local action—substances released to affect the secreting cell itself or nearby cells—not through a duct to the exterior.

Exocrine secretion is the process by which a gland releases its product onto an epithelial surface or into a duct that leads outside the body or into a hollow organ. This is what sweat glands do by sending sweat to the skin, and salivary glands by delivering saliva into the mouth. The pancreas also has an exocrine function, secreting digestive enzymes into the small intestine through a duct.

In contrast, endocrine glands release hormones directly into the bloodstream, with no ducts involved, so their products travel to distant targets. Autocrine and paracrine signaling involve local action—substances released to affect the secreting cell itself or nearby cells—not through a duct to the exterior.