Exocrine glands differ from endocrine glands in that exocrine glands:

• A. Secrete their products into ducts that deliver them to an epithelial surface or lumen
• B. Produce only lipid-based hormones and have no role in producing enzymes or mucus
• C. Release their products directly into the bloodstream or interstitial fluid
• D. Lack secretory cells and instead rely on filtration across capillary walls

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the basic difference between exocrine and endocrine glands. Exocrine glands secrete their products through ducts, while endocrine glands release hormones directly into the bloodstream.
2. Step 2: Recall that exocrine glands produce substances such as enzymes, mucus, and other secretions that need to be delivered to specific surfaces or cavities, not directly into the blood.
3. Step 3: Recognize that endocrine glands produce hormones, which are chemical messengers released into the interstitial fluid and then absorbed into the bloodstream to reach target organs.
4. Step 4: Evaluate each option by matching it with the known characteristics of exocrine glands: they secrete through ducts, produce enzymes or mucus, and do not release products directly into the blood.
5. Step 5: Conclude that the correct distinguishing feature of exocrine glands is that they secrete their products into ducts that deliver them to an epithelial surface or lumen.