Which statement best distinguishes endocrine glands from exocrine glands in glandular epithelial tissue?

• A. Endocrine glands are always unicellular, whereas exocrine glands are always multicellular.
• B. Endocrine glands secrete hormones into the bloodstream or interstitial fluid and typically lack ducts, whereas exocrine glands secrete onto epithelial surfaces through ducts.
• C. Endocrine glands mainly produce enzymes for digestion, whereas exocrine glands mainly produce hormones that regulate distant target organs.
• D. Endocrine glands secrete their products into ducts that carry them to body surfaces, whereas exocrine glands release their products directly into capillaries.

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the definitions of endocrine and exocrine glands. Endocrine glands secrete their products (hormones) directly into the bloodstream or interstitial fluid, allowing these substances to travel to distant target organs.
2. Step 2: Recognize that endocrine glands typically lack ducts, meaning they do not have a physical passageway to carry their secretions to a surface or cavity.
3. Step 3: Understand that exocrine glands secrete their products onto epithelial surfaces, such as skin or the lining of the digestive tract, through ducts that serve as channels.
4. Step 4: Note that exocrine gland secretions often include enzymes, mucus, or other substances that act locally rather than systemically.
5. Step 5: Compare the options given and identify the statement that correctly highlights these key differences: endocrine glands secrete hormones into the bloodstream or interstitial fluid without ducts, while exocrine glands secrete onto epithelial surfaces through ducts.