Which of the following lists endocrine glands?

• A. Lungs, kidneys, liver
• B. Pituitary gland, thyroid gland, parathyroid gland, adrenal glands, pancreas, gonads
• C. Lymph nodes, thymus, spleen
• D. Skin and hair

Answer: (B)

Endocrine glands release hormones directly into the bloodstream to regulate many bodily functions. The glands listed—pituitary, thyroid, parathyroid, adrenal glands, pancreas, and gonads—are all classic endocrine organs whose primary job is hormone secretion that influences growth, metabolism, calcium balance, stress response, blood sugar, and reproductive activity. The other groups include organs that mainly serve other systems: lungs, kidneys, and liver participate in respiration and filtration/metabolism; lymph nodes, thymus, and spleen belong to the immune/lymphatic system; and skin and hair are part of the integumentary system. Because the question is asking for the items that are endocrine glands, this set is the correct one.