Which glands are part of the endocrine system?

• A. Thyroid, Liver, Kidney, Heart
• B. Hypothalamus, Pituitary, Thyroid, Pancreas
• C. Thyroid, Pancreas, Adrenal, Spleen
• D. Adrenal, Liver, Gallbladder, Brain

Answer: (B)

The endocrine system is composed of glands that secrete hormones directly into the bloodstream to regulate various bodily functions, including metabolism, growth, and mood. In the context of the options provided, the hypothalamus, pituitary, thyroid, and pancreas are all recognized components of the endocrine system.

The hypothalamus plays a crucial role in linking the nervous system to the endocrine system and regulates the release of hormones from the pituitary gland. The pituitary gland, often referred to as the "master gland," controls other endocrine glands and releases hormones that influence various physiological processes. The thyroid gland produces hormones that regulate metabolism and energy levels. The pancreas has both exocrine and endocrine functions, primarily involved in regulating blood sugar levels through the production of insulin and glucagon.

Contrastingly, other options include glands like the liver and spleen, which are not classified as endocrine glands despite having vital functions in the body. The liver does play a role in hormone metabolism and has some endocrine functions but is not primarily recognized as an endocrine gland. The gallbladder is an organ involved in digestion but does not secrete hormones, and the adrenal glands, while important, are not included in the incorrect options presented.