- The gland commonly referred to as the "master gland" of the endocrine system is the pituitary gland.
- This is because the pituitary gland plays a central role in regulating the functions of many other endocrine glands.
- It produces and secretes a variety of hormones that control growth, metabolism, and reproductive processes.

- Unlike other glands, the pituitary gland is directly influenced by the hypothalamus, allowing it to integrate signals from the nervous system and coordinate hormonal responses accordingly.
- For instance, it releases hormones such as growth hormone (GH), thyroid-stimulating hormone (TSH), adrenocorticotropic hormone (ACTH), and luteinizing hormone (LH), which affect the thyroid gland, adrenal glands, and gonads among others.

- In contrast, the adrenal gland primarily secretes hormones like cortisol and adrenaline involved in stress responses; the thyroid gland regulates metabolism via thyroid hormones; and the hypothalamus serves as the control center that regulates the pituitary gland itself.

Therefore, the pituitary gland's ability to influence multiple endocrine glands qualifies it as the "master gland" of the endocrine system.

Reference: Ganong's Review of Medical Physiology, 26th Edition, Chapter 11 - The Endocrine System, Page 345-355