Which of the following is NOT one of the five main glands of the human body?

The pineal gland is indeed one of the five main glands in the endocrine system of the human body. It plays a role in regulating sleep patterns through the secretion of melatonin. The other glands mentioned, such as the thyroid, adrenal glands, and pituitary gland, are also essential components of the endocrine system, each with its vital functions.

The thyroid gland regulates metabolism and energy levels, the adrenal glands are involved in stress response and hormone production, and the pituitary gland, often called the "master gland," controls many other glands in the endocrine system and regulates various bodily functions, including growth and metabolism. Thus, all the options presented, except the pineal gland, are recognized as key glands. The distinction lies in the context of how one's understanding of "main" glands can vary, but generally, the specific five are commonly highlighted in many anatomical and physiological discussions.