Final answer:
The organ system that includes the pituitary gland, adrenal gland, and thyroid gland is the endocrine system, which plays a key role in homeostasis and hormone secretion.
Step-by-step explanation:
Which organ system includes the pituitary gland, adrenal gland, and thyroid gland?
The organ system that includes the pituitary gland, adrenal gland, and thyroid gland is the endocrine system. This system is integral for maintaining homeostasis through the secretion of hormones. The endocrine glands secrete hormones into the interstitial fluid, which then enter the bloodstream to reach organs and tissues. Importantly, the pituitary gland, often referred to as the master gland, controls other endocrine glands and has a close relationship with the hypothalamus, which is a part of the brain overseeing the endocrine system.
The thyroid gland, adrenal glands, and pituitary are prominent members of the endocrine system. The thyroid gland regulates metabolism and calcium balance, the adrenal glands respond to stress and metabolism, and the pituitary gland regulates various physiological processes by releasing hormones that influence other glands.
Therefore, the correct answer to the question is Option A. endocrine.