Final answer:
The correct answer is A. anterior pituitary to release thyroid-stimulating hormone (TSH), which then stimulates the thyroid gland to release thyroid hormones T3 and T4 as part of a negative feedback system.
Step-by-step explanation:
In response to decreases in body temperature, the brain signals the: A. anterior pituitary to release thyroid-stimulating hormone (TSH). The anterior pituitary stimulates the thyroid gland to release thyroid hormones T3 and T4. As levels of these hormones rise, they provide negative feedback to the hypothalamus and anterior pituitary to inhibit further release of these hormones.
The hypothalamus secretes thyrotropin-releasing hormone (TRH), which travels to the anterior pituitary, and then TRH stimulates the anterior pituitary to secrete TSH. TSH encourages the thyroid gland to produce hormones, which then regulates the body's temperature back to normal. Should the levels get too high, TRH and TSH secretion is inhibited, thereby stopping the thyroid from overproducing its hormones. This system is an example of a negative feedback loop that maintains hormone levels within a narrow, healthy range.